Fuel and Emissions Systems: Other Acura RDX I facelift

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 terminals 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.

Service Information

Some DTCs or symptoms can be caused by a combination of PCM software and specific driving habits. Periodically, new PCM software or new service procedures may become available. Always check online for the latest software or service information related to the DTCs or symptoms you are troubleshooting.

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 terms, this usually means something won't work at all. With complex electronics (such as PCMs) this can sometimes mean something works, but not the way it's supposed to.

HDS Clear Command

The PCM stores various specific data to correct the system even if there is no electrical power, such as when the battery negative terminal or the No. 19 Fl MAIN (15 A) fuse is 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, PCM reset, and CKP pattern clear. The DTC clear command erases all stored DTC codes, freeze data, on-board snapshot, and readiness codes. This must be done with the HDS after reproducing the DTC during troubleshooting.

The PCM reset command erases all stored DTCs, freeze data, on-board snapshot, readiness codes, and all specific data to correct the system except CKP pattern. If the CKP pattern data in the 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.

Learn Procedure (without the HDS)

1. Start the engine. Hold the engine speed at 3, 000 RPM without load (in P or N) until the radiator fan comes on.
2. Test-drive the vehicle on a level road: Decelerate (with the throttle fully closed) from an engine speed of 2, 500 RPM down to 1, 000 RPM with the transmission in S position 1st or 2nd gear.
3. Repeat step 2 several times.
4. Turn the ignition switch to LOCK (0).
5. Turn the ignition switch to ON (II), and wait 30 seconds.

Substituting the PCM

Special Tools Required

1. Honda Diagnostic System (HDS) tablet tester
2. Honda Interface Module (HIM) and an iN workstation with the latest HDS software version
3. HDS pocket tester
4. GNA600 and an iN workstation with the latest HDS software version
5. MVCI unit with the latest control module (CM) update software installed

Any one of the above updating tools can be used.

Note. Use this procedure when you have to substitute a known-good PCM during the troubleshooting procedures. Make sure the HDS/iN workstation or the MVCI has the latest HDS software version.

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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. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the PCM and other vehicle systems. If it does not, go to the DLC circuit troubleshooting (see «DLC CIRCUIT TROUBLESHOOTING»(ref-513833-S41457160082012111600000) ).
4. Turn the ignition switch to LOCK (0).
5. Jump the SCS line with the HDS.
6. Disconnect PCM connectors A, B, and C. NOTE: PCM connectors A, B, and C have symbols (A=[], B=delta, C=o) embossed on them for identification.
7. Remove the bolts (D), then remove the PCM assembly (E).
8. Remove the cover (A) and the bracket (B) from the PCM (C).
9. Install a known-good PCM in the reverse order of removal.
10. Turn the ignition switch to ON (II). NOTE: DTC P0630 (VIN Not Programmed or Mismatch) may be stored because the VIN has not been programmed into the PCM; ignore it, and continue this procedure.
11. Manually input the VIN to the PCM with the HDS.
12. Select the IMMOBI system with the HDS.
13. Enter the immobilizer PCM code that you got from the iN, and use the PCM replacement procedure in the IMMOBI Menu of the HDS; it allows you to start the engine.
14. Select the PGM-FI system, and reset the PCM with the HDS.
15. Update the PCM if it does not have the latest software (see «PCM UPDATE»(ref-513833-S16680197442012111600000) ).
16. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(ref-513856-S30291526352012111600000) ).
17. Do the CKP pattern clear/CKP pattern learn procedure.

OBD Status

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

1. PASSED: The on board diagnosis is successfully finished.
2. FAILED: The 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 for the DTC.

Electronic Control System

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

Fail-safe Function

When an abnormality occurs in the signal from a sensor or from another control unit, the PCM ignores that signal and substitutes a pre-programmed value for them that allows the engine to continue running. This causes a Confirmed DTC to be stored and the MIL to come on.

MIL Bulb Check and Readiness Code Condition

When the ignition switch is turned to ON (II), the PCM turns on the MIL via the F-CAN 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 off.

