Electronic Control System Gas Plus Engines – 019-156   Oil Pressure/Temperature Circuit

The engine oil pressure/temperature sensor circuit consists of the +5 VDC supply wire, signal wire for pressure, signal wire for temperature, and return wire in the engine harness.

Disconnect engine harness ECM connector 1 from the ECM and check for damaged pins.

Disconnect the engine oil pressure/temperature sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the engine oil pressure secondary +5 VDC supply (1) pin in engine harness ECM connector 1 to the corresponding pin in the engine harness sensor connector.

The multimeter must show a closed circuit (10 ohms or less).

If the circuit is not closed, there is an open circuit in the supply wire.

Repair or replace the engine harness. Refer to Procedure 019-205, 019-204, or 019-043.

Measure the resistance from the engine oil pressure/temperature return pin in engine harness ECM connector 1 to the corresponding pin in the engine harness sensor connector.

The multimeter must show a closed circuit (10 ohms or less).

If the circuit is not closed, there is an open circuit in the return wire. Repair or replace the engine harness. Refer to Procedure 019-205, 019-204, or 019-043.

Measure the resistance from the engine oil pressure signal pin in engine harness ECM connector 1 to the corresponding pin in the engine harness sensor connector.

Then, measure the resistance from the engine oil temperature signal pin in engine harness ECM connector 1 to the corresponding pin in the engine harness sensor connector.

The multimeter must show a closed circuit (10 ohms or less) for both checks.

If either circuit is not closed, there is an open circuit in the applicable signal wire. Repair or replace the engine harness. Refer to Procedure 019-205, 019-204, or 019-043.

Disconnect engine harness ECM connector 1 from the ECM. Disconnect the engine oil pressure/temperature sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the engine oil pressure/temperature return pin in engine harness ECM connector 1 to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the return wire.

Repair or replace the engine harness. Refer to Procedure 019-204, or 019-043.

Measure the resistance from the engine oil pressure signal pin in engine harness ECM connector 1 to engine block ground.

Measure the resistance from the engine oil temperature signal pin in engine harness ECM connector 1 to engine block ground.

The multimeter must show an open circuit (100k ohms or more) for both signal wire checks.

If the circuit is not open, there is a short circuit to ground in the applicable signal wire. Repair or replace the engine harness. Refer to Procedure 019-204, or 019-043.

Measure the resistance from the engine oil pressure +5 VDC supply (1) pin in engine harness ECM connector 1 to engine block ground.

The multimeter must show an open circuit (100k ohms or more).

If the circuit is not open, there is a short circuit to ground in the supply wire. Repair or replace the engine harness. Refer to Procedure 019-204, or 019-043.

Disconnect engine harness ECM connectors 1 and 2 from the ECM. Disconnect the engine oil pressure/temperature sensor from the engine harness. Set the multimeter to measure resistance.

Measure the resistance from the engine oil pressure signal pin in engine harness ECM connector 1 to all other pins in the connector and to all pins in engine harness ECM connector 2.

Repeat the pin-to-pin check from the engine oil temperature signal pin in engine harness ECM connector 1 to all other pins in the connector and to all pins in engine harness ECM connector 2.

The multimeter must show an open circuit at all pins.

If any pin-to-pin check does not show an open circuit, there is a short circuit between the applicable pins.

Repair or replace the engine harness. Refer to Procedure 019-204, or 019-043.