The engine oil temperature (EOT) sensor is a variable resistor. The EOT sensor measures the temperature of the engine oil. Monitoring the engine oil temperature input is necessary for optimal control of the cam phasers. The oil temperature is monitored from a dual function oil level switch and temperature sensor located in the oil pan. The EOT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies bias 5-volts on the EOT signal circuit, and a ground for the EOT low reference circuit. When the EOT sensor is cold, the sensor resistance is high. When the engine oil temperature increases, the sensor resistance decreases. With high sensor resistance, the ECM detects a high voltage on the EOT signal circuit. With lower sensor resistance, the ECM detects a lower voltage on the EOT signal circuit.

P0197

P0198

P0197

The EOT sensor is more than 162°C (324°F)  for greater than 25 seconds.

P0198

The EOT sensor is less than -60°C (-76°F)  for more than 25 seconds.

DTCs P0197 and P0198 are Type B DTCs.

DTCs P0197 and P0198 are Type B DTCs.

Schematic Reference

Connector End View Reference

Electrical Information Reference

DTC Type Definitions

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Important: Perform this verification procedure only if the ignition has been OFF for 10 hours or more.

1. Ignition ON, observe the scan tool IAT Sensor, EOT Sensor, and ECT Sensor parameters. The readings should be within 15°C (27°F) of each other and also the ambient temperature.
2. Engine running, observe the DTC information with a scan tool. DTCs P0197 or P0198 should not set.
3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the EOT sensor.
2. Test for less than 5 ohms of resistance between the low reference circuit terminal C and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, measure for a voltage range of 4.8-5.2 volts between the EOT signal circuit terminal B and a ground.

⇒	If less than the specified range, test the signal circuit for a short to ground, open/high resistance. If the circuit tests normal, replace the ECM.

⇒	If more than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Ignition OFF, disconnect the harness connectors at the ECM.
5. Test for infinite resistance between the oil temperature sensor signal circuit terminal B and the oil level switch signal circuit terminal A.

⇒	If less than the specified range, repair the short circuit between the oil temperature sensor signal circuit and the oil level switch signal circuit.

6. If all circuits test normal, replace the engine oil level sensor and/or switch assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.