Fuel System & Emissions Systems Acura RSX I

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Intermittent Failures

The term "intermittent failure" means a system may have had a failure, but it checks OK now. If the malfunction indicator lamp (MIL) on the dash does not come on, check for poor connections or loose pins at all connectors related to the circuit that you are troubleshooting. If the MIL was on but then went out, the original problem may have been intermittent.

Opens and Shorts

"Open" and "Short" are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't work at all. With complex electronics (such as ECMs and PCMs) this can sometimes mean something works, but not the way it's supposed to.

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1. Start the engine and check the MIL (A). NOTE: If the ignition switch is turned ON (II), and the engine is not started, the MIL will stay on for 15-20 seconds (see «HOW TO SET READINESS CODES»(/acura/rsx/i-2001-2004/remont/auxiliary-emission-control-systems/#fuel-system-emissions-systems) ).
2. If the MIL stays on, connect the HDS or an OBD II scan tool to the data link connector (DLC) (A) located under the driver's side of the dashboard.
3. Turn the ignition switch ON (II).
4. Check the diagnostic trouble code (DTC) and note it. Also check the freeze data. Refer to the indicated DTC's troubleshooting, and begin the appropriate troubleshooting procedure. NOTE: Freeze data indicates the engine conditions when the first malfunction, misfire, or fuel trim malfunction was detected. The HDS or a scan tool can read the DTC, freeze data, current data, and other engine control module (ECM) powertrain control module (PCM) data. For specific operations, refer to the user's manual that came with the HDS or a scan tool.
5. If no DTCs are found, go to MIL troubleshooting (see «MIL CIRCUIT TROUBLESHOOTING»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#pgm-fi-system) ).

If the MIL did not stay on

If the MIL did not stay on, but there is a driveability problem, do the symptom troubleshooting.

If you can't duplicate the DTC

Some of the troubleshooting requires you to reset the ECM/PCM and try to duplicate the DTC. If the problem is intermittent and you can't duplicate the code, do not continue through the procedure. To do so will only result in confusion and possibly, a needlessly replaced ECM/PCM.

ECM/PCM Reset (2002-2004 Models)

You can reset the ECM/PCM in either of two ways

Note. After resetting the ECM/PCM do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).

Reset the ECM/PCM with the OBD II scan tool or the HDS

1. Turn the ignition switch ON (II). Do not start the engine.
2. Use the OBD II scan tool or the HDS to reset the ECM/PCM. NOTE: For the specific operations, refer to the user's manual that came with the OBD II scan tool or the HDS .

Scheme 19

1. Turn the ignition switch OFF.
2. Remove the No. 6 ECU (ECM/PCM) (15 A) fuse (A) from the underhood fuse/relay box (B) for 10 seconds.

HDS Clear Command (2005-2006 Models)

The ECM/PCM stores various specific data to correct the system even when there is no electrical power such as the battery negative terminal or No. 6 Fl ECU (ECM/PCM) (20 A) fuse are disconnected. Stored data based on failed parts should be cleared by using the "CLEAR COMMAND" of the HDS, if parts are replaced.

The HDS has three kinds of clear commands to meet this purpose. They are DTC clear, ECM/PCM reset, and CKP pattern clear. DTC clear command erases all stored DTC codes, freeze data and readiness codes. This must be done with the HDS after reproducing the DTC during troubleshooting.

The ECM/PCM reset command erases all stored DTC codes, freeze data, readiness codes, and all specific data to correct the system except CKP pattern. If the CKP pattern data in ECM/PCM was cleared, you must do the CKP pattern learn procedure. The CKP pattern clear command erases only CKP pattern data. This command is for repair of a misfire or the CKP sensor.

Scan Tool Clear Command

If you are using a generic scan tool to clear commands, be aware that there is only one setting for clearing the ECM/PCM, and it clears all commands at the same time (CKP pattern learn, idle learn, readiness codes, freeze data, on-board snapshot, and DTCs). After you clear all commands, you then need to do these procedures, in this order: ECM/PCM idle learn procedure, 2002-2004 models (see ECM/PCM IDLE LEARN PROCEDURE ), 2005-2006 models (see ECM/PCM IDLE LEARN PROCEDURE ); CKP pattern learn procedure (2005-2006 models); Test-drive to set readiness codes to complete (see HOW TO SET READINESS CODES ).

