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Honda Fit/Jazz - Fuel and Emissions System Description - Except L12A4, L13A6, L15A1(IN model) and L15A6 (Without VSA)

Fuel and Emissions System Description - Except L12A4, L13A6, L15A1(IN model) and L15A6

Electronic Control System


The functions of the fuel and emission control systems are managed by the engine control module (ECM) on vehicles with manual transmissions or the powertrain control module (PCM) on vehicles with automatic transmissions.

Fail-safe Function

When an abnormality occurs in a signal from a sensor, the ECM/PCM ignores that signal and assumes a pre-programmed value for that sensor that allows the engine to continue to run.

Back-up Function

When an abnormality occurs in the ECM/PCM, the injectors are controlled by a back-up circuit independent of the system to permit minimal driving.

Self-diagnosis

When an abnormality occurs in the signal from a sensor, the ECM/PCM supplies ground for the malfunction indicator lamp (MIL) and stores the diagnostic trouble code (DTC) in erasable memory. When the ignition is first turned on, the ECM/PCM supplies ground for the MIL for 2 seconds to check the MIL bulb condition.

Two Driving Cycle Detection Method

To prevent false indications, the ‘‘two driving cycle detection method'' is used for some self-diagnostic functions. When an abnormality occurs, the ECM/PCM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and ON (II) again, the ECM/PCM informs the driver by turning on the MIL.

ECM/PCM Data


You can retrieve data from the ECM/PCM by connecting the HDS or the scan tool to the Data Link Connector (DLC). The items listed in the table below conform to SAE recommended practice. The HDS also reads data beyond that recommended by SAE so that this data may help you find the causes of intermittent problems.

NOTE:

DataDescriptionOperating ValueFreeze Data
Diagnostic Trouble Code (DTC)If the ECM/PCM detects a problem, it will store it as a code consisting of one letter and four numbers. Depending on the problem, an SAE-defined code (P0xxx) or a Honda-defined code (P1xxx) will be output to the tester.If no problem is detected, there is no output.YES
Engine SpeedThe ECM/PCM computes engine speed from the signals sent from the Crankshaft Position (CKP) sensor. This data is used for determining the time and amount of injected fuel.Nearly the same as tachometer indication
At idle speed:
L13A1 engine (M/T) for KQ, KK, KT, KB models
700±50 rpm (min-1)
YES
Vehicle SpeedThe ECM/PCM converts pulse signals from the Vehicle Speed Sensor (VSS).Nearly the same as speedometer indicationYES
Manifold Absolute Pressure (MAP)The absolute pressure caused in the intake manifold by engine load and speed.With engine stopped: Nearly the same as atmospheric pressure
At idle speed: about 20-34 kPa (150-260 mmHg, 6-10 in.Hg), 0.7-1.1 V
YES
Engine Coolant Temperature (ECT)The ECT sensor converts coolant temperature into voltage and signals the ECM/PCM. The sensor is a thermistor whose internal resistance changes with coolant temperature. The ECM/PCM uses the voltage signals from the ECT sensor to determine the amount of injected fuel.With cold engine: Same as ambient temperature and IAT
With engine warmed up: about 80-100°C (176-212°F), 0.5-0.8 V
YES
Primary Heated Oxygen Sensor (Primary HO2S), (Sensor 1) Secondary Heated Oxygen Sensor (Secondary HO2S) (Sensor 2)The HO2S detects the oxygen content in the exhaust gas and sends voltage signals to the ECM/PCM. Based on these signals, the ECM/PCM controls the air fuel ratio. When the oxygen content is high (that is, when the ratio is leaner than the stoichiometric ratio), the voltage signal is lower. When the oxygen content is low (that is, when the radio is richer than the stoichiometric ratio), the voltage signal is higher.0.0-1.25 V
At idle speed:
about 0.1-0.9 V
NO

ECM/PCM Data (cont'd)


DataDescriptionOperating ValueFreeze Data
Fuel System StatusFuel system status is indicated as ''open'' or ''closed''.
Closed: Based on the A/F sensor and HO2S output, the ECM/PCM determines the air/fuel ratio and controls the amount of injected fuel.
Open: ignoring the A/F sensor and HO2S output, the ECM/PCM refers to signals from the throttle position (TP), manifold absolute pressure (MAP), intake air temperature (IAT), barometric pressure (BARO) and engine coolant temperature (ECT) sensors to control the amount of injected fuel.
At idle speed: closedYES
Short Term Fuel TrimThe air/fuel ratio correction coefficient for correcting the amount of injected fuel when the Fuel System Status is ‘‘closed''. When the ratio is leaner than the stoichiometric ratio, the ECM/PCM increases short term fuel trim gradually, and the amount of injected fuel increases. The air/fuel ratio gradually gets richer, causing a lower oxygen content in the exhaust gas. Consequently, the short term fuel trim is lowered, and the ECM/PCM reduces the amount of injected fuel.
This cycle keeps the air/fuel ratio close to the stoichiometric ratio when in closed loop status.
0.70-1.47YES
Long Term Fuel TrimLong term fuel trim is computed from short term fuel trim and indicates changes occurring in the fuel supply system over a long period.
If long term fuel trim is higher than 1.00, the amount of injected fuel must be increased. If it is lower than 1.00, the amount of injected fuel must be reduced.
0.72-1.35YES
Intake Air Temperature (IAT)The IAT sensor converts intake air temperature into voltage and signals the ECM/PCM. When intake air temperature is low, the internal resistance of the sensor increases, and the voltage signal is higher.With cold engine:
Same as ambient temperature and ECT
YES
Throttle PositionBased on the accelerator pedal position, the opening angle of the throttle valve is indicated.At idle speed:
about 10 %, 0.5 V
YES
Ignition TimingIgnition timing is the ignition advance angle set by the ECM/PCM. The ECM/PCM matches ignition timing to the driving conditions.At idle speed: 8°±5°BTDC when the SCS service signal line is jumped with the HDSNO
Caluculated Load Valve (CLV)CLV is the engine load calculated from the MAP data.At idle speed:
12-34 %
At 2,500 rpm (min-1) with no load:
15-25 %
YES

