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 (EOT) Sensor Circuit Performance
DTC P0197: Engine Oil Temperature (EOT) Sensor Circuit Low Voltage
DTC P0198: Engine Oil Temperature (EOT) Sensor Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
EOT Sensor Signal | P0198 | P0196, P0197 | P0197 | P0197 | P0196
EOT Low Reference | -- | P0196, P0197 | P0197 | -- | P0196

### Typical Scan Tool Data

#### Engine Oil Temperature Sensor

Circuit | Short to Ground | High Resistance | Short to Voltage
--- | --- | --- | ---
Operating Conditions: Engine running Parameter Normal Range: Varies with engine oil temperature
EOT Sensor Signal | 172°C (341°F) | -40°C (-40°F) | -40°C (-40°F)
Low Reference | -- | -40°C (-40°F) | -40°C (-40°F)

### 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 5 volts on the EOT signal circuit, and a ground to the low reference circuit.

Monitoring the engine oil temperature is necessary for optimal control of the cam actuators. The oil temperature is monitored from the dual function oil level switch and temperature sensor located in the oil pan.

### Conditions for Running the DTC

#### P0196

• | The engine speed is greater than 25 RPM.

• | The engine oil temperature EOT is -35 to +170°C (-31 to +338°F).

• | The DTC runs continuously when the above enable conditions are met for greater than 10 seconds.

#### P0197 and P0198

• | The ignition is ON, or the engine is operating.

• | The DTCs runs continuously when the above enable condition is met for greater than 2 seconds.

### Conditions for Setting the DTC

#### P0196

The ECM detects the actual EOT is 40°C (104°F) colder than the calculated EOT of the controller, for greater than 4 seconds or a cumulative time of 30 seconds.

#### P0197

The ECM detects the EOT is colder than -35°C (-31°F) for greater than 4 seconds or a cumulative time of 30 seconds.

#### P0198

The ECM detects the EOT is warmer than 170°C (331°F) for greater than 4 seconds or a cumulative time of 30 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.

### Diagnostic Aids

A high resistance in the circuits of the EOT sensor may set DTC P0196.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Definitions

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Engine operating, observe DTC information with a scan tool. DTCs P0196, P0197, or P0198 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EOT sensor.
2. Ignition OFF, remove the fuse that supplies B+ to circuit terminal 56 X2 of the ECM.
3. Test for less than 5 Ω 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.

4. Install the fuse that supplies B+ to circuit terminal 56 X2 of the ECM.
5. Ignition ON, verify the scan tool Engine Oil temperature Sensor parameter is colder than -35°C (-31°F).

⇒ | If greater than the specified range, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM.

Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.

6. Connect a 3 A fused jumper wire between the signal circuit terminal B and the low reference circuit terminal C. Verify the scan tool EOT Sensor parameter is warmer than 171°C (340°F).

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

7. If all circuits test normal, replace the EOT/oil level sensor assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming