P1239

P1239-ENGINE OIL TEMPERATURE TOO LOW

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





Theory of Operation

The Engine Oil Temperature (EOT) sensor is a variable resistor that measures the temperature of the engine oil. It operates as a typical two wire sensor. The Powertrain Control Module (PCM) supplies the sensor with a 5-Volt reference and a sensor ground circuit. When the oil temperature is low, the sensor resistance is high. When the oil temperature is high, the sensor resistance is low.

- When Monitored:
The engine oil temperature has dropped below a calibrated temperature value. Engine start up.

- Set Condition:
The Engine Oil temperature rises slower than a calibrated modeled temperature. When the actual oil temperature falls below the low boundary of the calibrated modeled temperature the fault is set. Two trip fault.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC

NOTE: Diagnose and repair any system voltage DTCs before continuing with this test.

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 DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. 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

- Go To 3

No

- Go To 4

3. ENGINE OIL TEMPERATURE SENSOR
1. Turn the ignition off.
2. Connect a jumper wire between the (G24) EOT Sensor Signal circuit and the (K900) EOT Sensor Return circuit in the EOT 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 0.1 of a Volt) with the jumper wire in place.

Does the scan tool display the voltage as described above?

Yes

- Replace the Engine Oil Temperature Sensor. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. CHECK THE (G24) EOT SENSOR SIGNAL CIRCUIT FOR HIGH RESISTANCE
1. Turn the ignition off.
2. Connect the Engine Oil Temperature Sensor harness connector.
3. Using a Voltmeter, perform a voltage drop test by backprobing the (G24) EOT Sensor Signal circuit at the Engine Oil Temperature Sensor harness connector and back probing the (G24) EOT Sensor Signal circuit at the PCM C2 harness connector. Make sure the Voltmeter leads are connected so that positive polarity is displayed on the Voltmeter.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.

4. Start the engine.

Is the voltage below 0.5 of a Volt?

Yes

- Go To 5

No

- Repair the (G24) EOT Sensor Signal circuit for high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. CHECK THE (K900) EOT SENSOR RETURN CIRCUIT FOR HIGH RESISTANCE
1. Turn the ignition off.
2. Using a Voltmeter, perform a voltage drop test by backprobing the (K900) EOT Sensor Return circuit at the Engine Oil Temperature Sensor harness connector and back probing the (K900) EOT Sensor Return circuit at the PCM C2 harness connector. Make sure the Voltmeter leads are connected so that positive polarity is displayed on the Voltmeter.

WARNING:
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in possible serious or fatal injury.

3. Start the engine.

Is the voltage below 0.5 of a Volt?

Yes

- Go To 6

No

- Repair the (K900) EOT Sensor Return circuit for high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. 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

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace the Powertrain Control Module (PCM). .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.