Except L15A1, L15A5 engines


ECM/PCM Inputs and Outputs at Connector A (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1*4BLK/WHTPHO2SHTC (PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S) HEATER CONTROL)Drives primary HO2S heaterWith ignition switch ON (II): battery voltage
With fully warmed up engine running: duty controlled
2YEL/BLKIGP2 (POWER SOURCE)Power source for the ECM/PCM circuitWith the ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
3YEL/BLKIGP1 (POWER SOURCE)Power source for the ECM/PCM circuitWith the ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
4BRNPG2 (POWER GROUND)Ground for the ECM/PCM circuitLess than 0.1 V at all times
5BLKPG1 (POWER GROUND)Ground for the ECM/PCM circuitLess than 0.1 V at all times
6*4WHTPHO2S (PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S) SENSOR 1)Detects primary HO2S sensor (sensor 1) signalWith throttle fully opened from idle with fully warmed up engine: about 0.6 V
With throttle quickly closed: below 0.4 V
7BLUCKP (CRANKSHAFT POSITION SENSOR)Detects CKP sensor signalWith engine running: pulses
9RED/BLUKS (KNOCK SENSOR)Detects knock sensor signalWith engine knocking: pulses
With ignition switch ON (II): about 0 V
10GRN/BLKSG2 (SENSOR GROUND)Sensor groundLess than 0.1 V at all times
11GRN/WHTSG1 (SENSOR GROUND)Sensor groundLess than 0.1 V at all times
12BLK/BLUIACV (IDLE AIR CONTROL (IAC) VALVE)Drives IAC valveWith engine running: duty controlled
13WHT/BLKEGRP (EXHAUST GAS RECIRCULATION (EGR) VALVE POSITION SENSOR)Detects EGR valve position sensor signalWith engine running: 1.2-2.0 V (depending on EGR valve lift)
15RED/BLKTPS (THROTTLE POSITION (TP) SENSOR)Detects TP sensor signalWith throttle fully open: about 4.8 V
With throttle fully closed: about 0.5 V

*4:Except IN model

ECM/PCM Inputs and Outputs at Connector A (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
16WHT/BLKIGPLS3E (No. 3 REAR IGNITION COIL PULSE)Drives No. 3 rear ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
18*2BLU/WHTVABS (VEHICLE SPEED SIGNAL FROM ABS)Input vehicle speed from ABS control unitDepending on vehicle speed: pulses
18*1BLU/WHTVSS (VEHICLE SPEED SENSOR (VSS))Detects VSS signalWith ignition switch ON (II) and front wheels rotating: cycles 0-about 5 V or battery voltage
19RED/GRNMAP (MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR)Detects MAP sensor signalWith ignition switch ON (II): about 3 V
At idle: about 1.0 V (depending on engine speed)
20YEL/BLUVCC2 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
21YEL/REDVCC1 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
23BRN/YELLG2 (LOGIC GROUND)Ground for the ECM/PCM circuitLess than 0.1 V at all times
24BRN/YELLG1 (LOGIC GROUND)Ground for the ECM/PCM circuitLess than 0.1 V at all times
26GRNCMP (CAMSHAFT POSITION (CMP) SENSOR (TDC (TOP DEAD CENTER (TDC) SENSOR))Detects CMP (TDC) sensorWith engine running: pulses
27WHT/BLUIGPLS4I (No. 4 FRONT IGNITION COIL PULSE)Drives No. 4 ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
28WHT/BLKIGPLS3I (No. 3 FRONT IGNITION COIL PULSE)Drives No. 3 front ignition coil
29WHT/GRNIGPLS2I (No. 2 FRONT IGNITION COIL PULSE)Drives No. 2 front ignition coil
30WHTIGPLS1I (No. 1 FRONT IGNITION COIL PULSE)Drives No. 1 front ignition coil
31*5GRN/REDIMA (IDLE MIXTURE ADJUSTER (IMA))Detects IMA signalWith ignition switch ON (II): about 0.5-4.5 V (depending on idle mixture)