Self Shut Down (SSD) Mode

After the ignition switch is turned to LOCK (0), the PCM stays on (about 30 minutes). If the PCM connector is disconnected during this time, the 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 to LOCK (0).

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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 PCM receives a demand for cooling from the A/C system, it delays the compressor from being energized, and enriches the mixture to assure a smooth transition to the A/C mode.

Air Fuel Ratio (A/F) Sensor

The A/F sensor operates over a wide mixture range. The A/F sensor is installed upstream of the warm up three way catalytic converter (WU-TWC), and it sends signals to the PCM which varies the duration of fuel injection accordingly.

Scheme 47

Barometric Pressure (BARO) Sensor

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

Camshaft Position (CMP) Sensor B

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

Scheme 48

Crankshaft Position (CKP) Sensor

The CKP sensor detects crankshaft speed and is used by the PCM to determine ignition timing, timing for fuel injection of each cylinder, and engine misfire detection.

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Engine Coolant Temperature (ECT) Sensors 1 and 2

ECT sensors 1 and 2 are temperature dependent resistors (thermistors). The resistance decreases as the engine coolant temperature increases.

ECT sensor 1 is on the cylinder head, and ECT sensor 2 is on the radiator.

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Ignition Timing Control

The 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 and intake air temperature.

Injector Timing and Duration

The 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 short term fuel trim (ST FUEL TRIM), the PCM detects long term malfunctions in the fuel system and sets a diagnostic trouble code (DTC) if needed.

Intake Air Temperature (IAT) Sensor 2

IAT sensor 2 is a temperature dependent resistor (thermistor). The resistance of the thermistor decreases as the intake air temperature increases.

Scheme 52

Knock Sensor

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

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Manifold Absolute Pressure (MAP) Sensor

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

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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 DTCs have been cleared, or if the PCM has been reset, these 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 test, or the test cannot be finished.

To check if the readiness codes are set to complete, turn the ignition switch to 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.

Mass Air Flow (MAF) Sensor/Intake Air Temperature (IAT) Sensor 1

MAF sensor/IAT sensor 1 contains a hotwire, a cold film, and a thermistor. It is located in the intake air passage. The resistance of the hot wire, the cold film, and the thermistor changes due to intake air flow and air temperature. The control circuit in the MAF sensor controls the current to keep the hot wire at a set temperature. The current is converted to voltage in the control circuit, then output to the PCM.

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Output Shaft (Countershaft) Speed Sensor

This sensor detects output shaft (countershaft) speed.

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Secondary Heated Oxygen Sensor (Secondary HO2S)

The secondary HO2S detects the oxygen content in the exhaust gas downstream of the warm up three way catalytic converter (WU-TWC), and sends signals to the PCM which varies the duration of fuel injection accordingly. To stabilize its output, the sensor has an internal heater. The PCM compares the HO2S output with the A/F sensor output to determine catalyst efficiency. The secondary HO2S is located on the WU-TWC.

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Starter Control System Diagram

The starter control system controls the starter motor.

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1. When the ignition switch is turned to START (III), the PCM applies current to starter cut relay 1 (STR) and starter cut relay 2 (ST CUT), then battery voltage is applied to the starter motor to run.
2. Once the ignition switch is released, the PCM keeps the starter motor running until the engine starts. If the PCM detects that the engine starts, the PCM stops applying current to the relays, then the starter motor stops.
3. If you turn the ignition switch to START (III) while the engine is running, the starter motor does not run.
4. In the following cases, the PCM stops the starter motor; To prevent the starter motor from overheating, when the engine does not start within 10 seconds. To protect the starter motor if the engine RPM is too high when the starter motor is running.
5. If a malfunction occurs with the starter system, the starter system indicator comes on, and starter control is disabled. The engine can still be started using the ignition switch.

Electronic Throttle Control System

The throttle is electronically controlled. Refer to the system diagram to see a functional layout of the system.