DTC Clear (2005-2006 Models)

1. Clear the DTC with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II). Wait 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the DLC.

ECM/PCM Reset (2005-2006 Models)

This command clears stored specific data from each vehicle such as DTCs, freeze data, and readiness codes. It does not clear CKP PATTERN data.

1. Reset the ECM/PCM with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II). Wait 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the DLC.
5. Do the ECM/PCM idle learn procedure (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ).

CKP Pattern Clear/CKP Pattern Learn (2005-2006 Models)

Note. The ECT needs to be at 176°F (80°C) or higher.

1. Clear the CKP PATTERN CLEAR with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait 30 seconds.
4. Test-drive the vehicle on a level road: decelerate (with the throttle fully closed) from an engine speed of 2,500 RPM to 1,000 RPM with the A/T 2nd gear in M position, or the M/T in 2nd or 3rd gear.
5. Stop the vehicle. Do not turn the ignition off.
6. Select the ALL DATA LIST in the DATA LIST MENU of the HDS.
7. Check the status of PULSER F/B LEARN. If it is set to NG, the enable criteria was probably not met; repeat the procedure from the beginning.

How to End a Troubleshooting Session (required after any troubleshooting)

1. Reset the ECM/PCM with the HDS.
2. Do the ECM/PCM idle learn procedure. 2002-2004 models (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ). 2005-2006 models (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ).
3. Turn the ignition switch OFF.
4. Disconnect the HDS or the OBD II scan tool from the DLC. NOTE: The ECM/PCM is part of the immobilizer system. If you replace the ECM/PCM, it will have a different immobilizer code. In order for the engine to start, you must rewrite the immobilizer code with the HDS.

How to Troubleshoot Circuits at the ECM/PCM

Special Tools Required

1. Digital multimeter KS-AHM-32-003 (1) or a commercially available digital multimeter
2. Backprobe set 07SAZ-001000A (2)

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1. Connect the backprobe adapters (A) to the stacking patch cords (B), and connect the cords to a digital multimeter (C).
2. Using the wire insulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire side until it touches the end of the wire terminal.
3. If you cannot get to the wire side of the connector or the wire side is sealed (A), disconnect the connector and probe the terminals (B) from the terminal side. Do not force the probe into the connector. NOTE: Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.

ECM/PCM Updating and Substitution for Testing

Special Tools Required

Honda interface module (HIM) EQS05A35570

Use this procedure when you have to substitute a known-good ECM/PCM in a troubleshooting procedure. Update the ECM/PCM only if the ECM/PCM does not have the latest software loaded.

Note. Do not turn the ignition switch OFF while updating the ECM/PCM. If you turn the ignition switch OFF before completion, the ECM/PCM can be damaged.

How to Update the ECM/PCM

Note. To ensure the latest program is installed, do an ECM/PCM update whenever the ECM/PCM is substituted or replaced. You can not update an ECM/PCM with the program it already has. It will only accept a new program. Before you update the ECM/PCM, make sure the vehicle's battery is fully charged. To prevent ECM/PCM damage, do not operate anything electrical (audio system, brakes, A/C, power windows, moonroof, door locks, etc.) during the update. If you need to diagnose the Honda interface module (HIM) because the HIM's red (#3) light came on or was flashing during the update, leave the ignition switch in the ON (II) position when you disconnect the HIM from the data link connector (DLC). This will prevent ECM/PCM damage.

Scheme 22

1. Turn the ignition switch ON (II). Do not start the engine.
2. Connect the HDS or the Honda interface module (HIM) to the data link connector (DLC) (A) located under the driver's side of the dashboard.
3. Do the ECM/PCM update procedure as described on the HIM label or in the ECM/PCM update system.
4. Do the ECM/PCM idle learn procedure, 2002-2004 models (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ), 2005-2006 models (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ).
5. 2005-2006 models: Clear the CKP pattern with the HDS while the engine is stopped (see «ECM/PCM RESET (2005-2006 MODELS)»(/acura/rsx/i-2001-2004/remont/auxiliary-emission-control-systems/#fuel-system-emissions-systems__ecmpcm-reset-2005-2006-models) ).

