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. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Engine Oil Temperature Sensor Signal | 1 | 1 | 1 | -- |
Engine Oil Temperature Sensor Low Reference | -- | 1 | -- | -- |
1. Engine Oil Temperature Indicator Always On | ||||
Circuit/System Description
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 instrument panel cluster (IPC) interfaces with the engine oil temperature sensor via a discreet signal circuit and low reference circuit. The IPC applies 5 volts to the engine oil temperature sensor through an internal input resistor that is connected to the signal circuit of the engine oil temperature sensor. The internal resistor in the IPC measures the voltage and calculates temperature. The engine oil temperature range is between -40 to -165°C (-40 to +329°F).
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the engine oil temperature sensor.
- Ignition OFF, test for less than 1 ohm between the low reference circuit terminal listed below and ground.
- Ignition ON, verify the scan tool Engine Oil Temperature Calculated parameter is less than -10°C (+14°F).
- Ignition ON, install a 3A fused jumper wire between the signal circuit terminals and the low reference circuit terminals listed below. Verify the scan tool Engine Oil Temperature Calculated parameter is greater than 150°C (302°F).
- If all circuits test normal, test or replace the engine oil temperature sensor.
| • | Low Reference Terminal A (LS7) |
| • | Low Reference Terminal C (LS2) |
| ⇒ | 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 listed below for a short to ground. If the circuit tests normal, replace the IPC. |
| • | Signal Terminal B (LS7) |
| • | Signal Terminal B (LS2) |
| • | Signal Terminal B (LS7) |
| • | Signal Terminal B (LS2) |
| • | Low Reference Terminal A (LS7) |
| • | Low Reference Terminal C (LS2) |
| ⇒ | 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 IPC. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for the IPC replacement, setup, and programming |