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

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

Cruise control: The PCM controls the throttle actuator to maintain set speed when the cruise control is operating. The throttle actuator takes the place of the cruise control actuator.

Accelerator Pedal Position (APP) Sensor

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

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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.

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Electronic Throttle Control System Diagram

The electronic throttle control system consists of the throttle actuator, throttle position (TP) sensor A/B, accelerator pedal position (APP) sensor A/B, the electronic throttle control system (ETCS) control relay, and the PCM.

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1. The i-VTEC has a variable valve timing control (VTC) 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.

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1. The VTC system makes continuous intake valve timing changes based on operating conditions.
2. Intake valve timing is optimized to allow the engine to produce maximum power.
3. Cam angle is advanced to obtain EGR effect and reduce 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. The system reduces the cam advance at idle, stabilizes combustion, and reduces engine speed.
5. If a malfunction occurs, the VTC system control is disabled and the valve timing is fixed at the fully retarded position.

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1. The VTEC system changes the one side of the intake side cam profile to correspond to the engine speed. It maximizes torque at low engine speed and output at high engine speed.
2. The low lift cam is used by one side of the intake valves at a low engine speed. At high engine speed, both intake valves uses the high lift cam.

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Camshaft Position (CMP) Sensor A

CMP sensor A detects camshaft angle position for the VTC system.

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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 PCM controls current to the throttle actuator to maintain the correct idle speed.

Brake Pedal Position Switch

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

Power Steering Pressure (PSP) Switch

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

Fuel Cutoff Control

During deceleration with the throttle valve closed, current to the injectors is cut off to improve fuel economy at engine speeds over 850 RPM. Fuel cutoff control also occurs when the engine speed exceeds 6, 900 RPM, 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 5, 000 RPM. Engine speed of fuel cut is lower on a cold engine.

Fuel Pump Control

When the ignition switch is turned to ON (II), the PCM grounds PGM-FI main relay 2 which feeds current to the fuel pump control module. The PCM sends a signal to the fuel pump control module to operate the fuel pump for 2 seconds to pressurize the fuel system. When the engine starts, the fuel pump speed is controlled in four levels by the fuel pump control module. The PCM selects the fuel pump speed based on calculating the injector activation time and the engine speed, and then sends an operation command signal to the fuel pump control module. This operation decreases fuel pump noise at low engine speed.

PGM-FI Main Relay 1 and 2

PGM-FI main relay 1 is energized whenever the ignition switch is ON (II) to supply battery voltage to the PCM, 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 (fuel pump control module) for 2 seconds when the ignition switch is turned to ON (II), and when the engine is cranking or running.

Transfer Fuel Pump

The fuel in the right side of the fuel tank is drawn over to the left side by the transfer fuel pump.

Turbocharger Control System

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

Turbocharger Boost Sensor

This sensor converts charge air cooler pressure into an electrical signal that is received by the PCM.

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Turbocharger Wastegate Control Solenoid Valve

This solenoid valve controls pressure to the turbocharger wastegate control actuator. The solenoid itself is controlled by the PCM. The following information describes the ports on the valve and where the pressure flows when the solenoid switches the valve on and off.

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1. Port A-To the intake air duct (turbocharger inlet connecting tube)
2. Port B-To the turbocharger wastegate control actuator
3. Port C-To the intake air duct (turbocharger outlet pipe)

Turbocharger Bypass Control Solenoid Valve

This solenoid valve controls pressure to the turbocharger bypass control valve. The solenoid itself is controlled by the PCM. The following information describes the ports on the valve and where the pressure flows when the solenoid switches the valve on and off.

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1. Port A-To the charge air cooler
2. Port B-To the turbocharger bypass control valve
3. Port C-To the intake manifold

Turbocharger Boost Control Solenoid Valve

This solenoid valve controls pressure to the turbocharger boost control valve. The solenoid itself is controlled by the PCM. The following information describes the ports on the valve and where the pressure flows when the solenoid switches the valve on and off.

