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Honda Fit/Jazz - Fuel and Emissions System Description (With ETCS)

Fuel and Emissions System Description

Electronic Control System


The functions of the fuel and emission control systems are managed by the engine control module (ECM).

Fail-safe Function

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

Self-diagnosis

When an abnormality occurs in the signal from a sensor, the ECM 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 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 stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and ON (II) again, the ECM informs the driver by turning on the MIL.

Self Shut Down (SSD) Mode

After the ignition switch is turned off, ECM stays ON (Up to 10 seconds).
If the ECM connector is disconnected during this mode, ECM may be damaged.
If you need to disconnet the ECM connector, disconnect the negative cable from the battery, or wait for 10 seconds after turning the ignition switch off.

ECM Inputs and Outputs at Connector No. 1 (9P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
44BRNPG1 (POWER GROUND)Ground for ECM circuitLess than 1.0 V at all times
55BRNPG2 (POWER GROUND)Ground for ECM circuitLess than 1.0 V at all times
77WHT/REDUBD (POWER SOURCE)Power source for ECM circuitBattery voltage at all times
88BRN/YELLG3 (LOGIC GROUND)Ground for ECM circuitLess than 1.0 V at all times

ECM Inputs and Outputs at Connector No. 3 (52P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
130BRN/YELCKPG (CRANKSHAFT POSITION (CKP) SENSOR GROUND)Ground for CKP sensorLess than 1.0 V at all times
332BLU/REDVCC4 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF:
about 0 V
433YEL/GRNVCC3 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF:
about 0 V
534WHT/GRNALTC (ALTERNATOR CONTROL)Sends alternator control signalWith engine running and fully warmed up:
batter voltage (depending on electrical load)
635GRNCMP (CAMSHAFT POSITION (CMP) SENSOR)Detects CMP sensor signalWith engine running: pulses
736WHT/BLKIGPLS3E (No. 3 REAR IGNITION COIL PULSE)Drives No. 3 rear ignition coilWith ignition switch ON (II):
about 0 V
With engine running: pulses
837WHT/GRNIGPLS2E (No. 2 REAR IGNITION COIL PULSE)Drives No. 2 rear ignition coil
938WHTIGPLS1I (No. 1 FRONT IGNITION COIL PULSE)Drives No. 1 front ignition coil
1039BRNINJ1 (No. 1 INJECTOR)Drives No. 1 injectorAt idle: duty controlled
1140BLUINJ3 (No. 3 INJECTOR)Drives No. 3 injector
1241YELINJ4 (No. 4 INJECTOR)Drives No. 4 injector
1342REDINJ2 (No. 2 INJECTOR)Drives No. 2 injector
1443BLUCKP (CRANKSHAFT POSITION (CKP) SENSOR)Detects CKP sensor signalWith engine running: pulses
1645YEL/BLUVCC2 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF:
about 0 V
1746YEL/REDVCC1 (SENSOR VOLTAGE)Provides sensor voltageWith ignition switch ON (II): about 5 V
With ignition switch OFF:
about 0 V
1948WHT/REDALTF (ALTERNATOR FR SIGNAL)Detects alternator FR signalWith engine running:
about 0-5 V (depending on electrical load)

ECM Inputs and Outputs at Connector No. 3 (52P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
2049WHTIGPLS1E (No. 1 REAR IGNITION COIL PULSE)Drives No. 1 rear ignition coilWith ignition switch ON (II):
about 0 V
With engine running: pulses
2150WHT/BLUIGPLS4E (No. 4 REAR IGNITION COIL PULSE)Drives No. 4 rear ignition coil
2251WHT/BLKIGPLS3I (No. 3 FRONT IGNITION COIL PULSE)Drives No. 3 front ignition coil
2352WHT/GRNIGPLS2I (No. 2 FRONT IGNITION COIL PULSE)Drives No. 2 front ignition coil
2453WHT/BLUIGPLS4I (No. 4 FRONT IGNITION COIL PULSE)Drives No. 4 front ignition coil
2554GRNFANC (RADIATOR FAN CONTROL)Drives radiator fan relayWith radiator fan running:
about 0 V
With radiator fan stopped: battery voltage
2655YEL/BLUPCS (EVAPORATIVE EMISSION (EVAP) CANISTER PURGE VALVE)Drives EVAP canister purge valveWith engine running, engine coolant below 40 °C (104 °F): battery voltage
With engine running, engine coolant above 40 °C (104 °F): duty controlled
2958GRN/BLKSG3 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
3059GRN/BLKSG4 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
3160GRN/WHTSG1 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
3261GRN/YELPHO2SG (PRIMARY HEATED OXYGEN SENSOR (PRIMARY HO2S, SENSOR 1) GROUND)Ground for primary HO2S (sensor 1)Less than 1.0 V at all times
3362GRN/BLKSG2 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
3463GRNAPSA (ACCELERATOR PEDAL POSITION (APP) SENSOR A)Detects APP sensor A signalWith ignition switch ON (II) and accelerator pedal pressed:
about 4.1 V
With ignition switch ON (II) and accelerator pedal released:
about 0.6 V
3564GRN/REDMAP (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)
3665BLUTPSA (THROTTLE POSITION (TPS) SENSOR A)Detects TPS sensor A signalWith ignition switch ON (II) and throttle fully open: about 4.7 V
With ignition switch ON (II) and throttle fully closed: about 0.1 V

