M: Low Oil Pressure Warning Never/Always ON

M1 Check For Low Oil Pressure Warnings
- Start engine.
- Check displays.
- Determine if the warning is always on or never on.

Is low oil pressure warning always on?

Yes
GO to M2.
No
GO to M4.

M2 Check Oil Pressure Warning Lamp
- Turn ignition switch to RUN, engine off.
- Disconnect oil pressure switch connector C1025
- Check for warning.

Is low oil pressure warning illuminated?

Yes
GO to M3
No
REPLACE oil pressure switch. RESTORE vehicle. RETEST system.

M3 Check Circuit 31 (W/R)
- Turn ignition switch to OFF.
- Disconnect instrument cluster connector C251
- Using an ohmmeter connected to ground, measure resistance at Pin C251 , Circuit 31 (W/R)

Is resistance 10,000 ohms or less?

Yes
SERVICE Circuit 31 (W/R) for short to ground. RESTORE vehicle. RETEST system.
No
REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.

M4 Check For Power And Grounds
- Disconnect instrument cluster connectors C250 and C251
- Using a voltmeter, measure voltage at the following pins:

Connector Pin Function Voltage Circuit

C251 RUN or START B+ 608 (BK/Y)

C251 RUN or START B+ 1044(W/Y)

- Using an ohmmeter, measure resistance to a known good ground at Pin C250, Circuit 57 (BK).

Are all voltages and resistances as specified?

Yes
GO to M5.
No
SERVICE suspect circuit as required. RESTORE vehicle. RETEST system.

M5 Check Oil Pressure Switch Supply Circuit
- Turn ignition switch to OFF.
- Disconnect oil pressure switch connector C1025.
- Connect a jumper wire from Circuit 31 (W/R) at harness connector C1025 to ground.
- Turn ignition switch to RUN.
- Check low oil pressure for warning.

Is low oil pressure warning illuminated?

Yes
REPLACE oil pressure switch. RESTORE vehicle. RETEST system.
No
GO to M6.

M6 Check Resistance Of Circuit 31 (W/R)
- Remove jumper.
- Disconnect instrument cluster connector C251
- Using an ohmmeter, check resistance in Circuit 31 (W/R) between Pin C251 of instrument cluster and Circuit 31 (W/R) at oil pressure sensor connector C1025

Is resistance 3 ohms or less?

Yes
REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.
No
SERVICE Circuit 31 (W/R) for open circuit. RESTORE vehicle. RETEST system.