Toyota Avalon (XX50): Fuel Rail / System Pressure - Too High (P008800). Mass or Volume Air Flow Sensor "A" Circuit Short to Battery (P010012,P010014). Mass or Volume Air Flow Sensor "A" Signal Plausibility Failure (P010064

Fuel Rail / System Pressure - Too High (P008800)

DESCRIPTION

Refer to DTC P008700.

Click here

MONITOR DESCRIPTION

If the fuel pressure increases despite a decrease request signal being sent to the fuel pump assembly (for high pressure side) by the ECM, the ECM will illuminate the MIL and store this DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

HINT:

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

• Permanent misfire and fuel system DTCs can only be cleared when performing the universal trip driving pattern when no malfunction is detected.

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Record the Freeze Frame Data.
5. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
6. Turn the engine switch off and wait for at least 30 seconds.
7. Start the engine.
8. Turn the Techstream on.
9. Based on the engine speed, engine load and other conditions displayed in the freeze frame data, reproduce the conditions present when the DTC was stored.
10. Enter the following menus: Powertrain / Engine / Trouble Codes.
11. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
12. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
13. Input the DTC: P008800.
14. Check the DTC judgment result.

    Techstream Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system has a malfunction.

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG) and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Trouble Codes.

(d) Read the DTCs.

HINT:

If any DTCs other than P008800 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

(a) Connect the Techstream to the DLC3.

(b) Start the engine and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine / Data List / Fuel Pressure (High).

(d) According to the display on the Techstream, read the Data List while racing the engine.

OK:

Fuel pressure fluctuates.

HINT:

Perform "Inspection After Repair" after replacing the fuel pressure sensor (for high pressure side).

Click here

NG

REPLACE FUEL DELIVERY PIPE WITH SENSOR ASSEMBLY LH (FUEL PRESSURE SENSOR (FOR HIGH PRESSURE SIDE))

OK

(a) Replace the fuel pump assembly (for high pressure side).

Click here

HINT:

Perform "Inspection After Repair" after replacing the fuel pump assembly (for high pressure side).

Click here

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTC.

(e) Turn the engine switch off and wait for at least 30 seconds.

NEXT

(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(b) Enter the following menus: Powertrain / Engine / Trouble Codes.

(c) Read the DTCs.

A

END

B

REPLACE ECM

Mass or Volume Air Flow Sensor "A" Circuit Short to Battery (P010012,P010014)

DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the intake air volume using the following built-in components:

• By-pass duct (allows some of the intake air to flow past a silicon chip sensor)
• Silicon chip sensor (uses a heater control bridge circuit and temperature sensor bridge circuit to detect the difference in the temperature of the intake air that passes the sensors positioned before and after the heater).
• Control circuit (converts the difference in temperature into a pulse signal and performs correction)

Intake air flows past the temperature sensor (before heater), the heater, and then the temperature sensor (after heater) of the silicon chip sensor in the by-pass duct. As the intake air is warmed up when it is exposed to the heater, the temperature of the intake air as it flows past the temperature sensor (after heater) is higher than when it flows past the temperature sensor (before heater). The difference in temperature of the intake air at each temperature sensor varies depending on the velocity of the intake air that flows past the silicon chip sensor. The temperature sensor bridge circuit detects the difference in temperature and the control circuit converts it into a pulse signal and outputs it to the ECM. When the temperature detected by the temperature sensor (before heater) is higher than that detected by the temperature sensor (after heater), backflow of the intake air is detected.

The ECM calculates the intake air volume based on the pulse signal received from the mass air flow meter sub-assembly, and uses it to determine the fuel injection duration necessary for an optimal air-fuel ratio.

The heater control bridge circuit has a temperature sensor and power transistor, and maintains the heater temperature at a specific temperature.

HINT:

When DTCs is stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM calculates the fuel injection duration based on the engine speed and throttle valve angle. Fail-safe mode continues until a pass condition is detected.

MONITOR DESCRIPTION

If there is a defect or an open or short circuit in the mass air flow meter sub-assembly, the frequency level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the mass air flow meter sub-assembly circuit and stores a DTC.