ECM Inputs and Outputs at Connector No. 3 (52P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
3968WHT/BLKEGRP (EXHAUST GAS RECIRCULATION (EGR) VALVE POSITION SENSOR)Detects EGR valve position sensor signalWith engine running:
about 1.2-2.0 V (depending on EGR valve lift)
4069YELKS1 (KNOCK SENSOR)Detects knock sensor signalWith engine knocking: pulses
4170GRY/REDKS2 (KNOCK SENSOR)Ground for knock sensorLess than 1.0 V at all times
4271BLKVSSG (VEHICLE SPEED SENSOR (VSS) GROUND)Ground for VSSLess than 1.0 V at all times
4473WHT/GRNVSS (VEHICLE SPEED SENSOR (VSS))Detects VSS signalWith ignition switch ON (II) and front wheels rotating: cycles 0 V-about 5 V or battery voltage
4675BRN/YELCMPG (CAMSHAFT POSITION (CMP) SENSOR GROUND)Ground for CMP sensorLess than 1.0 V at all times
4776WHTPHO2S (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
4877GRN/BLKSG5 (SENSOR GROUND)Sensor groundLess than 1.0 V at all times
4978YELTPSB (THROTTLE POSITION (TPS) SENSOR B)Detects TPS sensor B signalWith ignition switch ON (II) and throttle fully open: about 4.9 V
With ignition switch ON (II) and throttle fully closed: about 0.1 V
5079REDAPSB (ACCELERATOR PEDAL POSITION (APP) SENSOR B)Detects APP sensor B signalWith ignition switch ON (II) and accelerator pedal pressed:
about 2.3 V
With ignition switch ON (II) and accelerator pedal released:
about 0.2 V
5180RED/YELIAT (INTAKE AIR TEMPERATURE (IAT) SENSOR)Detects IAT sensor signalWith ignition switch ON (II): about 0.1-4.8 V (depending on intake air temperature)
5281RED/WHTECT (ENGINE COOLANT TEMPERATURE (ECT) SENSOR)Detects ECT sensor signalWith ignition switch ON (II): about 0.1-4.8 V (depending on engine coolant temperature)

ECM Inputs and Outputs at Connector No. 4 (40P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
182GRN/WHTFUP (FUEL INJECTION SIGNAL)Sends fuel injection signal to gauge assemblyWith ignition switch ON (II): pulses
283GRNMTRTWSends engine coolant temperature signalWith ignition switch ON (II): pulses
585RED/WHTK-LINESends and receives HDS signalWith ignition switch ON (II): pulses or battery voltage
687RED/BLUIMOCD (IMMOBILIZER CODE)Detects immobilizer signal
990GRN/YELIMOFPR (IMMOBILIZER FUEL PUMP RELAY)Drives PGM-FI main relay 2About 0 V for 2 seconds after turning ignition switch ON (II), then battery voltage
1091GRN/ORNMIL (MALFUNCTION INDICATOR LAMP)Drives MILWith MIL turned ON: about 0 V
With MIL turned OFF: battery voltage
1192RED/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
1798BRN/YELLG1 (LOGIC GROUND)Ground for ECM circuitLess than 1.0 V at all times
1899BLUNEP (ENGINE SPEED PULSE)Outputs engine speed pulseWith engine running: pulses
19100REDACC (A/C CLUTCH RELAY)Drives A/C clutch relayWith compressor ON: about 0 V
With compressor OFF: battery voltage
21102PNKSHO2SG (SECONDARY HEATED OXYGEN SENSOR (SECONDARY HO2S), SENSOR 2 GROUND)Ground for secondary HO2S (sensor 2)Less than 1.0 V at all times
22103WHT/BLUBKPD (BRAKE PEDAL POSITION SWITCH)Detects brake pedal position switch signalWith ignition switch ON (II) and brake pedal released: battery voltage
With ignition switch ON (II) and brake pedal pressed: about 0 V
23104WHT/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: about 0.6 V
With throttle quickly closed: below 0.4 V

