Signal Missing. Permanent Fault

Checking Engine Speed Sensor Resistance
- Ignition off.
- Disconnect the engine speed (RPM) sensor.
- Connect a voltmeter between engine speed sensor connector terminal 1 and 2 (engine control module (ECM) side).
- The ohmmeter should read approx. 200 - 500 ohms depending on engine speed sensor temperature.

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

If reading is incorrect:
^ Try a new engine speed sensor.
^ Then proceed to Verification section below.





Checking Ground Lead
- Ignition off.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Engine speed sensor disconnected.
- Connect an ohmmeter between engine speed sensor connector terminal 2 (engine control module side) and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ Proceed to Checking Signal Cable Resistance To Ground section below.

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





Checking Engine Control Module Ground Terminals
- Ignition off.
- Engine speed sensor disconnected.
- Check engine control module connector and ground terminals 31/32 and 31/33 for contact resistance and oxidation and remedy.
- Engine control module connected.
- Connect an ohmmeter between engine speed sensor connector terminal 2 (engine control module side) 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 engine speed sensor connector 2 and engine control module # A6 for an open-circuit.
^ Then proceed to Verification section below.





Checking Signal Cable Resistance To Ground
- Ignition off.
- Engine speed sensor disconnected.
- Connect an ohmmeter between engine speed sensor connector terminal 1 (engine control module side) and ground.
- The ohmmeter should read 15 - 25 ohms.

If reading is OK:
^ Proceed to Checking Short-circuit To Supply Voltage In Signal Cable section below.

If value is lower:
^ Check cable between engine speed sensor terminal 1 and control module # A20 for a short-circuit to ground.
^ Then proceed to Verification section below.

If value is higher:
^ Proceed to test step below.





Checking The Engine Control Module Connector
- Ignition off.
- Engine speed sensor disconnected.
- Check engine control module connector for contact resistance and oxidation and remedy.
- Engine control module connected.
- Connect an ohmmeter between engine speed sensor connector terminal 1 (engine control module side) and ground.
- The ohmmeter should read 15 - 25 K ohms.

If reading is OK:
^ The diagnostic trouble code (DTC) was caused by loose connections in the engine control module connector.
^ Then proceed to Verification section below.

If reading is incorrect:
^ Check cable between engine speed sensor terminal 1 and engine control module # A20 for an open-circuit.
^ Then proceed to Verification section below.





Checking Short-circuit To Supply Voltage In Signal Cable
- Ignition on.
- Engine speed (RPM) sensor disconnected.
- Connect a voltmeter between engine speed sensor connector terminals 1 and 2 (engine control module side).
- The voltmeter should read 1 - 2 Volts.

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

If reading is incorrect:
^ Check cable between engine speed sensor terminal 1 and engine control module # A20 for a short-circuit to supply voltage.
^ Then proceed to Verification section below.





Checking The Engine Control Module Connector
- Ignition off.
- Check engine speed sensor connector for contact resistance and oxidation and remedy.
- Try to start the engine.
- Does the engine start?

Yes:
^ The engine did not start because of loose connections in the engine speed sensor and/or engine control module connectors. Check connectors for contact resistance and oxidation and remedy.
^ Then proceed to Verification section below.

No:
^ Check carrier plate/flywheel for damage and scratches through the engine speed sensor hole. If no faults are detected on the carrier plate/flywheel: Try a new engine speed sensor.
^ Then proceed to Verification section below.





Verification
- After carrying out the repair, check that the fault has been remedied as follows.
- Ignition off.
- Reconnect connectors and reinstall components.
- Try to start the engine.
- Does the engine start?

Yes:
^ Fault corrected.

No:
^ 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 Engine Speed Sensor Resistance section above.