The low oil pressure warning lamp will illuminate anytime the ignition switch is turned to the ON
position without the engine running. When the engine is running, the light also illuminates if the engine oil pressure drops below a safe oil pressure level. To test the system, perform the following:
If the oil pressure light does not work, perform the following:
- Turn the ignition switch to the ON position.
- If the lamp does not light, check for a broken or disconnected wire around the engine and oil pressure sending unit switch.
- If the wire at the connector checks out OK, pull the connector loose from the switch and, with a jumper wire, ground the connector to the engine.
- With the ignition switch turned to the ON position, check the warning lamp. If the lamp lights, make sure the oil pressure switch is properly grounded in the cylinder block, and if so replace the oil pressure switch. If the lamp still fails to light, check for a burned out lamp or disconnected socket in the instrument cluster.
To diagnose an oil pressure light that stays on, perform the following:
- Check the engine oil level and top off as necessary. If the engine was 2 or more quarts low on oil, test start the engine after topping off the oil level and recheck the oil pressure light operation. If the light stays on, stop the engine immediately and go to the next step.
- Disconnect the wire at the sending unit, then turn the ignition switch to theON position. If the light remains on, check the wire from the sending unit to the gauge for being shorted to ground and repair as necessary. If the light goes out, turn the ignition switch OFF and go to the next step.
- Replace the oil pressure sending switch with a known good switch.
- Start the engine and check the oil pressure light operation. If the light stays on with the engine running, stop the engine immediately to avoid severe engine damage until the cause of the problem can be determined.
If the oil pressure light remains on while the engine is started, stop the engine immediately. Do not operate the engine until the cause of the problem can be determined. Operating an engine with low oil pressure will cause severe internal damage.
Possible causes for an oil pressure light to stay on are:
Pinched or grounded sensor wireDefective oil pressure sending unitRestricted or severely leaking oil filterExcessive internal engine bearing clearance.Insufficient or severely contaminated engine oilBlocked oil pump pickup screen or severely worn oil pump