*1:M/T
*2:CVT
*5:IN model

ECM/PCM Inputs and Outputs at Connector B (24P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1WHTIGPLS1E (No. 1 REAR IGNITION COIL PULSE)Drives No. 1 rear ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
2YELINJ4 (No. 4 INJECTOR)Drives No. 4 injectorWith ignition switch ON (II): battery voltage
At idle: duty controlled
3BLUINJ3 (No. 3 INJECTOR)Drives No. 3 injector
4REDINJ2 (No. 2 INJECTOR)Drives No. 2 injector
5BRNINJ1 (No. 1 INJECTOR)Drives No. 1 injector
6GRNFANC (RADIATOR FAN CONTROL)Drives radiator fan relayWith radiator fan running: about 0 V
With radiator fan stopped: battery voltage
7*2GRN/WHTHLCLS+ (CVT DRIVEN PULLEY CONTROL VALVE +SIDE)Drives CVT driven pulley control valveWith ignition switch ON (II): pulsing signal
8RED/WHTECT (ENGINE COOLANT TEMPERATURE SENSOR)Detects ECT sensor signalWith the ignition switch ON (II): about 0.1-4.8 V
(depending on engine coolant temperature)
10WHT/GRNIGPLS2E (No. 2 REAR IGNITION COIL PULSEDrives No. 2 rear ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
11*3RED/WHTMIND (M INDICATOR)Drives M indicator lightWith M indicator light turned ON: about 6 V
With M indicator light turned OFF: 0 V voltage
12*2LT GRNSIND (S INDICATOR)Drives S indicator lightWith S indicator light turned ON: about 6 V
With S indicator light turned OFF: 0 V voltage
13WHT/REDALTF (ALTERNATOR FR SIGNAL)Detects alternator FR signalWith engine running: about 0-5 V
(depending on electrical load)
14PNKEGR (EXHAUST GAS RECIRCULATION (EGR) VALVE)Drives EGR valveWith EGR operating: duty controlled
With EGR not operating: about 0 V
16*2YELSCLS+ (CVT START CLUTCH PRESSURE CONTROL VALVE +SIDE)Drives CVT start clutch pressure control valveWith ignition switch ON (II): pulsing signal
17RED/YELIAT (INTAKE AIR TEMPERATURE SENSOR)Detects IAT sensor signalWith ignition switch ON (II): about 0.1-4.8 V
(depending on intake air temperature)
18WHT/GRNALTC (ALTERNATOR CONTROL)Sends alternator control signalWith engine running: about 0-5 V
(depending on electrical load)
19*3LT GRN/REDS-DN (DOWN SHIFT SWITCH)Detects downshift switch signalSteering shift switch pushed toward downshift position (marked with -): 0 V
Steering shift switch in neutral position: about 5 V
20*3YELS-UP (UP SHIFT SWITCH)Detects upshift switch signalSteering shift switch pushed toward upshift position (marked with +): 0 V
Steering shift switch in neutral position: about 5 V
21RED/YELPCS (EVAPORATIVE EMISSION (EVAP) CANISTER PURGE VALVE)Drives EVAP canister purge valveWith engine running, engine coolant below 70°C (158°F): about 0 V
With engine running, engine coolant above 70°C (158°F): duty controlled
22WHT/BLUIGPLS4E (No. 4 REAR IGNITION COIL PULSEDrives No. 4 rear ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
24*2BLU/WHTSHLS+ (CVT DRIVE PULLEY CONTROL VALVE +SIDE)Drives CVT drive pulley control valveWith ignition switch ON (II): duty controlled

*2:CVT
*3:HONDA CVT+7SPEED MODE system

PCM Inputs and Outputs at Connector C (22P)*2

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1PNK/BLKHLCLS- (CVT DRIVEN PULLEY CONTROL VALVE -SIDE)Drives CVT driven pulley control valve
3BRNPG (CVT2) (POWER GROUND CVT2)Ground for the PCM circuit
5BLKPG (CVT1) (POWER GROUND CVT1)Ground for the PCM circuit
6GRN/BLKINHSOL (INHIBITOR SOLENOID CONTROL)Drives inhibitor solenoidWith inhibitor solenoid ON: battery voltage
With inhibitor solenoid OFF: 0 V
7RED/BLUNDR (CVT DRIVE PULLEY SPEED SENSOR)Detects CVT drive pulley speed sensor signalWith ignition switch ON (II): 0 V or 5 V
8PNK/BLUSCLS- (CVT START CLUTCH PRESSURE CONTROL VALVE B -SIDE)Drives CVT start clutch pressure control valve
9BLU/WHTATPS (TRANSMISSION RANGE SWITCH S POSITION)Drives transmission range switch S position signalIn S position: 0 V
In any other position: about 5 V or battery voltage
10WHTATPR (TRANSMISSION RANGE SWITCH R POSITION)Detects transmission range switch R position signalIn R position: 0 V
In any other position: about 10 V
11BLUATPL (TRANSMISSION RANGE SWITCH L POSITION)Detects transmission range switch L position signalIn L position: 0 V
In any other position: about 10 V
12LT GRNATPNP (TRANSMISSION RANGE SWITCH NEUTRAL/PARK POSITION)Detects transmission range switch Neutral/Park position signalIn Park or Neutral: 0 V
In any other position: about 10 V
13*3YELMSW (MAIN SWITCH)Detects main switch
(7SPEED MODE) signal
Main switch (7SPEED MODE) pushed: 0 V
Main switch (7SPEED MODE) released: about 5 V
15WHTNDN (CVT DRIVEN PULLEY SPEED SENSOR)Detects CVT driven pulley speed sensor signalWith ignition switch ON (II): 0 V or 5 V
16GRN/YELSHLS- (CVT DRIVE PULLEY CONTROL VALVE -SIDE)Drives CVT drive pulley control valveWith ignition switch ON (II): pulses
20PNKATPD (TRANSMISSION RANGE SWITCH D POSITION)Detects transmission range switch D position signalIn D position: about 0 V
In any other position: about 5 V
22WHT/REDVEL1 (CVT SPEED SENSOR)Detects CVT speed sensorDepending on vehicle speed: pulses
When vehicle is stopped: about 0 V or about 5 V