How to Substitute the ECM/PCM (2002-2004 Models)

1. Remove the ECM/PCM from the vehicle.
2. Install a known-good ECM/PCM.
3. Rewrite the immobilizer code with the ECM/PCM replacement procedure from the HDS; it allows you to start the engine.
4. After completing your tests, install the original ECM/PCM and rewrite the immobilizer code with the ECM/PCM replacement procedure with the HDS.
5. Do the ECM/PCM idle learn procedure (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ).

Scheme 23

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1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
2. Jump the SCS line with the HDS.
3. Remove the passenger's dashboard lower cover (A) (see «PASSENGER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION»(/acura/rsx/i-2001-2004/remont/exteriorinterior-trim/#dashboard) ).
4. Disconnect the ECM/PCM connectors (B).
5. Remove the ECM/PCM mounting bolts (C) and the ECM/PCM (D).
6. Install the ECM/PCM in the reverse order of removal.
7. Open the SCS with the HDS.
8. Turn the ignition switch ON (II). NOTE: DTC: P0630 "VIN Not Programmed or Mismatch" may be stored because the VIN has not been programmed into the ECM/PCM; ignore it, and continue this procedure.
9. Input the VIN to the ECM/PCM with the HDS.
10. Rewrite the immobilizer code with the ECM/PCM replacement procedure in the HDS; it allows you to start the engine.
11. Reset the ECM/PCM with the HDS.
12. Do the ECM/PCM idle learn procedure (see «ECM/PCM IDLE LEARN PROCEDURE»(/acura/rsx/i-2001-2004/remont/testing-diagnostics/#idle-control-system) ).
13. Do the CKP pattern learn procedure.

OBD Status (2005-2006 Models)

The OBD status shows the current system status of each DTC and all of the parameters. This function is used to see if the technician's repair was successfully finished. The results of diagnostic tests for the DTC are displayed as

1. PASSED: On board diagnosis is successfully finished.
2. FAILED: On board diagnosis has finished but failed.
3. EXECUTING: The vehicle is in enable criteria conditions for the DTC and the on board diagnosis is running.
4. NOT COMPLETED: The on board diagnosis was running but is out of the enable conditions of the DTC.
5. OUT OF CONDITION: The vehicle has stayed out of the enable conditions of the DTC.

2002-2004 Models

SYMPTOM CHART

SYMPTOM CHART

DATA DESCRIPTION CHART

DATA DESCRIPTION CHART

2005-2006 Models

DATA DESCRIPTION CHART

DATA DESCRIPTION CHART

DATA DESCRIPTION CHART

When the vehicle has one of these symptoms, check the diagnostic trouble code (DTC) with a scan tool. If there is no DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.

SYMPTOM TROUBLESHOOTING

When the vehicle has one of these symptoms, check for a diagnostic trouble code (DTC) with the HDS. If there is no DTC, do the diagnostic procedure for the symptom, in the sequence listed, until you find the cause.

SYMPTOM TROUBLESHOOTING

ECM/PCM Data (2002-2004 Models)

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

Note. The "operating values" listed are approximate and may vary depending on the environment and the individual vehicle. Unless noted otherwise, "at idle speed" means idling with the engine completely warmed up, A/T in Park or neutral, M/T in neutral position, and the A/C and all accessories turned off.

SYMPTOM TROUBLESHOOTING

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.

Self-diagnosis

The ECM/PCM detects a failure of a signal from a sensor or from another control unit and stores a Temporary DTC or a DTC. Depending on the failure, a DTC is stored whether in the first or the second drive cycle. When a DTC is stored, the ECM/PCM turns on the malfunction indicator lamp (MIL) by supplying ground to the MIL circuit.

1. One Drive Cycle Detection Method When an abnormality occurs in the signal from a sensor or from another control unit, the ECM/PCM stores a DTC and turns on the MIL.
2. Two Drive Cycle Detection Method When an abnormality occurs in the signal from a sensor or from another control unit in first drive cycle, the ECM/PCM stores a Temporary DTC. The MIL does not come on at this time. If the failure continues in the second drive cycle, the ECM/PCM stores a DTC and turns on the MIL.