ECM Inputs and Outputs at Connector No. 4 (40P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
27108YEL/BLKIG1 (IGNITION SIGNAL)Detects ignition signalWith ignition switch ON (II): battery voltage
With ignition switch OFF:
about 0 V
31112BLU/WHTACS (A/C SWITCH SIGNAL)Detects A/C switch signalWith A/C switch ON: about 0 V
With A/C switch OFF: about 5 V
32113BRNSCS (SERVICE CHECK SIGNAL)Detects service check signalWith the service check signal shorted with the HDS: about 0 V
With the service check signal opened: about 5 V battery voltage
34115GRN/REDELD (ELECTRICAL LOAD DETECTOR (ELD))Detects ELD signalWith ignition switch ON (II): about 0.1-4.8 V (depending on electrical load)
36117WHT/BLKBKSW (BRAKE PEDAL POSITION SWITCH)Detects brake pedal position switch signalWith brake pedal released: about 0 V
With brake pedal pressed: battery voltage
39120BRN/YELLG2 (LOGIC GROUND)Ground for ECM circuitLess than 1.0 V at all times

ECM Inputs and Outputs at Connector No. 5 (9P)

NOTE: Standard battery voltage is 12 V.

ECM Terminal numberPin Box Terminal numberWire colorTerminal nameDescriptionSignal
1122REDETC1 (ELECTRIC THROTTLE CONTROL SYSTEM 1)Drives throttle actuatorWith throttle valve moving: duty controlled
With throttle valve not moving: not specified
2123GRNETC2 (ELECTRIC THROTTLE CONTROL SYSTEM 2)Drives throttle actuatorWith throttle valve moving: duty controlled
With throttle valve not moving: not specified
3124BLU/REDEGR (EXHAUST GAS RECIRCULATION (EGR) VALVE)Drives EGR valveWith EGR operating: duty controlled
With EGR not operating:
about 0 V
4125BLK/WHTSO2SHTC (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
5126GRN/BLKEGRG (EXHAUST GAS RECIRCULATION (EGR) VALVE GROUND)Ground for EGR valveLess than 1.0 V at all times
7128YEL/BLKIGP1 (POWER SOURCE)Power source for ECM circuitWith ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
8129YEL/BLKIGP2 (POWER SOURCE)Power source for ECM circuitWith ignition switch ON (II): battery voltage
With the ignition switch OFF: about 0 V
9130BLK/WHTPO2SHTC (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

Vacuum Hose Routing









Vacuum Distribution





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) 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 during charging.

Barometric Pressure (BARO) Sensor

The BARO sensor is inside the ECM. It converts atmospheric pressure into a voltage signal that modifies the basic duration of the fuel injection discharge.

Camshaft Position (CMP) Sensor

The CMP 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

The ECM 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 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 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 detects long term malfunctions in the fuel system, and will set a diagnostic trouble code (DTC).

Intake Air Temperature/Manifold Absolute Pressure (IAT/MAP) Sensor

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

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

Knock Sensor

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

Primary Heated Oxygen Sensor (Primary HO2S)

The primary HO2S detects the oxygen content in the exhaust gas and sends signals to the ECM 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 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 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 provides a rich mixture by increasing injector duration.

Vehicle Speed Sensor (VSS)

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.

Electronic Throttle Control System


The throttle is electronically controlled by the electronic throttle control system. Refer to the system diagram to see the functional layout of the system.

Idle control: When the engine is idling, the ECM controls the throttle actuator to maintain the proper idle speed according to engine loads.

Acceleration control: When the accelerator pedal is pressed, the ECM opens the throttle valve depending on the accelerator pedal position (APP) sensor signal.

Accelerator Pedal Position (APP) Sensor

As the accelerator pedal position changes, the sensor varies the signal voltage to the ECM.

Throttle Body

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

Idle Control System


When the engine is cold, the A/C compressor is on, the transmission is in gear, the brake pedal is pressed, or the alternator is charging, the ECM controls current to the throttle actuator to maintain the correct idle speed.

Brake Pedal Position Switch

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

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 1,160 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 ECM cuts the fuel at engine speeds over 6,200 rpm (min-1).

Fuel Pump Control

When the ignition is turned on, the ECM 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 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 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. PGM-FI main relay 1 is energized whenever the ignition switch is ON (II) which supplies battery voltage to the ECM, power to the injectors, and power for PGM-FI main relay 2. 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.

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.

Exhaust Gas Recirculation (EGR) System


Refer to the system diagram to see the functional layout of the system.

EGR Valve

The EGR valve lowers peak combustion temperatures and reduces oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the intake manifold and into the combustion chambers.

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 40 °C (104 °F), the ECM turns off the EVAP canister purge valve which cuts vacuum to the EVAP canister.

Electronic Throttle Control System Diagram


The electronic throttle control system consists of the throttle actuator, throttle position (TP) sensor, accelerator pedal position (APP) sensor, and the ECM. The throttle is electronically controlled by this 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 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. The ECM 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 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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