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1. Port A-To the intake air duct (turbocharger inlet connecting tube)
2. Port B-To the turbocharger boost control actuator
3. Port C-To the intake air duct (turbocharger outlet pipe)

Turbocharger Control System Diagram

The turbocharger control system controls the boost pressure and the response of the turbocharger. The PCM controls the turbocharger wastegate control solenoid valve (duty controlled), the turbocharger bypass control solenoid valve (on/off controlled), and the turbocharger boost control valve (duty controlled). The boost pressure is monitored by the turbocharger boost sensor.

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Turbocharger Wastegate Control System

This system controls the wastegate control solenoid to prevent the turbo from exceeding maximum boost pressure. This system is duty controlled by the PCM. The descriptions A and B are the two conditions of duty. Condition A (maximum duty) and condition B (minimum duty). At other times, the turbocharger wastegate control solenoid controls both the passages from the intake air duct (turbocharger inlet connecting tube), and the intake air duct (turbocharger outlet pipe) to the turbocharger wastegate control actuator.

Condition A (maximum duty)

When the turbocharger boost sensor signal is lower than the upper limit, the PCM turns on (maximum duty) the turbocharger wastegate control solenoid valve, and opens the passage between the intake air duct (turbocharger inlet connecting tube) and the turbocharger wastegate control actuator and closes the passage from the intake air duct (turbocharger outlet pipe) and the turbocharger wastegate control actuator. The pressure at the turbocharger wastegate control actuator is released to the intake air duct (turbocharger inlet connecting tube), and the spring in the turbocharger wastegate control actuator closes the turbocharger wastegate control valve. In this condition, all of the exhaust gas flows to the turbine. This increases the RPM of the turbine, increasing boost pressure.

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Condition B (minimum duty)

When the turbocharger boost sensor signal reaches the upper limit, the PCM turns off (minimum duty) the turbocharger wastegate control solenoid valve, and opens the passage between the intake air duct (turbocharger outlet pipe) and the turbocharger wastegate control actuator and closes the passage from the intake air duct (turbocharger inlet connecting tube) and the turbocharger wastegate control actuator. The boost pressure from the intake air duct (turbocharger outlet pipe) pushes the turbocharger wastegate control actuator and opens the turbocharger wastegate control valve. In this condition, only a portion of the exhaust gas flows through the bypass passage bypassing the turbocharger wastegate control valve, and the amount of exhaust gas to the turbocharger decreases. This decreases the RPM of the turbine decreasing boost pressure.

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Turbocharger Bypass Control System

This system improves the boost response of acceleration immediately after deceleration. This system also protects the turbocharger from the negative effects of compressor surge during high boost. The descriptions A and B are the two conditions of the turbocharger bypass control solenoid valve on and off. Condition A (on) and condition B (off).

Condition A (Solenoid Valve ON)

When the vehicle is in cruise or accelerating, the PCM turns on the turbocharger bypass control solenoid valve, and opens the passage between the charge air cooler and the turbocharger bypass control valve and closes the passage between the intake manifold and the turbocharger bypass control valve. The boost pressure from the charge air cooler pushes the turbocharger bypass control valve, and closes the passage between the charge air cooler and the intake air duct (turbocharger inlet pipe). By doing this, all compressed air is routed to the intake manifold.

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Condition B (Solenoid Valve OFF)

During the deceleration with the throttle valve closed, the PCM turns off the turbocharger bypass control solenoid valve and opens the passage between the intake manifold and the turbocharger bypass control valve and closes the passage between the charge air cooler and the turbocharger bypass control valve. The vacuum pressure from the intake manifold pulls the turbocharger bypass control valve and opens the passage between the charge air cooler and the intake air duct (turbocharger inlet pipe). By doing this, the compressed air flows from the charge air cooler to the intake air duct (turbocharger inlet pipe) to keep the turbine spinning. This improves the acceleration response of the turbocharger after deceleration.

