Faulty Signal. Permanent Fault

Disconnecting Knock Sensors
- To access knock sensor (KS) connectors, remove the Engine cooling fan (FC)
- For rear knock sensor remove the Intake manifold support bracket.

Then continue with:
^ Proceed to test step below.





Checking Ground Lead
- Ignition off.
- Wait for approx. 150 seconds (cars with immobilizer 245 seconds).
- Disconnect knock sensor.
- Connect an ohmmeter between knock sensor connector terminal 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 The Engine Control Module Connector
- Ignition off.
- Knock sensor disconnected.
- Check engine control module (ECM) connector for contact resistance and oxidation and remedy.
- Engine control module connected.
- Connect an ohmmeter between knock sensor connector terminal 2 and ground.
- The ohmmeter should read approx. 0 ohms.

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

If reading is incorrect:
^ Check cable between knock sensor connector terminal 2 and engine control module # A17 for an open-circuit.
^ Then proceed to Verification section below.





Checking Signal Cable
- Ignition off.
- Knock sensor disconnected.
- Connect an ohmmeter between knock sensor connector terminal 1 and ground.
- The ohmmeter should indicate approx. 1M ohms

If reading is OK:
^ Proceed to Checking Knock Sensor Signal section below.

If value is lower:
^ Check cable between knock sensor terminal 1 and engine control module # A2 (EFI- 143) or # A30 (EFI-433) 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.
- Knock sensor disconnected.
- Check engine control module connector for contact resistance and oxidation and remedy.
- Engine control module connected. Connect an ohmmeter between knock sensor connector terminal 1 and ground.
- The ohmmeter should indicate approx. 1M ohms.

If reading is OK:
^ The diagnostic trouble code was caused by poor contact in the engine control module connector.
^ Then proceed to Verification section below.

If reading is incorrect:
^ Check cable between knock sensor terminal 1 and engine control module # A2 (EFI-143) or # A3O (EFI-433) for an open-circuit.
^ Then proceed to Verification section below.





Checking Knock Sensor Signal
- Ignition off.
- Connect the knock sensor.
- Start engine and run up to working temperature.
- Go into scrolling values list.
- Rev engine to 3,500 rpm. Read off the knock sensor signal value.
- This value should be 2 - 6 at engine speeds above 3,500 rpm.

If reading is OK:
^ The diagnostic trouble code has been caused by poor contact in the knock sensor connector. Check connector for contact resistance and oxidation and remedy.
^ Then proceed to Verification section below.

If reading is incorrect:
^ Try a new knock 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, reinstall components etc.
- Start engine and run up to working temperature.
- Go into scrolling values list.
- Rev engine to 3,500 rpm.
- Read off the knock sensor value.
- This value should be 2 - 6 at engine speeds above 3,000 rpm.

If reading is OK:
^ Fault corrected.

If reading is incorrect:
^ 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 Disconnecting Knock Sensors section above.