Example:

When the sensor output frequency remains less than 0.1 kHz, or higher than 9.8 kHz for 3 seconds, the ECM stores a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

HINT:

• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  Click here

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
5. Turn the engine switch off and wait for at least 30 seconds.
6. Turn the engine switch on (IG).
7. Turn the Techstream on.
8. Wait 3 seconds or more [A].
9. Enter the following menus: Powertrain / Engine / Trouble Codes [B].
10. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
12. Input the DTC: P010012 or P010014.
13. Check the DTC judgment result.

    Techstream Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system has a malfunction.
    • If the judgment result is INCOMPLETE, perform steps [A] through [B] again.
    • [A] to [B]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

(a) Disconnect the mass air flow meter sub-assembly connector.

(b) Turn the engine switch on (IG).

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

NG

GO TO STEP 5

OK

(a) Replace the mass air flow meter sub-assembly.

Click here

HINT:

Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

Click here

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTC.

(e) Turn the engine switch off and wait for at least 30 seconds.

NEXT

(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(b) Enter the following menus: Powertrain / Engine / Trouble Codes.

(c) Read the DTCs.

A

END

B

REPLACE ECM

(a) Disconnect the mass air flow meter sub-assembly connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

OK

REPLACE ECM

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

Mass or Volume Air Flow Sensor "A" Signal Plausibility Failure (P010064)

DESCRIPTION

Refer to DTC P010012.

Click here

MONITOR DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine fuel injection timing and to provide an appropriate air fuel ratio. Inside the mass air flow meter sub-assembly, there is a heated platinum wire which is exposed to the flow of intake air. By applying a specific electrical current to the wire, the ECM heats it to a specific temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to the mass air flow meter sub-assembly. The voltage level is proportional to the airflow through the sensor, and the ECM uses it to calculate the intake air volume.

The ECM monitors the average engine load value ratio to check the mass air flow meter sub-assembly for malfunctions. The average engine load value ratio is obtained by comparing the average engine load calculated from the mass air flow meter sub-assembly output to the average engine load estimated from the driving conditions, such as the engine speed and the throttle opening angle. If the average engine load value ratio is below the threshold value, the ECM determines that the intake air volume is low, and if the average engine load value ratio is above the threshold value, the ECM determines that the intake air volume is high.

If this is detected in 2 consecutive driving cycles, the MIL is illuminated and the DTC is stored.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

HINT:

• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  Click here

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
5. Turn the engine switch off and wait for at least 30 seconds.
6. Turn the engine switch on (IG).
7. Turn the Techstream on.
8. Start the engine and warm it up until the engine coolant temperature is 70°C (158°F) or higher [A].
9. Drive the vehicle at approximately 80 km/h (50 mph) to 112 km/h (70 mph) for 5 minutes or more [B].

   CAUTION:

   When performing the confirmation driving pattern, obey all speed limits and traffic laws.

   HINT:

   Drive while keeping the engine load as stable as possible.

10. Enter the following menus: Powertrain / Engine / Trouble Codes [C].
11. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
12. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
13. Input the DTC: P010064.
14. Check the DTC judgment result.

    Techstream Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system is malfunctioning.
    • If the judgment result is INCOMPLETE, perform steps [B] through [C] again.
    • [A] to [C]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

Refer to DTC P010012.

Click here

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

HINT:

If any DTCs other than P010064 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

(a) Check the intake system for vacuum leaks.

Click here

OK:

No leaks from the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system.

Click here

NG

REPAIR OR REPLACE INTAKE SYSTEM

OK

(a) Check the PCV hose connections.

Click here

OK:

PCV valve and hose are connected correctly and are not damaged.

NG

REPAIR OR REPLACE PCV HOSE

OK

(a) Replace the mass air flow meter sub-assembly.

Click here

HINT:

Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

Click here

NEXT

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTC.

(e) Turn the engine switch off and wait for at least 30 seconds.

NEXT

(a) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(b) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

(c) Input the DTC: P010064.

(d) Check the DTC judgment result.

NEXT

END