Engine Oil Pressure Switch Diagnosis
Refer to
Oil Pressure Sensor, IAC, PNP, and Generator
in Engine Controls Schematics.
Circuit Description
The PCM applies battery voltage through a pull up resistor to the Engine Oil Pressure Switch circuit. The PCM monitors the applied voltage on the Engine Oil Pressure Switch circuit. If the ignition switch is turned ON with the engine not running or engine oil pressure is below 35 kPa (5 psi), the Engine Oil Pressure switch grounds the PCM voltage input. The PCM sends the engine oil pressure information via Class II serial data to the Instrument Panel Cluster (IPC). The IPC controls the Engine Oil Pressure Indicator.
Diagnostic Aids
Inspect for the following conditions:
| • | Poor connections. Inspect PCM and harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. |
| • | Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the Engine Oil Pressure switch, turn the ignition ON, with the engine OFF and observe a voltmeter connected between the Engine Oil Pressure switch connector terminals while moving wiring harnesses related to the Engine Oil Pressure Switch circuit. A change in voltage will indicate the location of the fault. |
Engine Oil Pressure Switch Diagnosis
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | |
2 |
Does the oil pressure lamp illuminate? | -- | Go to Step 4 | Go to Step 3 |
3 | With the scan tool, observe the oil pressure parameter. Does the oil pressure read LOW? | -- | Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and Console | Go to Step 7 |
4 | Disconnect the oil pressure switch connector. Is the oil pressure lamp OFF? | -- | Go to Step 5 | Go to Step 10 |
5 |
Important:: Shut OFF the engine immediately if the oil pressure lamp illuminates with the engine running. Is the engine oil pressure lamp OFF? | -- | Go to Step 16 | Go to Step 6 |
6 |
Is the oil pressure OK? | -- | Go to Step 14 | Go to Oil Pressure Diagnosis and Testing in Engine Mechanical |
7 |
Does the fused jumper open? | -- | Go to Step 12 | Go to Step 8 |
8 |
Does the oil pressure read LOW? | -- | Go to Step 14 | Go to Step 9 |
9 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
10 |
Does the oil pressure lamp turn OFF as commanded? | -- | Go to Step 11 | Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges, and console |
11 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 13 |
12 | Repair the short to voltage on the oil pressure input circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 16 | -- |
13 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 |
14 | Replace the Engine Oil Pressure switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical. Did you complete the replacement? | -- | Go to Step 16 | -- |
15 |
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- |
16 | Operate the vehicle within the conditions which the original symptom was noted. Does the system now operate proper? | -- | System OK | Go to Step 2 |
