Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) ACTIVE DTC
Ignition on, engine not running.

With a scan tool, read DTCs.

Is the DTC active at this time?

Yes
1. Go To step 2).
No
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
2) (K242) KNOCK SENSOR NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

Fig 1: Checking Knock Sensor No. 2 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the No.2 Knock Sensor harness connector.

Disconnect the C2 PCM harness connector.

Ignition on, engine not running.

Measure the voltage on the (K242) Knock Sensor No.2 Signal circuit in the Knock Sensor harness connector.

Is the voltage above 2.0 volts?

Yes
1. Repair the short to battery voltage in the (K242) Knock Sensor No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 3).
3) (K242) KNOCK SENSOR NO.2 SIGNAL CIRCUIT OPEN

Fig 2: Checking Knock Sensor No. 2 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K242) Knock Sensor No.2 Signal circuit from the Knock Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 4).
No
1. Repair the open in the (K242) Knock Sensor No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
4) (K924) KNOCK SENSOR NO.2 RETURN CIRCUIT OPEN

Fig 3: Checking Knock Sensor No. 2 Return Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (K924) Knock Sensor No.2 Return circuit from the Knock Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 5).
No
1. Repair the open in the (K924) Knock Sensor No.2 Return circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
5) (K242) KNOCK SENSOR NO.2 SIGNAL CIRCUIT SHORTED TO THE (K924) KNOCK SENSOR NO.2 RETURN CIRCUIT

Fig 4: Checking Knock Sensor No.2 Signal Circuit & Return Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between the (K242) Knock Sensor No.2 Signal circuit and the (K924) Knock Sensor No.2 Return circuit in the Knock Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short between the (K242) Knock Sensor No.2 Signal circuit and the (K924) Knock Sensor No.2 Return circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 6).
6) (K242) KNOCK SENSOR NO.2 SIGNAL CIRCUIT SHORTED TO GROUND

Fig 5: Checking Knock Sensor No.2 Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between ground and the (K242) Knock Sensor No.2 Signal circuit in the Knock Sensor harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (K242) Knock Sensor No.2 Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 7).
7) KNOCK SENSOR
Replace the Knock Sensor.

Ignition on, engine not running.

With the scan tool, erase DTC.

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

With the scan tool, read DTCs.

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

Yes

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary. Replace and program the Powertrain Control Module per Service Information.
1. Perform POWERTRAIN VERIFICATION TEST .
No
1. Test Complete.