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) OIL PRESSURE SWITCH

Fig 1: Checking Oil Pressure Switch
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Oil Pressure Switch harness connector.

Ignition on, engine not running.

Connect a jumper wire to the (G6) Oil Pressure Signal circuit in the Sensor harness connector.

With the scan tool monitor the Oil Pressure Switch state.

Touch the other end of the jumper wire to a known good Ground several times.

Did the Oil Pressure Switch state change from High to Low when connecting and disconnecting the jumper wire to ground?

Yes
1. Replace the Oil Pressure Switch.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 3).
  NOTE: Remove the jumper wire before continuing.
3) (G6) OIL PRESSURE SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

Fig 2: Checking Oil Pressure Switch Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C1 PCM harness connector.

Ignition on, engine not running.

Measure the voltage on the (G6) Oil Pressure Signal circuit in the Switch harness connector.

Is the voltage above 0 volts?

Yes
1. Repair the short to battery voltage on the (G6) Oil Pressure Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 4).
4) (G6) OIL PRESSURE SWITCH SIGNAL CIRCUIT OPEN

Fig 3: Checking Oil Pressure Switch Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

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 (G6) Oil Pressure Signal circuit from the Oil Pressure Switch 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 (G6) Oil Pressure Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
5) (G6) SIGNAL CIRCUIT SHORTED TO GROUND

Fig 4: Checking Oil Pressure Switch Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between a known good ground and the (G6) Oil Pressure Signal circuit in the Switch connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (G6) Oil Pressure Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 6).
6) PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes
1. Repair as necessary.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Replace and program the Powertrain Control Module per Service Information.
2. Perform POWERTRAIN VERIFICATION TEST .