Fail-safe Function

When an abnormality occurs in the signal from a sensor or from another control unit, the ECM/PCM ignores that signal, stores a DTC and turns on the MIL. The ECM/PCM will use a pre-programmed value, for that sensor, which allows the engine to continue running.

MIL Bulb Check and Readiness Code Condition

When the ignition switch is turned ON (II), the ECM/PCM supplies ground to the MIL circuit for about 15 to 20 seconds to check the bulb condition. If any readiness codes are not set to complete, the MIL flashes five times. If all readiness codes are set to complete, the MIL goes out.

Self Shut Down (SSD) Mode

After the ignition switch is turned OFF, the ECM/PCM stays on (up to 15 minutes). If the ECM/PCM connector is disconnected during this time, the ECM/PCM may be damaged. To cancel this mode, disconnect the negative cable from the battery or jump the SCS line with the HDS after the ignition switch is turned OFF.

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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 ECM/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.

Air Fuel Ratio (A/F) Sensor

The A/F Sensor operates over a wide air/fuel range. The A/F Sensor is installed upstream of the TWC, and sends signals to the ECM/PCM which varies the duration of fuel injection accordingly.

Scheme 57

Barometric Pressure (BARO) Sensor

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

Crankshaft Position (CKP) Sensor

The CKP sensor detects engine speed and is used by the ECM/PCM to determine ignition timing and timing for fuel injection of each cylinder as well as detecting engine misfire.

Scheme 58

Engine Coolant Temperature (ECT) Sensor

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

Scheme 59

Ignition Timing Control

The ECM/PCM contains the memory for basic ignition timing at various engine speeds and manifold absolute pressures. 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 sets a diagnostic trouble code (DTC).

Intake Air Temperature (IAT) Sensor

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

Scheme 60

Knock Sensor (KS)

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

Scheme 61

Malfunction Indicator Lamp (MIL) Indication (In relation to Readiness Codes)

The vehicle has certain "readiness codes" that are part of the on-board diagnostics for the emissions systems. If the vehicle's battery has been disconnected or gone dead, if the DTCs have been cleared, or if the ECM/PCM has been reset, these codes are reset. In some states, part of the emissions testing is to make sure these codes are complete. If all of them are not set to complete, the vehicle may fail the test, or the test cannot be finished.

To check if the readiness codes are set to complete, turn the ignition switch ON (II), but do not start the engine. The MIL will come on for 15-20 seconds. If it then goes off, the readiness codes are complete. If it flashes five times, one or more readiness codes are not complete. To set each code, drive the vehicle or run the engine as described in the procedures (see HOW TO SET READINESS CODES ).

Manifold Absolute Pressure (MAP) Sensor

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

Scheme 62

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 ECM/PCM compares the HO2S output with the A/F sensor output to determine catalyst efficiency. The secondary HO2S is located on the TWC.

Scheme 63

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.

Scheme 64

Camshaft Position (CMP) Sensor B

CMP sensor B detects the position of the No. 1 cylinder as a reference for sequential fuel injection to each cylinder.

Scheme 65

Vehicle Speed Sensor (VSS) (2002-2004 M/T models)

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.

Input Shaft (Mainshaft) Speed Sensor

This sensor detects mainshaft speed.

Scheme 66

Output Shaft (Countershaft) Speed Sensor (2005-2006 M/T models)

This sensor detects output shaft (countershaft) speed.

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1. The i-VTEC has a VTC (Variable Valve Timing Control) mechanism on the intake camshaft in addition to the usual VTEC. This mechanism improves fuel efficiency and reduces exhaust emissions at all levels of engine speed, vehicle speed, and engine load.
2. The VTEC mechanism changes the valve lift and timing by using more than one cam profile.
3. The VTC changes the phase of the intake camshaft via oil pressure. It changes the intake valve timing continuously.

