2012 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P1239-ENGINE OIL TEMPERATURE TOO LOW

P1239-ENGINE OIL TEMPERATURE TOO LOW

For a complete wiring diagram, refer to the Wiring Information.



Possible Causes

ENGINE OIL
(G24) EOT SIGNAL CIRCUIT HIGH RESISTANCE
(K900) SENSOR GROUND CIRCUIT HIGH RESISTANCE
ENGINE OIL TEMPERATURE SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


1. DTC IS ACTIVE




NOTE: Diagnose any CAN C Communication DTCs before continuing.
1. Turn the ignition off.
2. If possible, allow the vehicle to sit with the ignition off for more than 60 minutes in an environment where the temperature will allow the oil temperature to cool down.
3. Start the engine and allow it to reach normal operating conditions.
4. With the scan tool, select View DTCs.


Is the status Active or Pending for this DTC?

Yes


No


2. ENGINE OIL


1.

The following conditions must be checked:



Were any of the above conditions found?

Yes


No


3. ENGINE OIL TEMPERATURE SENSOR VOLTAGE


1. Turn the ignition off.
2. Disconnect the Engine Oil Temperature Sensor harness connector.
3. Turn the ignition on.
4. With the scan tool, read the Engine Oil Temperature Sensor voltage.


NOTE: The sensor voltage should be approximately 5.0 Volts (plus or minus .1 Volt) with the connector disconnected.


Does the scan tool display the voltage as described above?

Yes


No


4. ENGINE OIL TEMPERATURE SENSOR



1. Turn the ignition off.
2. Connect a jumper wire between the (G24) EOT Signal circuit and the (K900) Sensor Ground circuit in the Engine Oil Temperature Sensor harness connector.
3. Turn the ignition on.
4. With the scan tool, read the Engine Oil Temperature Sensor voltage.


NOTE: The sensor voltage should be approximately 0.0 Volts (plus or minus .1 Volt) with the jumper wire in place.


Does the scan tool display the voltage as described above?

Yes


No


5. (G24) EOT SIGNAL CIRCUIT HIGH RESISTANCE



1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance of the (G24) EOT Signal circuit between the Engine Oil Temperature Sensor harness connector and the PCM C2 harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


6. (K900) SENSOR GROUND CIRCUIT HIGH RESISTANCE



1. Measure the resistance of the (K900) Sensor Ground circuit between the Engine Oil Temperature Sensor harness connector and the PCM C2 harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


7. POWERTRAIN CONTROL MODULE (PCM)


1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Engine Oil Temperature Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No