GM Service Manual Online
For 1990-2009 cars only

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.
  4. 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.
  5. Connect a 3 amp fusiable link between the signal circuit of the EOT and the low reference circuit.
  6. 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