DTC 1-4-3

1-4-3 FRONT KNOCK SENSOR, SIGNAL

Preconditions for DTC
^ If engine coolant temperature exceeds +40°C (1O4°F), engine rpm exceeds 2000 rpm, load exceeds 2.5 ms and the signal from the Knock Sensor (KS) is missing, the DTC for the relevant KS is set.

Substitute value
^ Knock control is inhibited.
^ Only initial charge pressure is allowed.
^ Dwell angle reduced for safety reasons.
^ Increase in quantity of injected fuel to cool the fuel/air mixture.

Fault sources
^ Incorrectly adjusted camshafts.
^ Signal lead short circuited to ground.
^ Break in signal or ground lead.
^ Contact resistance in connectors.
^ Defective knock sensor (KS).

Fault symptom
^ Poorer performance owing to initial charge pressure and/or lower ignition angle.

TESTING PROCEDURE





Status Message
^ Check current status message.

If Status message is: Permanent fault, faulty signal:
- Proceed to: PERMANENT FAULT, FAULTY SIGNAL section below.
If Status message is: Intermittent fault, faulty signal:
- Proceed to: INTERMITTENT FAULT, FAULTY SIGNAL section below.

PERMANENT FAULT, FAULTY SIGNAL





Checking the Camshaft Setting
^ Switch Ignition OFF.
^ Check camshaft setting in relation to the crankshaft.
^ Use gauge P/N 9995451, P/N 9995452 for checking.

If camshaft setting is OK:
- See Disconnection of knock sensor section below.
If the camshaft setting is NOT OK:
- Adjust the camshafts as necessary.





Disconnection of Knock Sensor
^ To gain access to the knock sensor connectors, remove the following:
^ Upper charge air cooler pipe.
^ Engine cooling fan.
^ Refit after fault tracing.
^ Continue with check of the ground lead.





Checking the Ground Lead
^ Switch Ignition OFF.
^ Wait for approx. 150 seconds.
^ Disconnect the knock sensor.
^ Connect an ohmmeter between knock sensor connector 2 and ground.

The ohmmeter should show approx. 0 ohms.

If reading is OK:
- Check the signal lead.
If reading is incorrect:
- Check the ECM's connector.





Checking the ECM's Connector
^ Switch Ignition OFF.
^ Knock sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.





^ ECM connected.
^ Connect an ohmmeter between knock sensor connector 2 and ground.

The ohmmeter should show approx. 0 ohms.

If reading is OK:
- Source of DTC is poor contact in ECM's connector.
If reading is incorrect:
- Check lead between knock sensor connector 2 and ECM A17 for signs of a break.





Checking the Signal Lead
^ Switch Ignition OFF.
^ Knock sensor disconnected.
^ Connect an ohmmeter between knock sensor connector 1 and ground.

The ohmmeter should show approx. 1M ohms.

If reading is OK:
- Check the Knock Sensor signal.
If ohmmeter shows infinite resistance:
- Check the ECM's connector.
If the ohmmeter shows approx. 0 ohms:
- Check lead between knock sensor connector 1 and ECM A2 for signs of short circuiting to ground.





Checking the ECM's Connector
^ Switch Ignition OFF.
^ Knock sensor disconnected.
^ Rectify the ECM connector with regard to contact resistance and oxidation.





^ ECM connected.
^ Connect an ohmmeter between knock sensor connector 1 and ground.

The ohmmeter should show approx. 1M ohms.

If reading is OK:
- Source of DTC is poor contact in ECM's connector.
If reading is incorrect:
- Check lead between knock sensor connector 1 and ECM A2 for signs of a break.





Checking the Knock Sensor Signal
^ Re-connect knock sensor.
^ START and warm up the engine.
^ Look at the DTC parameter.
^ REV the engine to slightly above 3500 rpm.





^ Read off the value on the Knock Sensor signal.

The value should be 2 - 6 at speeds above 3500 rpm.

If reading is OK:
- The source of the DTC is poor contact in the knock sensor connector. Rectify the connector with regard to contact resistance and oxidation.
If reading is incorrect:
- Test with a new knock sensor.

INTERMITTENT FAULT, FAULTY SIGNAL





Checking Camshaft Setting
^ Switch Ignition OFF.
^ Check camshaft settings in relation to the crankshaft.
^ Use gauge P/N 9995451, P/N 9995452 for checking.

If camshaft setting is OK:
- Check leads and connections.
If camshaft setting is NOT OK:
- Adjust the camshafts as necessary.





Checking the Leads And Connectors
^ Check the knock sensor and ECM's connector for signs of a loose connection and contact resistance and oxidation.
^ Check lead between knock sensor connector 1 and ECM A2 for signs of an intermittent break and intermittent short circuiting to ground.
^ Check lead between knock sensor connector 2 and ECM A17 for signs of an intermittent break.