Signal Sporadic. Permanent Fault

SIGNAL SPORADIC. PERMANENT FAULT





Checking Diagnostic Trouble Codes

- Ignition OFF.
- Check atmospheric pressure sensor connector (lilac) for contact resistance and oxidation and remedy.
- Check engine control module (ECM) connector for contact resistance and oxidation and remedy.
- Atmospheric pressure sensor connected.
- Engine control module (ECM) connected.
- START the engine and idle it.
- Wait 5 minutes.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

If reading is OK:
- The cause of the diagnostic trouble code (DTC) has been loose connections in the atmosphenc pressure sensor and/or engine control module (ECM) connectors.
- Then proceed to Verification section below..

If reading is incorrect:
- Proceed to test step below.





Checking Cables and Terminals

- Check atmospheric pressure sensor and/or engine control module (ECM) connector for loose connections.
- Check cable between atmospheric pressure sensor terminal and engine control module (ECM) #B29 for an intermittent open-circuit, intermittent short-circuit to ground and an intermittent short-circuit to supply voltage.
- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for an intermittent open-circuit, intermittent short-circuit to ground and an intermittent short-circuit to supply voltage.
- Check cable between atmospheric pressure sensor terminal 2 and engine control module (ECM) #B28 for an intermittent open-circuit.
- The atmospheric pressure sensor power cable is connected inside the engine control module (ECM) to the air conditioning (A/C) pressure sensor, fuel tank pressure sensor and accelerometer power cables. If anything happens to any of these cables all four will be affected.

- Check cables between:

- Air conditioning (A/C) pressure sensor terminal 3 and engine control module (ECM) #B29.
- Tank pressure sensor terminal 1 and engine control module (ECM) #B15.
- Accelerometer terminal 1 and engine control module (ECM) #B1 for intermittent short-circuit to supply voltage and an intermittent short circuit to ground.

- Reinstall all components.
- START the engine and idle it.
- Wait 5 minutes.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

Alternative Intermittent:
- Proceed to Verification section below.

Alternative Permanent:
- Proceed to test step below.





Checking the Air Conditioning Pressure Sensor

- Ignition OFF.
- Atmospheric pressure sensor connected.
- Disconnect air conditioning (A/C) pressure sensor.

Hint: Diagnostic trouble codes (DTCs) may be stored for the air conditioning (A/C) pressure sensor, erase codes when fault-tracing is completed.

- START the engine and idle it.
- Wait 5 minutes.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

Alternative Intermittent:
- Try a new air conditioning (A/C) pressure sensor.
- Proceed to Verification section below.

No:
- Proceed to test step below.





Checking Accelerometer

- Ignition OFF.
- Atmospheric pressure sensor connected.
- Connect air conditioning (A/C) pressure sensor.
- Disconnect accelerometer.

Hint: Diagnostic trouble codes (DTCs) may be stored for the accelerometer, erase codes when fault-tracing is completed.

- START the engine and idle it.
- Wait 5 minutes.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

Alternative Intermittent:
- Try a new accelerometer.
- Proceed to Verification section below.

Alternative Permanent:
- Proceed to test step below.





Checking Fuel Tank Pressure Sensor

- Ignition OFF.
- Atmospheric pressure sensor connected.
- Connect the accelerometer.
- Disconnect tank pressure sensor.

Hint: Diagnostic trouble codes (DTCs) may be stored for the fuel tank pressure sensor, erase codes when fault-tracing is completed.

- START the engine and idle it.
- Wait 5 minutes.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

Alternative Intermittent:
- Try a new tank pressure sensor.
- Then proceed to Verification section below.

Alternative Permanent:
- Try a new atmospheric pressure sensor.
- Then proceed to Verification section below.





Verification

- Hint: After carrying out the repair, check that the fault has been remedied as follows.

- Ignition OFF.
- Reconnect connectors and reinstall components.
- START the engine and idle it.
- Wait for a minute.
- Read off diagnostic trouble codes (DTCs).

If EFI-422 is stored it should have intermittent fault status.

Alternative Intermittent:
- Fault corrected.

Alternative Permanent:
- Proceed to test step below.

Fault-Tracing Information

- The verification result shows that the fault persists.
- Do you want to exit fault-tracing?

Yes:
- Fault not corrected.

No:
- Return to Checking Diagnostic Trouble Codes section above.