Scheme 69

1. The VTC system makes continuous intake valve timing changes corresponding to the operation conditions.
2. It optimizes intake valve timing to allow the engine to produce maximum power.
3. Cam angle is advanced to obtain the EGR effect and reduce the pumping loss. The intake valve is closed quickly to reduce the entry of the air/fuel mixture into the intake port and improve the charging effect.
4. Reduces the cam advance at idle, stabilizes combustion, and reduces engine speed. If a malfunction occurs, VTC system control is disabled and the valve timing is fixed at the fully retarded position.

Scheme 70

1. The VTEC system changes the cam profile to correspond to the engine speed. It maximizes torque at low engine speeds and output at high engine speed.
2. The low lift cam is used at low engine speeds, and the high lift cam is used at high engine speeds.
3. The K20A2 and K20Z1 engines change both the intake and exhaust camshaft. Only the intake camshaft side has a VTEC mechanism on the K20A3 engine.

Scheme 71

Camshaft Position (CMP) Sensor A

CMP sensor A detects camshaft angle position for VTC system.

Scheme 72

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.

Scheme 73

Power Steering Pressure (PSP) Switch

The PSP switch signals the ECM/PCM when the power steering load is high.

Fuel Cut-off Control-2002-2004 Models

During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at speeds over 930 RPM (1,100 RPM) *1 . Fuel cut-off action also occurs when engine speed exceeds 6,900 RPM (8,100 RPM) *1 , regardless of the position of the throttle valve, to protect the engine from over-revving. When the vehicle is stopped, the ECM/PCM cuts the fuel at engine speeds over 5,500 RPM.

*1: K20A2 engine

Fuel Cut-off Control-2005-2006 Models

During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at speeds over 980 RPM (1,150 RPM) *2 . Fuel cut-off action also occurs when engine speed exceeds 6,500 RPM (7,800 RPM) *2 , regardless of the position of the throttle valve, to protect the engine from over-revving. When the vehicle is stopped, the ECM/PCM cuts the fuel at engine speeds over 3,500 RPM.

*2: K20Z1 engine

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. PGM-FI main relay 1 (FI MAIN) is energized whenever the ignition switch is ON (II) to supply battery voltage to the ECM/PCM, power to the injectors, and power for PGM-FI main relay 2 (FUEL PUMP). PGM-FI main relay 2 (FUEL PUMP) 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.

Intake Air Bypass Control Thermal Valve

When the engine is running during warm up, the intake air bypass control thermal valve sends air to the injector.

Scheme 74

Intake Manifold Tuning (IMT) (Intake Manifold Runner Control (IMRC)) Valve Position Sensor (K20A3 engine)

The IMT (IMRC) position sensor is a potentiometer connected to the IMT (IMRC) valve shaft. As the IMT (IMRC) valve position changes, the sensor varies the signal voltage to the ECM/PCM.

Scheme 75

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.

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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 (CO 2 ), di-nitrogen (N 2 ), and water vapor.

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Positive Crankcase Ventilation (PCV) System

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

K20A2/K20Z1 engines

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K20A3 engine

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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-2002-2004 Models

When the engine coolant temperature is below 149°F (65°C), the ECM/PCM turns off the EVAP canister purge valve which cuts vacuum to the EVAP canister.

EVAP Canister Purge Valve-2005-2006 Models

When the engine coolant temperature is below 140°F (60°C), the ECM/PCM turns off the EVAP canister purge valve which cuts vacuum to the EVAP canister.

Fuel Tank Pressure (FTP) Sensor

The FTP sensor converts fuel tank absolute pressure into an electrical input to the ECM/PCM.

2002-2004 models

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2005-2006 models

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EVAP Two Way Valve and EVAP Bypass Solenoid Valve (2002-2004 Models)

The EVAP two way valve is installed between the fuel tank and the EVAP canister.

The EVAP two way valve sends fuel vapor into the EVAP canister corresponding to the pressure inside the fuel tank and relieves excess vacuum by drawing fresh air in through the canister.

The EVAP bypass solenoid valve opens to bypass the two way valve when doing at the EVAP leak check.

Scheme 82

EVAP Canister Vent Shut Valve

The EVAP canister vent shut valve is on the EVAP canister.