*2:CVT
*3:HONDA CVT+7SPEED MODE system

ECM/PCM Inputs and Outputs at Connector E (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1GRN/YELIMO FPR (IMMOBILIZER FUEL PUMP RELAY)Drives PGM-FI main relay 20 V for 2 seconds after turning ignition switch ON (II), then battery voltage
2*4WHT/REDSHO2S (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S), SENSOR 2)Detects secondary HO2S (sensor 2) signalWith throttle fully opened from idle with fully warmed up engine: above 0.6 V
With throttle quickly closed: below 0.4 V
3BRN/YELLG3 (LOGIC GROUND)Ground for the ECM/PCM control circuitLess than 0.1 V at all times
4PNKSG3 (SENSOR GROUND)Sensor groundLess than 0.1 V at all times
5GRN/WHTFUP (FUEL INJECTION SIGNAL)Sends fuel injection signal to gauge assemblyWith ignition switch ON (II): pulses
6*4BLK/WHTSHO2SHTC (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S) HEATER CONTROL)Drives secondary HO2S heaterWith ignition switch ON (II): battery voltage
With fully warmed up engine running: duty controlled
7RED/YELMRLY (PGM-FI MAIN RELAY)Drives PGM-FI main relay 1 Power source for the DTC memoryWith ignition switch ON (II): about 0 V
With ignition switch OFF: battery voltage
8*3BLU/WHTLED ADrives shift indicatorIn 7SPEED MODE:
  • in 1st, 2nd, 3rd and 7th: about 0.3 V
  • in 4th, 5th, and 6th: about 5 V
9YEL/BLKIG1 (IGNITION SIGNAL)Detects ignition signalWith ignition switch ON (II): battery voltage
With ignition switch OFF: about 0 V
11PNKDIND (D INDICATOR)Drives D indicator lightWith D indicator light turned ON: about 6 V
With D indicator light turned OFF: 0 V
12BLUTACDetects evaporator sensor signalWith ignition switch ON (II): about 0.1-4.8 V (depending on evaporator temperature)
13*2BLU/REDSLC (SHIFT LOCK CONTROL)Drives shift lock solenoidWith ignition switch ON (II), in Park position, brake pedal pressed, and accelerator pedal released: 0 V
14*6GRN/BLKACT TMP (A/C TEMPERATURE DIAL)Detects A/C Temperature dial signalWith ignition switch ON (II): about 0.5-4.5 V (depending on A/C temperature dial)
15GRN/REDELD (ELECTRICAL LOAD DETECTOR (ELD))Detects ELD signalWith ignition switch ON (II): about 0.1-4.8 V (depending on electrical load)

*2:CVT
*3:HONDA CVT+7SPEED MODE system
*4:Except IN model
*6:Without heater

ECM/PCM Inputs and Outputs at Connector E (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
18REDACC (A/C CLUTCH RELAY)Drives A/C clutch relayWith compressor ON: about 0 V
With compressor OFF: battery voltage
19*6RED/WHTVCC3 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
20*3GRN/BLKLED CDrives shift indicatorIn 7SPEED MODE:
  • in 2nd, 4th, 6th and 7th: about 0.3 V
  • in 1st, 3rd and 5th: about 5 V
21*3RED/WHTLED BDrives shift indicatorIn 7SPEED MODE:
  • in 1st, 4th, 5th and 7th: about 0.3 V
  • in 2nd, 3rd and 6th: about 5 V
22WHT/BLKBKSW (BRAKE PEDAL POSITION SWITCH)Detects brake pedal position switch signalWith brake pedal released: about 0 V
With brake pedal pressed: battery voltage
23RED/WHTK-LINESends and receives HDS or scan tool signalWith ignition switch ON (II): battery voltage
24GRNMTRTWSends engine coolant temperature signalWith ignition switch ON (II): pulse
25BLU/YELVSSOUT (VEHICLE SPEED SENSOR (VSS) OUTPUT SIGNAL)Sends vehicle speed sensor signalDepending on vehicle speed: pulses
26BLUNEP (ENGINE SPEED PULSE)Outputs engine speed pulseWith engine running: pulses
27RED/BLUIMOCD (IMMOBILIZER CODE)Detects immobilizer signal
28BLU/WHTACS (A/C SWITCH SIGNAL)Detects A/C switch signalWith A/C switch ON: 0 V
With A/C switch OFF: about 5 V
29BRNSCS (SERVICE CHECK SIGNAL)Detects service check signalWith the service check signal shorted with the HDS or the scan tool: about 0 V
With the service check signal opened: about 5 V
30RED/BLUWEN (WRITE ENABLE SIGNAL)Detects write enable signalWith ignition switch ON (II): about 0 V
31GRN/ORNMIL (MALFUNCTION INDICATOR LAMP)Drives MILWith MIL turned ON: about 0 V
With MIL turned OFF: battery voltage

