Diagnostic Test

1) GOOD TRIP INDICATED
NOTE: Record the Freeze Frame Information that set along with the DTC.

Turn the ignition on.

With the scan tool, read DTCs.

Does the Good Trip Indicator display NO?

Yes
1. Go To 2).
No
1. Refer to the INTERMITTENT CONDITION diagnostic procedure.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
2) (K42) OR (K942) KNOCK SENSOR CIRCUIT SHORTED TO VOLTAGE

Fig 1: CHECKING KNOCK SENSOR CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Knock Sensor harness connector.

Measure the voltage of the (K42) Knock Sensor Signal circuit and the (K942) Knock Sensor Return circuit in the Knock Sensor harness connector.

Is the voltage above 2.0 volts on either circuit?

Yes
1. Repair the short to voltage in the (K42) or (K942) Knock Sensor circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 3).
3) (K42) OR (K942) KNOCK SENSOR CIRCUIT SHORT TO GROUND

Fig 2: MEASURING RESISTANCE BETWEEN GROUND AND KNOCK SENSOR CIRCUITS
Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the PCM harness connector.

Measure the resistance between ground and the (K42) and (K942) Knock Sensor circuits in the Knock Sensor harness connector.

Is the resistance to ground below 100 ohms on either circuit?

Yes
1. Repair the short to ground in the (K42) or (K942) Knock Sensor circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 4).
4) (K42) KNOCK SENSOR SIGNAL OPEN

Fig 3: MEASURING RESISTANCE OF KNOCK SENSOR SIGNAL CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (K42) Knock Sensor Signal circuit between the Knock Sensor harness connector and the PCM harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Go To 5).
No
1. Repair the open (K42) Knock Sensor Signal circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
5) (K42) KNOCK SENSOR SIGNAL SHORTED TO (K942) KNOCK SENSOR RETURN CIRCUIT

Fig 4: MEASURING RESISTANCE BETWEEN THE KNOCK SENSOR SIGNAL CIRCUIT AND KNOCK SENSOR RETURN CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between the (K42) Knock Sensor Signal circuit and the (K942) Knock Sensor Return circuit in the Knock Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to (K942) Knock Sensor Return circuit in the (K42) Knock Sensor Signal circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 6).
6) (K942) KNOCK SENSOR RETURN CIRCUIT OPEN

Fig 5: MEASURING RESISTANCE OF THE KNOCK SENSOR RETURN CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (K942) Knock Sensor Return circuit between the Knock Sensor harness connector and the PCM harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Go To 7).
No
1. Repair the open (K942) Knock Sensor Return circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
7) KNOCK SENSOR
Turn the ignition off.

Replace the Knock Sensor.

Reconnect the PCM harness connectors.

Turn the ignition on.

With the scan tool, erase DTC.

Attempt to operate the vehicle using the information noted in the Freeze Frame.

With the scan tool, read DTC's.

Does the scan tool display the DTC that was previously erased?

Yes
1. Replace and program the Powertrain Control Module in accordance with the Service Information. (Refer to STANDARD PROCEDURE - PCM/ECM/SKREEM PROGRAMMING) .
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Test Complete.