P0195
P0195-ENGINE OIL TEMPERATURE SENSOR CIRCUIT
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The PCM compares the start temperatures from the sensors of Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), Intake Air Temperature 2 (IAT2) and Engine Oil Temperature (EOT) under cold start conditions. If there is no hardware fault and no range/performance fault found with each of the sensors then the IAT and IAT2 sensor values are compared with each other and the ECT and EOT sensor values in a series of rationality tests. There are five main stages to the diagnostic: start up of temperature rationality test; read of start temperatures from EOT, ECT, IAT and IAT2 sensors; condition check for temperature rationality test; rationality tests for ECT, EOT and General Temperature, and Intake Air Temperature rationality test; OBD reporting for temperature rationality test.
- When Monitored:
Battery voltage between 11.0 and 16.0 volts. Engine off time greater than 9 hours. No diagnosed hardware faults with EOT, ECT, IAT or IAT2 sensors. Start temperatures read for EOT, ECT, IAT, IAT2 sensors. Engine run time greater than 40 seconds. IAT correlation test, ECT range/performance test, EOT range/performance test have run this ignition cycle.
- Set Condition:
IAT correlation test passed this ignition cycle. ECT range/performance test, EOT range/performance test passed this ignition cycle. IAT sensor start temperature exceeds EOT sensor start temperature by more than 20° C ( 68° F) and the difference between IAT sensor start temperature and ECT sensor start temperature is less than 10° C (50° F). IAT sensor start temperature is above the temperature threshold to detect that the block heater is switched off (-17.8° C - 0.0° F) and IAT sensor start temperature exceeds ECT start temperature by less than 10° C (50° F) and EOT sensor start temperature exceeds IAT sensor start temperature by more than 20° C (68° F). Two trip fault, three good trips required to reset the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
Diagnostic Test
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 480 minutes in an environment where the temperature is consistent and above -7° C (19.4° F).
3. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
4. With a scan tool, select View DTCs.
Is the status Active or Pending for this DTC?
Yes
- Go To 3
No
- Go To 2
2. AMBIENT AIR TEMPERATURE
1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -7° C (19.4° F) until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With a scan tool, compare the battery temperature, ECT, and IAT sensor values.
Is the Engine Oil Temperature Sensor value within 10° C (18° F) of the other two sensor values?
Yes
- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.
No
- Go To 3
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 a 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 4
No
- Go To 5
4. ENGINE OIL TEMPERATURE SENSOR
1. Turn the ignition off.
2. Connect a jumper wire between the EOT Signal circuit and the Sensor Ground circuit in the Engine Oil Temperature Sensor harness connector.
3. Turn the ignition on.
4. With a 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
- Replace the Engine Oil Temperature Sensor. .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. EOT SIGNAL CIRCUIT 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 EOT Signal circuit at the Engine Oil Temperature Sensor and Powertrain Control Module (PCM) harness connectors. 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 fitting clothing. Failure to follow these instructions can result in personal or fatal injury.
4. Start the engine.
Is the voltage below 0.5 volt?
Yes
- Go To 6
No
- Repair the EOT Signal circuit for high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
6. SENSOR GROUND CIRCUIT HIGH RESISTANCE
1. Turn the ignition off.
2. Using a voltmeter, perform a voltage drop test by backprobing the Sensor Ground circuit at the Engine Oil Temperature Sensor and Powertrain Control Module (PCM) harness connectors. 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 fitting clothing. Failure to follow these instructions can result in personal or fatal injury.
3. Start the engine.
Is the voltage below 0.5 volt?
Yes
- Go To 7
No
- Repair the Sensor Ground circuit for high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
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 a DTC to set 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.