• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Engine Oil Temperature Sensor Signal Circuit | 1 | 1 | 1 | -- |
Engine Oil Temperature Sensor Low Reference Circuit | -- | 1 | -- | -- |
1. Engine Oil Temperature Indicator Always On |
The engine oil temperature sensor is a thermistor that varies in resistance as the engine oil temperature changes. A low engine oil temperature produces a high resistance at the engine oil temperature sensor. A high engine oil temperature produces a low resistance at the engine oil temperature sensor. The engine control module (ECM) monitors the engine oil temperature sensor via a discreet signal circuit and low reference circuit. The ECM applies 5 volts to the engine oil temperature sensor and calculates temperature based on the engine oil temperature sensor voltage. The engine oil temperature range is between -40°C (-40°F) to -165°C (329°F).
Control Module References for scan tool information.
⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. |
⇒ | If greater than the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the ECM. |
⇒ | If less than the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for the ECM replacement, setup, and programming |