*3:HONDA CVT+7SPEED MODE system
*6:Without heater

L15A1, L15A5 engines


ECM/PCM Inputs and Outputs at Connector A (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1*4BLK/WHTPHO2SHTC (PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S) HEATER CONTROL)Drives primary HO2S heaterWith ignition switch ON (II): battery voltage
With fully warmed up engine running: duty controlled
2YEL/BLKIGP2 (POWER SOURCE)Power source for the ECM/PCM circuitWith the ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
3YEL/BLKIGP1 (POWER SOURCE)Power source for the ECM/PCM circuitWith the ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
4BLKPG2 (POWER GROUND)Ground for the ECM/PCM circuitLess than 1.0 V at all times
5BLKPG1 (POWER GROUND)Ground for the ECM/PCM circuitLess than 1.0 V at all times
6*4WHTPHO2S (PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S) SENSOR 1)Detects primary HO2S sensor (sensor 1) signalWith throttle fully opened from idle with fully warmed up engine: about 0.6 V
With throttle quickly closed: below 0.4 V
7BLUCKP (CRANKSHAFT POSITION SENSOR)Detects CKP sensor signalWith engine running: pulses
9RED/BLUKS (KNOCK SENSOR)Detects knock sensor signalWith engine knocking: pulses
With ignition switch ON (II): about 0 V
10GRN/BLKSG2 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
11GRN/WHTSG1 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
12BLK/BLUIACV (IDLE AIR CONTROL (IAC) VALVE)Drives IAC valveWith engine running: duty controlled
13*6WHT/BLKEGRP (EXHAUST GAS RECIRCULATION (EGR) VALVE POSITION SENSOR)Detects EGR valve position sensor signalWith engine running: 1.2-2.0 V
(depending on EGR valve lift)
15RED/BLKTPS (THROTTLE POSITION (TP) SENSOR)Detects TP sensor signalWith throttle fully open: about 4.8 V
With throttle fully closed: about 0.5 V

*4:Except IN model
*6:Except IN, KH models

ECM/PCM Inputs and Outputs at Connector A (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
18*1BLU/WHTVSS (VEHICLE SPEED SENSOR (VSS))Detects VSS signalWith ignition switch ON (II) and front wheels rotating: cycles 0-about 5 V or battery voltage
18*2BLU/WHTVABS (VEHICLE SPEED SIGNAL FROM ABS)Input vehicle speed from ABS control unitDepending on vehicle speed: pulses
19RED/GRNMAP (MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR)Detects MAP sensor signalWith ignition switch ON (II): about 3 V
At idle: about 1.0 V (depending on engine speed)
20YEL/BLUVCC2 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
21YEL/REDVCC1 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
23BRN/YELLG2 (LOGIC GROUND)Ground for the ECM/PCM circuitLess than 1.0 V at all times
24BRN/YELLG1 (LOGIC GROUND)Ground for the ECM/PCM circuitLess than 1.0 V at all times
26GRNCMP (CAMSHAFT POSITION (CMP) SENSOR (TDC (TOP DEAD CENTER (TDC) SENSOR))Detects CMP (TDC) sensorWith engine running: pulses
27WHT/BLUIGPLS4 (No. 4 IGNITION COIL PULSE)Drives No. 4 ignition coilWith ignition switch ON (II): about 0 V
With engine running: pulses
28WHT/BLKIGPLS3 (No. 3 IGNITION COIL PULSE)Drives No. 3 ignition coil
29WHT/GRNIGPLS2 (No. 2 IGNITION COIL PULSE)Drives No. 2 ignition coil
30WHTIGPLS1 (No. 1 IGNITION COIL PULSE)Drives No. 1 ignition coil
31*5GRN/REDIMA (IDLE MIXTURE ADJUSTER (IMA))Detects IMA signalWith ignition switch ON (II): about 0.5-4.5 V
(depending on idle mixture)

*1:M/T
*2:CVT
*5:IN model

ECM/PCM Inputs and Outputs at Connector B (24P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
2YELINJ4 (No. 4 INJECTOR)Drives No. 4 injectorWith ignition switch ON (II): battery voltage
At idle: duty controlled
3BLUINJ3 (No. 3 INJECTOR)Drives No. 3 injector
4REDINJ2 (No. 2 INJECTOR)Drives No. 2 injector
5BRNINJ1 (No. 1 INJECTOR)Drives No. 1 injector
6GRNFANC (RADIATOR FAN CONTROL)Drives radiator fan relayWith radiator fan running: about 0 V
With radiator fan stopped: battery voltage
7*2GRN/WHTDNLS+ (CVT DRIVEN PULLEY CONTROL VALVE +SIDE)Drives CVT driven pulley control valveWith ignition switch ON (II): pulsing signal
8RED/WHTECT (ENGINE COOLANT TEMPERATURE SENSOR)Detects ECT sensor signalWith the ignition switch ON (II): about 0.1-4.8 V
(depending on engine coolant temperature)
9*8BLU/BLKVTPSW (VTEC OIL PRESSURE SWITCH)Detects VTEC oil pressure switch signalWith engine at low engine speed: about 0 V
With engine at high engine speed: battery voltage
11*3RED/WHTMIND (M INDICATOR)Drives M indicator lightWith M indicator light turned ON: about 6 V
With M indicator light turned OFF: 0 V voltage
12*2LT GRNSIND (S INDICATOR)Drives S indicator lightWith S indicator light turned ON: about 6 V
With S indicator light turned OFF: 0 V voltage
13WHT/REDALTF (ALTERNATOR FR SIGNAL)Detects alternator FR signalWith engine running: about 0-5 V
(depending on electrical load)
14*6PNKEGR (EXHAUST GAS RECIRCULATION (EGR) VALVE)Drives EGR valveWith EGR operating: duty controlled
With EGR not operating: about 0 V
15GRN/YELVTS (VTEC SOLENOID VALVE)Drivers VTEC solenoid valveAt idle: about 0V
16*2YELSCLS+ (CVT START CLUTCH PRESSURE CONTROL VALVE +SIDE)Drives CVT start clutch pressure control valveWith ignition switch ON (II): pulsing signal
17RED/YELIAT (INTAKE AIR TEMPERATURE SENSOR)Detects IAT sensor signalWith ignition switch ON (II): about 0.1-4.8 V
(depending on intake air temperature)
18WHT/GRNALTC (ALTERNATOR CONTROL)Sends alternator control signalWith engine running: about 0-5 V
(depending on electrical load)
19*3LT GRN/REDS-DN (DOWN SHIFT SWITCH)Detects downshift switch signalSteering shift switch pushed toward downshift position (marked with -): 0 V
Steering shift switch in neutral position: about 5 V
20*3YELS-UP (UP SHIFT SWITCH)Detects upshift switch signalSteering shift switch pushed toward upshift position (marked with +): 0 V
Steering shift switch in neutral position: about 5 V
21RED/YELPCS (EVAPORATIVE EMISSION (EVAP) CANISTER PURGE VALVE)Drives EVAP canister purge valveWith engine running, engine coolant below 65°C (149°F): about 0 V
With engine running, engine coolant above 65°C (149°F): duty controlled
24*2BLU/WHTDRLS+ (CVT DRIVE PULLEY CONTROL VALVE +SIDE)Drives CVT drive pulley control valveWith ignition switch ON (II): duty controlled