The EVAP canister vent shut valve control the venting of the EVAP canister.

Scheme 83

*: This illustration shows 2005-2006 models.

Fuel Cap Warning Message (2005-2006 Models)

The ECM/PCM detects whether the fuel fill cap is loose or missing under certain conditions and alerts the driver by showing the information in the odometer/trip meter display. If the ECM/PCM detects a small volume leak, the MIL may come on during the second drive cycle and store a DTC.

First drive cycle

During the first drive cycle after a cold start, the ECM/PCM alerts the driver to check the fuel fill cap by showing a "CHECK FUEL CAP" message in the odometer/trip meter display (A), and it stores Temporary DTC P0457 "Evaporative Emission (EVAP) System Leak Detected/Fuel Cap Loose or Missing". Tightening the fuel cap does not make the message go off immediately.

Scheme 84

To make the message go off

Tighten the fuel fill cap properly, and do this procedure several times.

1. Turn the ignition switch OFF.
2. Start the engine, and drive at a steady speed over 28 mph (45 km/h), without moving the accelerator pedal, for about 1 minute.

Second drive cycle

During the second drive cycle after a cold start, if the fuel fill cap is still loose or missing, the ECM/PCM alerts the driver to check the fuel fill cap by showing a "CHECK FUEL CAP" message in the odometer/trip meter display as same as the first drive cycle. Tightening the fuel cap does not make the message go off immediately.

Third drive cycle

During the third drive cycle after a cold start, if the fuel fill cap is still loose or missing, the ECM/PCM stores DTC P0457 "Evaporative Emission (EVAP) System Leak Detected/Fuel Cap Loose or Missing". The malfunction indicator lamp (MIL) (A) comes on, and the "CHECK FUEL CAP" message goes off.

Scheme 85

Idle Control System Diagram

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

Scheme 86

1. After the engine starts, the IAC valve opens for a certain amount of time. The amount of air is increased to raise the idle speed.
2. When the engine coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. The amount of bypassed air is controlled in relation to engine coolant temperature.

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 engine.

Scheme 87

Intake Manifold Tuning (IMT) (Intake Manifold Runner Control (IMRC)) System (K20A3 engine)

Engine power is achieved by closing and opening the intake manifold tuning (IMT) (intake manifold runner control (IMRC)) valve. When the valve is closed, there is high torque at low engine speed. When the valve is open, there is high torque at high engine speed.

Scheme 88

Evaporative Emission (EVAP) Control Diagram-2002-2004 Models

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

Scheme 89

1. The EVAP canister is purged by drawing fresh air through it and into a port on the intake manifold. The purging vacuum is controlled by the EVAP canister purge valve, which operates whenever engine coolant temperature is above 149°F (65°C).
2. When vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and regulates the flow of fuel vapor to the EVAP canister.
3. During refueling, the fuel tank vapor control valve opens with the pressure in the fuel tank, and feeds the fuel vapor to the EVAP canister.

Evaporative Emission (EVAP) Control Diagram-2005-2006 Models

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

The EVAP canister is purged by drawing fresh air through it and into a port on the intake manifold.

The purging vacuum is controlled by the EVAP canister purge valve, which operates whenever engine coolant temperature is above 140°F (60°C).

Scheme 90

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Scheme 110

The vehicle has certain "readiness codes" that are part of the on-board diagnostics for the emissions systems. If the vehicle's battery has been disconnected or gone dead, if the DTCs have been cleared, or if the ECM/PCM has been reset, these readiness codes are reset. In some states, part of the emissions testing is to make sure these codes are set to complete. If all of them are not set to complete, the vehicle may fail the emission test, or the test cannot be finished.

To check if the readiness codes are set to complete, turn the ignition switch ON (II), but do not start the engine. The MIL will come on for 15-20 seconds. If it then goes off, the readiness codes are complete. If it flashes five times, one or more readiness codes are not set to complete. To set readiness codes from incomplete to complete, do the procedure for the appropriate code.

To check the status of a specific DTC system, check the OBD status in the DTC MENU with the HDS (see OBD STATUS (2005-2006 MODELS) ). This screen displays the code, the current data list of the enable criteria, and the status of the readiness testing.

