Engine Oil Pressure Sensor Diagnosis

Circuit Description

The engine oil pressure sensor is a solid state transducer. The engine oil pressure sensor sends oil pressure information to the PCM. The PCM then transmits the oil pressure information to the PC via serial data (CKT 1807).

Engine oil pressure is displayed on the scan tool in volts. A low voltage reading indicates low oil pressure. As the oil pressure increases, the voltage level also increases. The normal range of the engine oil level sensor signal voltage is 0.5 volts at 0 kPa (0 psi) to 4.5 volts at 883 kPa (128 psi).


Diagnostic Aids

For diagnosis of the instrument panel, refer to the Instrument Panel System Check in Electrical Diagnosis.

Check for the following conditions:

^ Poor connection at the PCM or the engine oil pressure sensor.

Inspect harness connectors for the following conditions:

- Backed out terminals.

- Improper mating.

- Broken locks.

- Improperly formed or damaged terminals.

- Poor terminal to wire connection.

^ Damaged harness.

Inspect the wiring harness for damage.

^ Instrument panel cluster.

The Engine Oil Pressure Sensor diagnostic table is intended to isolate electrical faults that affect the engine oil pressure sensor, the PCM, and related circuits. If a problem with engine oil pressure can not be isolated using the Engine Oil Pressure Sensor diagnostic table, refer to the Instrument Cluster System Check in Electrical Diagnosis.


Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. Normal engine oil pressure sensor signal voltage is between 0.5 volt at 0 kPa (0 PSI) and 4.5 volts at 883 kPa (128 PSI). If engine oil pressure sensor voltage is within range, determine the cause of incorrect oil pressure. Refer to Engine Mechanical Diagnosis.

4. If the engine oil pressure signal voltage stays high with the engine oil pressure sensor electrical connector disconnected, the signal circuit is shorted to voltage or the PCM is malfunctioning.

22. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.