*2:CVT
*3:HONDA CVT+7SPEED MODE system
*6:Except IN, KH models
*8:KQ model

PCM Inputs and Outputs at Connector C (22P)*2

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1PNK/BLKDNLS- (CVT DRIVEN PULLEY CONTROL VALVE -SIDE)Drives CVT driven pulley control valve
3BLKPG (CVT2) (POWER GROUND CVT2)Ground for the PCM circuit
5BLKPG (CVT1) (POWER GROUND CVT1)Ground for the PCM circuit
6GRN/BLKINHSOL (INHIBITOR SOLENOID CONTROL)Drives inhibitor solenoidWith inhibitor solenoid ON: battery voltage
With inhibitor solenoid OFF: 0 V
7RED/BLUNDR (CVT DRIVE PULLEY SPEED SENSOR)Detects CVT drive pulley speed sensor signalWith ignition switch ON (II): 0 V or 5 V
8PNK/BLUSCLS- (CVT START CLUTCH PRESSURE CONTROL VALVE B -SIDE)Drives CVT start clutch pressure control valve
9BLU/WHTATPS (TRANSMISSION RANGE SWITCH S POSITION)Drives transmission range switch S position signalIn S position: 0 V
In any other position: about 5 V or battery voltage
10WHTATPR (TRANSMISSION RANGE SWITCH R POSITION)Detects transmission range switch R position signalIn R position: 0 V
In any other position: about 10 V
11BLUATPL (TRANSMISSION RANGE SWITCH L POSITION)Detects transmission range switch L position signalIn L position: 0 V
In any other position: about 10 V
12LT GRNATPNP (TRANSMISSION RANGE SWITCH NEUTRAL/PARK POSITION)Detects transmission range switch Neutral/Park position signalIn Park or Neutral: 0 V
In any other position: about 10 V
13*3YELMSW (MAIN SWITCH)Detects main switch
(7SPEED MODE) signal
Main switch (7SPPED MODE) pushed: 0 V
Main switch (7SPPED MODE) released: about 5 V
15WHTNDN (CVT DRIVEN PULLEY SPEED SENSOR)Detects CVT driven pulley speed sensor signalWith ignition switch ON (II): 0 V or 5 V
16GRN/YELDRLS- (CVT DRIVE PULLEY CONTROL VALVE -SIDE)Drives CVT drive pulley control valveWith ignition switch ON (II): pulses
20PNKATPD (TRANSMISSION RANGE SWITCH D POSITION)Detects transmission range switch D position signalIn D position: about 0 V
In any other position: about 5 V
22WHT/REDVEL1 (CVT SPEED SENSOR)Detects CVT speed sensorDepending on vehicle speed: pulses
When vehicle is stopped: about 0 V or about 5 V

*2:CVT
*3:HONDA CVT+7SPEED MODE system

ECM/PCM Inputs and Outputs at Connector E (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
1GRN/YELIMOFPR (IMMOBILIZER FUEL PUMP RELAY)Drives PGM-FI main relay 20 V for 2 seconds after turning ignition switch ON (II), then battery voltage
2*2WHT/REDSHO2S (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S), SENSOR 2)Detects secondary HO2S (sensor 2) signalWith throttle fully opened from idle with fully warmed up engine: above 0.6 V
With throttle quickly closed: below 0.4 V
3BRN/YELLG3 (LOGIC GROUND)Ground for the PCM control circuitLess than 0.1 V at all times
4PNKSG3 (SENSOR GROUND)Sensor groundLess than 0.1 V at all times
5GRN/WHTFUP (FUEL INJECTION SIGNAL)Sends fuel injection signal to gauge assemblyWith ignition switch ON (II): pulses
6*2BLK/WHTSHO2SHTC (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S) HEATER CONTROL)Drives secondary HO2S heaterWith ignition switch ON (II): battery voltage
With fully warmed up engine running: duty controlled
7RED/YELMRLY (PGM-FI MAIN RELAY)Drives PGM-FI main relay 1 Power source for the DTC memoryWith ignition switch ON (II): about 0 V
With ignition switch OFF: battery voltage
8*3BLU/WHTLED ADrives shift indicatorIn 7SPEED MODE:
  • in 1st, 2nd, 3rd and 7th: about 0.3 V
  • in 4th, 5th and 6th: about 5 V
9BLK/YELIG1 (IGNITION SIGNAL)Detects ignition signalWith ignition switch ON (II): battery voltage
With ignition switch OFF: about 0 V
11PNKDIND (D INDICATOR)Drives D indicator lightWith D indicator light turned ON: about 6 V
With D indicator light turned OFF: 0 V
12BLUTACDetects evaporator sensor signalWith ignition switch ON (II): about 0.1-4.8 V (depending on evaporator temperature)
13*2BLU/REDSLC (SHIFT LOCK CONTROL)Drives shift lock solenoidWith ignition switch ON (II), in Park position, brake pedal pressed, and accelerator pedal released: 0 V
14*7GRN/BLKACT TMP (A/C TEMPERATURE DIAL)Detects A/C Temperature dial signalWith ignition switch ON (II): about 0.5-4.5 V
(depending on A/C temperature dial)
15GRN/REDELD (ELECTRICAL LOAD DETECTOR (ELD))Detects ELD signalWith ignition switch ON (II): about 0.1-4.8 V (depending on electrical load)