Catalytic Converter Monitor and Readiness Code

Note. Do not turn the ignition switch off during the procedure. All readiness codes are cleared when the battery is disconnected or when the ECM/PCM is cleared with the HDS or a scan tool. Low ambient temperatures or excessive stop-and-go traffic may increase the drive time needed to switch the readiness code from incomplete to complete. The readiness code will not switch to complete until all the enable criteria are met. If a fault in the secondary HO2S system caused the MIL to come on, the readiness code cannot be set to complete until you correct the fault.

Enable Criteria

1. ECT at 158°F (70°C) or higher.
2. Intake air temperature (IAT) at 20°F (-7°C) or higher.
3. Vehicle speed sensor (VSS) reads more than 25 mph (40 km/h).

When the HDS is used (2002-2006 Models)

1. Connect the HDS to the vehicle's data link connector (DLC), and bring up the READINESS Codes screen for Catalyst in the DTCs MENU.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. After about 5 miles (8 km), the readiness code should switch to complete.
4. If the readiness code is still not set to complete, check for a Temporary DTC with the HDS. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

When a scan tool is used (2002-2004 Models)

1. Connect a scan tool to the vehicle's data link connector (DLC), and bring up the tool's generic OBD II mode.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. After about 5 miles (8 km), the readiness code should switch from incomplete to complete.
4. If the readiness code is still set to incomplete, check for a Temporary DTC. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

Evaporative Emission (EVAP) Control System Monitor and Readiness code

Note. All readiness codes are cleared when the battery is disconnected or when the ECM/PCM is cleared with the HDS or a scan tool (2002-2004 models). The enable criteria must be repeated if the intake air temperature (IAT) drops lower than 36°F (20°C) from its value at engine start up. At engine start up, ECT and IAT are higher than 32°F (0°C), but lower than 95°F (35°C). At engine start up, the ECT and IAT are within 12°F (7°C) of each other.

1. Battery voltage is higher than 10.5 V.
2. Engine at idle.
3. ECT sensor between 176°F (80°C) and 212°F (100°C).
4. MAP sensor less than 46.6 kPa (14 in.Hg, 350 mmHg).
5. Vehicle speed 0 mph (0 km/h).
6. IAT sensor between 32°F (0°C) and 212°F (100°C).

1. Connect the HDS to the vehicle's data link connector (DLC).
2. Start the engine.
3. Select EVAP TEST in the INSPECTION MENU with the HDS, then select the FUNCTION TEST in the EVAP TEST MENU. If the functions are normal, readiness is complete. If the functions are not normal, go to the next step.
4. If the readiness code is still not set to complete, check for a Temporary DTC. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

1. Connect a scan tool to the vehicle's data link connector (DLC), and bring up the tool's generic OBD II mode.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. After about 2.5 miles (4.0 km), the readiness code should switch from incomplete to complete.
4. If the readiness code is still set to incomplete, check for a Temporary DTC. If there is no DTC, one or more of the enable criteria were probably not met; repeat the procedure.

Air Fuel Ratio (A/F) Sensor Monitor and Readiness Code

Note. Do not turn the ignition switch off during the procedure. All readiness codes are cleared when the battery is disconnected or when the ECM/PCM is cleared with the HDS or a scan tool.

ECT at 140°F (60°C) or higher.

1. Start the engine.
2. Connect the HDS to the vehicle's data link connector (DLC).
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. During the drive, decelerate (with the throttle fully closed) for 5 seconds. After about 3.5 miles (5.6 km), the readiness code should switch from incomplete to complete.
4. Check the readiness codes screen for the Air Fuel Ratio (A/F) Sensor in the DTCs MENU with the HDS. If the screen shows complete, readiness is complete. If the screen shows not complete, go to the next step.
5. Check for a Temporary DTC. If there is no DTC, the enable criteria was probably not met. Select the DATA LIST Menu. Check the ECT in the ALL DATA LIST with the HDS. If the ECT is lower than 140°F (60°C), run the engine until it is higher than 140°F (60°C), then repeat the procedure.