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Turbocharger Boost Control System

This system controls the exhaust gas passage to the turbine by changing the variable flap angle. The variable flap is moved by the turbocharger boost control actuator, and it is duty controlled by the PCM depending on the driving condition.

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When the variable flap is fully closed, all exhaust gas flows to the inner scroll of the turbocharger. Under this condition, the exhaust gas speed is accelerated, and the turbocharger response is improved. When the variable flap is fully opened, the exhaust gas flows through both the outer and the inner scroll of the turbocharger. Under this condition, the exhaust gas is efficiently used to improve the maximum boost. Because of this system, the turbocharger functions both as a quick responding small size turbocharger, and high capacity turbocharger.

The description A and B are the two conditions of duty. Condition A (maximum duty) and condition B (minimum duty). At other times, the turbocharger boost controls both the passages from the intake air duct (turbocharger inlet connecting tube), and the intake air duct (turbocharger outlet pipe) to the turbocharger boost control actuator.

Under a low engine speed/low load condition (with only a small amount of exhaust gas), the PCM turns on (maximum duty) the turbocharger boost control solenoid valve and opens the passage between the intake air duct (turbocharger inlet connecting tube) and the turbocharger boost control actuator and closes the passage between the intake air duct (turbocharger outlet pipe) and the turbocharger boost control actuator. The pressure at the turbocharger boost control actuator is released to the intake air duct (turbocharger inlet connecting tube), and the spring inside the turbocharger boost control actuator closes the variable flap. With the variable flap closed, the exhaust gas flows at high speed through the inner scroll of the turbocharger improving the turbo response.

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Under a medium or high load conditions (with large amount of exhaust gas), the PCM turns off (minimum duty) the turbocharger boost control solenoid valve and opens the passage between the intake air duct (turbocharger outlet pipe) and the turbocharger boost control actuator and closes the passage between the intake air duct (turbocharger inlet connecting tube) and the turbocharger boost control actuator. The boost pressure from intake air duct (turbocharger outlet pipe) pushes the turbocharger boost control actuator which opens the variable flap. With the variable flap opened, the exhaust gas flows through both the inner and the outer scroll for efficient turbo operation at medium and high engine speed.

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Warm Up Three Way Catalytic Converter (WU-TWC) and Three Way Catalytic Converter (TWC)

The WU-TWC/TWC converts hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (C02), nitrogen (N2), and water vapor.

WU-TWC (ATTACHED TO THE TURBOCHARGER)

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TWC (UNDER THE FLOOR)

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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. The PCV valve opens at idle, low load, and decelerating with the throttle valve fully closed.

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Evaporative Emission (EVAP) Control System

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

EVAP Canister Purge Valve

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

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Fuel Tank Pressure (FTP) Sensor

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

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EVAP Canister Vent Shut Valve

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

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

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Evaporative Emissions (EVAP) Control System Diagram

The EVAP control system minimizes the 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 purge amount and timing is duty controlled by the PCM by operating the EVAP canister purge valve. This system is operated whenever the engine coolant temperature is above 140°F(60°C). For this turbo engine model, there are two different purge flow passages, because the intake manifold pressure can be positive (boost pressure) or negative (vacuum pressure).

Purge to the throttle body

When the engine is under a low load condition, the pressure inside the intake manifold is negative (vacuum pressure). The vacuum pressure of the intake manifold opens non-return valve A and closes non-return valve B. Under this condition, the purge air flows from the EVAP canister through the EVAP canister purge valve and non-return valve A, into the throttle body.

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Purge to the intake air duct (turbocharger inlet pipe)

When the engine load increases, the pressure after the turbocharger changes to positive pressure due to turbocharger operation. The boost pressure at the throttle body closes non-return valve A, and due to the boost pressure at the charge air cooler, some part of the compressed air flows through the passage from the air bypass valve base to the intake air duct (turbocharger inlet pipe). When the speed of that compressed air increases at the EVAP canister purge nozzle, it draws the purge air from the EVAP canister side. The non-return valve B opens by this vacuum pressure, and the purge air flows from the EVAP canister through the EVAP canister purge valve and non-return valve B, into the intake air duct (turbocharger inlet pipe).

