Engine Oil Sensors

Parent topic: Electrical Maintenance

Engine Low Oil Pressure Switch

Note The engine oil pressure switch is located near the oil filter, behind the starter motor.

Engine oil pressure should rise immediately when the engine starts. This causes the oil pressure switch to open. If the oil pressure drops below 5.6 – 9.9 psig (38 – 69 kPa), the switch will close. This causes the ECU to signal a shutdown to stop the engine. A continuity tester is needed to check the oil pressure switch. To check switch continuity complete the following steps when the engine is OFF:

  1. Remove wire connector from the switch.

  2. Continuity tester should indicate a complete circuit between the terminal and ground.

  3. Start the engine. Tester should show an open circuit between each terminal and ground. Repair consists of replacing the switch.

1. Engine Starter
2. Engine Oil Pressure Switch
3. Oil Filter

Engine Oil Level Sensor

If the engine oil level drops below a safe level, the low oil level sensor (OLS) switch will close. This will cause the ECU to signal to shutdown to stop the engine. The oil level switch is located in the oil pan on the front side of the engine near the oil filter.

1. Oil Level Switch Location

Switch Test:

  1. Turn the unit ON/OFF switch to the “OFF” position.

  2. Disconnect the switch wires from the main wire harness.

  3. Connect a continuity tester to the two sockets in the low oil level switch wire connector.

  4. Check the oil level with the dipstick. Make sure that it is between the low mark and the full mark. Add oil if necessary.

  5. The switch should be open and there should be no continuity between the switch wires. (When the oil level is between the low mark and the full mark on the dipstick).

Bench test the switch if there is continuity between the OLS and CH wires and there are no short circuits in the wires.


Switch Removal and Installation:

  1. Disconnect the switch wires from the main wire harness before removing the switch.

  2. Remove the screw-in style switch by carefully turning it out of the oil pan with a wrench.

  3. To install the screw-in style switch, first lubricate the O-ring on the switch with engine oil. Then screw the switch into the oil pan.

  4. Connect the switch wires to the main wire harness after installing it.


Bench Test:

  1. Disconnect the switch wires from the main wire harness. Remove the switch from the oil pan.

  2. Use a small container partially filled with engine oil to check the float. Make sure that it floats in engine oil and that it slides freely between the upper and lower stops.

  3. Slide the float up to the upper stop. Check the continuity through the switch (between OLS and CH wires). The switch should be open.

  4. Slide the float down to the lower stop. Check the continuity through the switch. The switch should be closed.

  5. Replace the switch if the float sinks or does not slide freely, or if the switch does not open and close properly.