1. Connect a scan tool to the vehicle's data link connector (DLC), and bring up the tool's generic OBD II mode.
2. Start the engine.
3. Test-drive the vehicle under stop-and-go conditions with short periods of steady cruise. During the drive, decelerate (with the throttle fully closed) for 5 seconds. After about 3.5 miles (5.6 km), the readiness code should switch from incomplete to complete.
4. If the readiness code is still set to incomplete, check for a Temporary DTC, If there is no DTC, the enable criteria was probably not met; repeat the procedure.

Air Fuel Ratio (A/F) Sensor Heater Monitor Readiness Code

Note. All readiness codes are cleared when the battery is disconnected or when the ECM/PCM is cleared with the HDS or a scan tool.

Procedure

1. Connect the HDS or a scan tool to the vehicle's data link connector (DLC). Bring up the tool's generic OBD II mode (scan tool only).
2. Start the engine, and let it idle for 1 minute. The readiness code should switch from incomplete to complete.
3. If the readiness code is still set to incomplete, check for a Temporary DTC. If there is no DTC, repeat the procedure.

Misfire Monitor and Readiness Code

1. This readiness code is always set to available because misfiring is continuously monitored.
2. Monitoring pauses, and the misfire counter resets, if the vehicle is driven over a rough road.
3. Monitoring also pauses, and the misfire counter holds at its current value, if the throttle position changes more than a predetermined value, or if driving conditions fall outside the range of any related enable criteria.

Fuel System Monitor and Readiness Code

1. This readiness code is always set to available because the fuel system is continuously monitored during closed loop operation.
2. Monitoring pauses when the catalytic converter, EVAP control system, and A/F sensor monitors are active.
3. Monitoring also pauses when any related enable criteria are not being met. Monitoring resumes when the enable criteria is again being met.

Comprehensive Component Monitor and Readiness Code

This readiness code is always set to available because the comprehensive component monitor is continuously running whenever the engine is cranking or running.

See also:
• MIL CIRCUIT TROUBLESHOOTING
• ECM/PCM IDLE LEARN PROCEDURE
• PASSENGER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION
• P0010 (56)
• P0116 (86)
• P0122 (7)
• P0123 (7)
• P0125 (86)
• P0128 (87)
• P0133 (61)
• P0134 (41)
• P0135 (41)
• P0139 (63)
• P0300 and some of P0301 (71) P0302 (72) P0303 (73) P0304 (74)
• P0325 (23)
• P0335 (4)
• P0341 (57)
• P0365 (8)
• P0420 (67)
• P0451 (91)
• P0452 (91)
• P0511 (HP)
• P0600 (39)
• P0607 (-)
• P0661 (107)
• P0700 (70)
• P1077 (106)
• P1078 (106)
• P1106 (13)
• P1121 (7)
• P1128 (5)
• P1129 (5)
• P1164 (61)
• P1167 (41)
• P1259 (22)
• P1456 (90)
• P1457 (90)
• P2279 (109)
• P2646 (22)
• P2647 (22)
• P0111 (10)
• P0128 (87)
• P0133 (61)
• P0171 (45)
• P0339 (4)
• P0344 (57)
• P0369 (8)
• P0443 (92)
• P0562 (34)
• P0602 (196)
• P0603 (131)
• P0606 (0)
• P0630 (139)
• P0685 (135)
• P0720 (122)
• P1009 (56)
• P1077 (106)
• P1109 (13)
• P1122 (7)
• P1172 (61)
• P1549 (34)
• P16BB (116)
• P2195 (48)
• P2227 (13)
• P2228 (13)
• P2229 (13)
• P2270 (63)
• P2610 (132)
• P2A00 (61)
• BATTERY TEST
• STARTER PERFORMANCE TEST
• FUEL PUMP CIRCUIT TROUBLESHOOTING
• FUEL PRESSURE TEST
• IDLE SPEED INSPECTION
• THROTTLE BODY TEST
• FUEL TANK VAPOR CONTROL VALVE TEST
• THROTTLE POSITION SENSOR SIGNAL INSPECTION
• HOW TO SET READINESS CODES
• ECM/PCM RESET (2005-2006 MODELS)
• OBD STATUS (2005-2006 MODELS)