Refer to Engine Controls Schematics
PCM Engine Oil Level and Pressure Inputs
.
Circuit Description
The powertrain control module (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 the engine oil pressure is less than 35 kPa (5 psi), the engine oil pressure switch grounds the PCM voltage input. The PCM sends the engine oil pressure information via Class 2 serial data to the instrument panel cluster (IPC). The IPC controls the Engine Oil Pressure indicator.
Diagnostic Aids
Use the J 35616 connector test adapter kit for any test that requires probing the PCM harness connectors, electrical center fuse/relay cavities, component terminals or a component harness connector. Using this kit will prevent damage caused by improper probing of connector terminals.
If the problem is intermittent, refer to Intermittent Conditions for diagnosis.
Check for the following conditions:
| • | Any poor connections -- Inspect the PCM and harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connections. |
| • | A 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, and observe a voltmeter connected between the engine oil pressure switch connector terminals while moving the wiring harnesses related to the engine oil pressure switch circuit. A change in voltage will indicate the location of the fault. |
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||||||
2 | Turn the key to On, with the engine Off. Does the scan tool indicate Engine Oil Pressure Low? | -- | ||||||
3 | Start the engine. Does the scan tool indicate Engine Oil Pressure OK? | -- | Go to Diagnostic Aids | |||||
4 |
Is the correct engine oil level indicated? | -- | ||||||
5 | Check the actual engine oil pressure with a pressure gauge. Refer to Oil Pressure Diagnosis and Testing in Engine Mechanical. Is correct engine oil pressure indicated? | -- | ||||||
6 |
Does the scan tool indicate Engine Oil Pressure OK? | -- | ||||||
7 |
Does the scan tool indicate Engine Oil Pressure Low? | -- | ||||||
8 | Jumper terminal A of the connector to a known good ground. Does the scan tool indicate Engine Oil Pressure Low? | -- | ||||||
9 | Check for a short to ground in the PCM feed to the engine oil pressure switch Was a problem found and corrected? | -- | ||||||
10 | Repair the open on the ground circuit of the engine oil pressure switch . Refer to Wiring Repairs in Wiring Systems. Is the action complete? | -- | -- | |||||
11 | Determine the cause of the low oil level. Refer to Oil Leak Diagnosis or to Oil Consumption Diagnosis in Engine Mechanical. Is the action complete? | -- | -- | |||||
12 | Determine the cause of the low oil pressure. Refer to Oil Pressure Diagnosis and Testing in Engine Mechanical. Is the action complete? | -- | -- | |||||
13 | Check for the following conditions:
Refer to Wiring Repairs or Connector Repairs in Wiring Systems. Was a problem found and corrected? | -- | ||||||
14 | Replace the engine oil pressure switch. Is the action complete? | -- | -- | |||||
15 |
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | |||||
16 |
Does the scan tool indicate Engine Oil Pressure Low with the key On and the engine Off, and then OK with the engine running? | -- | System OK |