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Purge to the both intake air duct (turbocharger inlet pipe) and the throttle body

When the engine is under a medium load condition, the pressure after the turbocharger is positive due to the turbocharger operation, but the pressure at the intake manifold is negative because the throttle valve is nearly closed. Under this condition, both non-return valves A and B open and the purge air flows from the EVAP canister through the EVAP canister purge valve and non-return valves A and B, into the throttle body and the intake air duct (turbocharger inlet pipe).

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Fuel Cap Warning Message

The PCM detects a loose or missing fuel fill cap as an evaporative system leak and alerts the driver by showing a warning message in the multi-information display (MID).

First drive cycle

The first time a leak is detected a TIGHTEN FUEL CAP message in the MID (A). To scroll to another message, press the select/reset button. The TIGHTEN FUEL CAP message appears each time you restart the engine until the system turns the message off. Turn the engine off then replace or tighten the fuel fill cap until it clicks at least once.

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Procedure

1. Tighten the fuel fill cap until it clicks.
2. Clear the Pending DTC with the HDS.
3. Verify there is no leak by doing the EVAP FUNCTION TEST in the INSPECTION MENU with the HDS.

1. Tighten the fuel fill cap until it clicks.
2. Start the engine, then turn the ignition switch to LOCK (0).
3. Repeat step 2 two more times.

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 DTCs have been cleared, or if the PCM has been reset, these readiness codes are reset to incomplete. 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 to ON (II), but do not start the engine. The MIL comes on for 15-20 seconds. If it then goes off, the readiness codes are set to 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 ). This screen displays the DTC, 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 to ACC (I) or to LOCK (0) during the procedure. All readiness codes are cleared when the battery is disconnected, if DTCs have been cleared, or if the PCM is reset with the HDS. 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 ail 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 SENSOR 1 at 158°F (70°C) or more.
2. IAT SENSOR 1 at 20°F (-7°C) or more.
3. Vehicle speed above 25 mph (40 km/h).

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 Pending DTC with the HDS. 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, if DTCs have been cleared, or if the PCM is reset with the HDS.

1. Battery voltage is more than 10.5 V.
2. Engine at idle.
3. ECT SENSOR 1 and 2 between 176°F (80°C) and 212°F (100°C).
4. Vehicle speed 0 mph (0 km/h).
5. IAT SENSOR 1 between 32°F (0°C) and 212°F (100°C).

1. Connect the HDS to the DLC.
2. Start the engine.
3. Select the EVAP TEST in the INSPECTION MENU with the HDS, then select the FUNCTION TEST in the EVAP TEST MENU. If the result is normal, readiness is complete. If the result is not normal, go to the next step.
4. Check for a Pending 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 to ACC (I) or to LOCK (0) during the procedure. All readiness codes are cleared when the battery is disconnected, if DTCs have been cleared, or if the PCM is reset with the HDS.

ECT SENSOR 1 at 140°F (60°C) or more.

1. Start the engine.
2. 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.
3. Check the readiness codes screen for the AIR FUEL RATIO (A/F) SENSOR in the DTCs MENU with the HDS. If the HDS indicates complete, readiness is complete. If the HDS indicates not complete, go to the next step.
4. Check for a Pending DTC. If there is no DTC, the enable criteria was probably not met. Select the DATA LIST MENU. Check the ECT SENSOR 1 in the ALL DATA LIST with the HDS. If ECT SENSOR 1 is less than 140°F (60°C), run the engine until it is more than 140°F (60°C), then repeat the procedure.

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

Note. All readiness codes are cleared when the battery is disconnected, if DTCs have been cleared, or if the PCM is reset with the HDS.

1. Start the engine, and let it idle for 1 minute. The readiness code should switch from incomplete to complete.
2. If the readiness code is still not set to complete, check for a Pending 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.