Signal Too High. Permanent Fault

SIGNAL TOO HIGH. PERMANENT FAULT





Checking Ground Lead

- Ignition OFF.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect atmospheric pressure sensor (lilac connector).
- Connect an ohmmeter between atmospheric pressure sensor connector 2 and ground.

The ohmmeter should read approx. 0 Ohms.

If reading is OK:
- Proceed to Checking Signal Cable section below.

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





Checking Engine Control Module Connector

- Ignition OFF.
- Atmospheric pressure sensor disconnected.
- Check engine control module (ECM) connector for contact resistance and oxidation and remedy.
- Engine control module (ECM) connected.
- Connect an ohmmeter between atmospheric pressure sensor connector 2 and ground.

The ohmmeter should read approx. 0 Ohms.

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

If reading is incorrect:
- Check cable between atmospheric pressure sensor terminal 2 and engine control module (ECM) #B28 for an open-circuit.
- Then proceed to Verification section below.





Checking Signal Cable

- Ignition ON.
- Atmospheric pressure sensor disconnected.
- Connect a test light (3 W bulb at least) between atmospheric pressure sensor connector terminal 2 and ground.

The bulb should not light.

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

If reading is incorrect:
- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for a short-circuit to supply voltage.
- Then proceed to Verification section below.





Checking Signal Cable Resistance

- Ignition OFF.
- Atmospheric pressure sensor disconnected.
- Connect an ohmmeter between atmospheric pressure sensor connector 3 and ground.

The ohmmeter should read less than approx. 10K Ohms.

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

If reading is incorrect:
- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for an open-circuit.
- Then proceed to Verification section below.





Checking Power Cable

- Ignition ON.
- Atmospheric pressure sensor disconnected.
- Connect a voltmeter between atmospheric pressure sensor connector terminal 1 and ground.

The voltmeter should read approx. 5 Volts.

If reading is OK:
- Try a new atmospheric pressure sensor.
- Then proceed to Verification section below.

If readin9 is incorrect:
- Proceed to test step below.





Checking Cables:

- Ignition OFF.
- Disconnect air conditioning (A/C) pressure sensor, fuel tank pressure sensor and accelerometer.
- Atmospheric pressure sensor disconnected.
- Ignition ON.
- Connect a voltmeter between atmospheric pressure sensor connector terminal 1 and ground.

The voltmeter should read approx. 5 Volts.

If reading is OK:
- Proceed to Checking Fuel Tank Pressure Sensor section below.

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





Checking for a Short-Circuit

The atmospheric pressure sensor power cable is connected inside the engine control module (ECM) to the air conditioning (AC) pressure sensor, fuel tank pressure sensor and accelerometer power cables. If anything happens to any of these cables all four will be affected.

Check wiring between:

- 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.
- atmospheric pressure sensor terminal 1 and engine control module (ECM) #B29.

For a short-circuit to supply voltage.

- Then proceed to Verification section below.





Checking Fuel Tank Pressure Sensor

- Ignition OFF.
- Connect fuel tank pressure sensor.
- Atmospheric pressure sensor, air conditioning (A/C) pressure sensor and accelerometer disconnected.
- Ignition ON.
- Connect a voltmeter between atmospheric pressure sensor terminal 1 and ground.

The voltmeter should read approx. 5 Volts.

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

If reading is Incorrect:
- Try a new tank pressure sensor.
- Then proceed to Verification section below.





Checking the A/C Pressure Sensor

- Ignition OFF.
- Connect air conditioning (A/C) pressure sensor.
- Atmospheric pressure sensor and accelerometer disconnected.
- Ignition ON.
- Connect a voltmeter between atmospheric pressure sensor terminal 1 and ground.

The voltmeter should read approx. 5 Volts.

If reading is OK:
- Try a new accelerometer.
- Then proceed to Verification section below.

If reading is incorrect:
- Try a new air conditioning (A/C) 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 veritication result shows that the fault persists.
- Do you want to exit tault-tracing?

Yes:
- Fault not corrected

No:
- Return to Checking Ground Lead section above.