*2:CVT
*3:HONDA CVT+7SPEED MODE system
*4:Except IN model
*7:Without heater

ECM/PCM Inputs and Outputs at Connector E (31P)

NOTE: Standard battery voltage is 12 V.

Terminal numberWire colorTerminal nameDescriptionSignal
18REDACC (A/C CLUTCH RELAY)Drives A/C clutch relayWith compressor ON: about 0 V
With compressor OFF: battery voltage
19*7RED/WHTVCC3 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON(II): about 5 V
With ignition switch OFF: about 0 V
20*3GRN/BLKLED CDrives shift indicatorIn 7SPEED MODE:
  • in 2nd, 4th, 6th and 7th: about 0.3 V
  • in 1st, 3rd and 5th: about 5 V
21*3RED/WHTLED BDrives shift indicatorIn 7SPEED MODE:
  • in 1st, 4th, 5th and 7th: about 0.3 V
  • in 2nd, 3rd and 6th: about 5 V
22WHT/BLKBKSW (BRAKE PEDAL POSITION SWITCH)Detects brake pedal position switch signalWith brake pedal released: about 0 V
With brake pedal pressed: battery voltage
23RED/WHTK-LINESends and receives scan tool signalWith ignition switch ON (II): battery voltage
24GRNMTRTWSends engine coolant temperature signalWith ignition switch ON (II): pulse
25BLU/YELVSSOUT (VEHICLE SPEED SENSOR (VSS) OUTPUT SIGNAL)Sends vehicle speed sensor signalDepending on vehicle speed: pulses
26BLUNEP (ENGINE SPEED PULSE)Outputs engine speed pulseWith engine running: pulses
27RED/BLUIMOCD (IMMOBILIZER CODE)Detects immobilizer signal
28BLU/WHTACS (A/C SWITCH SIGNAL)Detects A/C switch signalWith A/C switch ON: 0 V
With A/C switch OFF: about 5 V
29BRNSCS (SERVICE CHECK SIGNAL)Detects service check signalWith the service check signal shorted with the PGM Tester: about 0 V
With the service check signal opened: about 5 V
30RED/BLUWEN (WRITE ENABLE SIGNAL)Detects write enable signalWith ignition switch ON (II): about 0V
31GRN/ORNMIL (MALFUNCTION INDICATOR LAMP)Drives MILWith MIL turned ON: about 0 V
With MIL turned OFF: battery voltage

*3:HONDA CVT+7SPEED MODE system
*7:Without heater

Vacuum Hose Routing


Vacuum Distribution


Except L15A1, L15A5 engines

Vacuum Distribution


L15A1, L15A5 engines

PGM-FI System


The Programmed Fuel Injection (PGM-FI) system is a sequential multiport fuel injection system.

Air Conditioning (A/C) Compressor Clutch Relay

When the Engine Control Module (ECM)/Powertrain Control Module (PCM) receives a demand for cooling from the A/C system, it delays the compressor from being energized, and enriches the mixture to assure smooth transition to the A/C mode.

Alternator Control

The alternator signals the ECM/PCM during charging.

Barometric Pressure (BARO) Sensor

The BARO sensor is inside the ECM/PCM. It converts atmospheric pressure into a voltage signal that the ECM/ PCM use to modify the basic duration of the fuel injection discharge.

Camshaft Position (CMP) Sensor
(Top Dead Center (TDC) Sensor)

The CMP (TDC) sensor detects the position of the No. 1 cylinder as a reference for sequential fuel injection to each cylinder.


Crankshaft Position (CKP) Sensor

The CKP sensor detects engine speed and determines ignition timing and timing for fuel injection of each cylinder.

Engine Coolant Temperature (ECT) Sensor

The ECT sensor is a temperature dependent resistor (thermistor). The resistor of the thermistor decreases as the engine coolant temperature increases.

i-DSI System (Except L15A1, L15A5 engines)

The ECM/PCM controls the ignition phase gap between the front and rear spark plugs in accordance with the engine speed and the vacuum in the intake manifold.

Ignition Timing Control

The ECM/PCM contains the memory for basic ignition timing at various engine speeds and manifold absolute pressure. It also adjusts the timing according to engine coolant temperature.

Injector Timing and Duration

The ECM/PCM contains the memory for basic discharge duration at various engine speeds and manifold pressures. The basic discharge duration, after being read out from the memory, is further modified by signals sent from various sensors to obtain the final discharge duration.
By monitoring long term fuel trim, the ECM/PCM detects long term malfunctions in the fuel system, and will set a Diagnostic Trouble Code (DTC).

Intake Air Temperature (IAT) Sensor

The IAT sensor is a temperature dependant resistor (thermistor). The resistance of the thermistor decreases as the intake air temperature increases.

