For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category

### DTC Descriptors

DTC P0196: Engine Oil Temperature Sensor Circuit Range/Performance
DTC P0197: Engine Oil Temperature Sensor Circuit Low Input
DTC P0198: Engine Oil Temperature Sensor Circuit High Input

### Circuit/System Description

The engine oil temperature (EOT) sensor is a variable resistor that measures the temperature of the engine oil. The engine control module (ECM) supplies a 5 voltage to the EOT signal circuit and supplies a ground for the reference circuit.

### Conditions for Running the DTC

#### P0112, P0196 or P0198

• | The engine has been running for more than 10 seconds.

• | This DTC runs continuously within the enabling conditions.

### Conditions for Setting the DTC

#### P0196

The ECM detects that the engine EOT sensor is not within 100°C of predetermined values.

#### P0197

The ECM detects that the EOT sensor is less than -35°C of longer than 3 seconds.

#### P0198

The ECM detects that the EOT sensor is greater than 170°C for longer than 3 seconds.

### Action Taken when the DTC Sets

DTCs P0196, P0197 and P0198 are type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0196, P0197 and P0198 are type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

Inspect condition of oil system. Refer to Oil Pressure Diagnosis and Testing.

### Circuit/System Testing

#### P0196, P0197 or P0198

1. Ignition ON, engine OFF.
2. Disconnect the EOT sensor.
3. Measure for proper voltage range of 4.9-5.2 Volts.

⇒ | If the voltage is less than 4.9 volts, test the EOT sensor circuit for a short to ground or an open/high resistance.

⇒ | If the voltage is greater than 5.2 volts, test the EOT circuit for a short to voltage.

⇒ | If the EOT circuit tests normal and the voltage is not within the proper range then replace the ECM.

4. Connect a 3 amp fusiable link between the signal circuit of the EOT and the low reference circuit.

⇒ | Observe the sensor parameters while connecting and disconnecting the link between the EOT sensor signal and the low reference circuit.

⇒ | the EOT should switch between the upper and lower limits.

⇒ | if the EOT signal does not switch between the upper and lower limits then replace the ECM..

⇒ | if the EOT signal does switch between the upper and lower limits then replace the EOT.

### Component Testing

Measure and record the resistance of the EOT sensor at various temperatures and then compare those measurements to the Temperature Versus Resistance Table. Refer to Temperature Versus Resistance - Engine Coolant Temperature Sensor.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup and programming