Knock Sensor

The knock control system adjusts the ignition timing to minimize knock.


Manifold Absolute Pressure (MAP) Sensor

The MAP sensor converts manifold absolute pressure into electrical signals to the ECM/PCM.

Primary Heated Oxygen Sensor (Primary HO2S)

The primary HO2S detects the oxygen content in the exhaust gas and sends signals to the ECM/PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The primary HO2S is installed in the exhaust manifold. By controlling the air fuel ratio with primary HO2S and secondary HO2S, the deterioration of the primary HO2S can be evaluated by its feedback period. When the feedback period exceeds a certain value during stable driving conditions, the sensor is considered deteriorated and the ECM/PCM sets a DTC.

Secondary Heated Oxygen Sensor (Secondary HO2S)

The secondary HO2S detects the oxygen content in the exhaust gas downstream of the Three Way Catalytic Converter (TWC) and sends signals to the ECM/PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The secondary HO2S is installed in the TWC.

Starting Control

When the engine is started, the ECM/PCM provides a rich mixture by increasing injector duration.

Throttle Position (TP) Sensor

The TP sensor is a potentiometer connected to the throttle valve shaft. As the throttle position changes, the sensor varies the signal voltage to the ECM/PCM. The TP sensor is not replaceable apart from the throttle body.

Vehicle Speed Sensor (VSS) (M/T model only)

The VSS is driven by the differential. It generates a pulsed signal from an input of 5 volts. The number of pulses per minute increases/decreases with the speed of the vehicle.

Idle Mixture Adjuster (IMA) (IN model)

The idle mixture adjuster (IMA) is selected resistance device used to control idle mixture.

VTEC System (L15A1 engine)







Idle Control System


When the engine is cold, the A/C compressor is on, the transmission is in gear, the brake pedal is pressed, the power steering load is high, or the alternator is charging, the ECM/PCM controls current to the Idle Air Control (IAC) valve to maintain the correct idle speed. Refer to the System Diagram to see the functional layout of the system.

Brake Pedal Position Switch

The brake pedal position switch signals the ECM/PCM when the brake pedal is pressed.

Idle Air Control (IAC) Valve

To maintain the proper idle speed, the IAC valve changes the amount of air bypassing the throttle body in response to an electrical signal from the ECM/PCM.

Fuel Supply System


Fuel Cut-off Control

During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at speeds over 900 rpm (min-1). Fuel cut-off action also occurs when engine speed exceeds 6,200 rpm (min-1), regardless of the position of the throttle valve, to protect the engine from over-revving. When the vehicle is stopped, the PCM cuts the fuel at engine speeds over 6,200 rpm (min-1).

Fuel Pump Control

When the ignition is turned on, the ECM/PCM grounds the PGM-FI main relay which feeds current to the fuel pump for 2 seconds to pressurize the fuel system. With the engine running, the ECM/PCM grounds the PGM-FI main relay and feeds current to the fuel pump. When the engine is not running and the ignition is on, the ECM/PCM cuts ground to the PGM-FI main relay which cuts current to the fuel pump.

PGM-FI Main Relay 1 and 2

The PGM-FI relay consists of two separate relays. The PGM-FI main relay 1 is energized whenever the ignition switch is ON (II) which supplies battery voltage to the ECM/PCM, power to the injectors, and power for the PGM-FI main relay 2. The PGM-FI main relay 2 is energized to supply power to the fuel pump for 2 seconds when the ignition switch is turned ON (II), and when the engine is running.

Intake Air System


Refer to the System Diagram to see the functional layout of the system.

Throttle Body

The throttle body is a single-barrel side draft type. The lower portion of the IAC valve is heated by engine coolant from the cylinder head.

Catalytic Converter System


Three Way Catalytic Converter (TWC)

The TWC converts hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO2), dinitrogen (N2), and water vapor.

Positive Crankcase Ventilation (PCV) System


The PCV valve prevents blow-by gasses from escaping into the atmosphere by venting them into the intake manifold.

Evaporative Emission (EVAP) Control System


Refer to the System Diagram to see the functional layout of the system.

EVAP Canister

The EVAP canister temporarily stores fuel vapor from the fuel tank until it can be purged back into the engine and burned (refer to the System Diagram to see the functional layout of the system).

EVAP Canister Purge Valve

When the engine coolant temperature is below 70°C (158°F), the ECM/PCM turns off the EVAP canister purge valve which cuts vacuum to the EVAP canister.

Idle Control System Diagram


The idle speed of the engine is controlled by the Idle Air Control (IAC) valve:

Intake Air System Diagram


This system supplies air for engine needs. A resonator in the intake air pipe provides additional silencing as air is drawn into the system.

Exhaust Gas Recirculation (EGR) System Diagram


The EGR system reduces oxides of nitrogen (NOx) emissions by recirculating exhaust gas through the EGR valve and the intake manifold into the combustion chambers. The ECM/PCM memory includes the ideal EGR valve position for varying operating conditions.

The EGR valve position sensor detects the amount of EGR valve lift and sends it to the ECM/PCM. The ECM/PCM then compares it with the ideal lift in its memory (based on signals sent from other sensors). If there is any difference between the two, the ECM/PCM cuts current to the EGR valve.




Evaporative Emission (EVAP) Control Diagram


The EVAP controls minimize the amount of fuel vapor escaping to the atmosphere. Vapor from the fuel tank is temporally stored in the EVAP canister until it can be purged from the EVAP canister into the engine and burned.





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