Engine Oil Pressure Switch Diagnosis. Buick Regal 1999

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1999 🢒 Regal 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Engine Oil Pressure Switch Diagnosis

Engine Oil Pressure Switch Diagnosis

Engine Controls Components
Cell 21: Engine Oil Level, Engine Oil Pressure and IAC
Handling ESD Sensitive Parts Notice
OBD II Symbol Description Notice

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 2 serial data to the Instrument Panel Cluster (IPC). The IPC controls the Engine Oil Pressure Indicator.

Diagnostic Aids

Check for the following condition(s):

•	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 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

Value(s)

Yes

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check .

Are any PCM DTCs stored?

Go to Applicable DTC

Go to Step 3

Is the engine oil pressure indicator ON?

Go to Step 4

Go to Step 16

Check the engine for correct oil level. Refer to Fluid and Lubricant Recommendations in Maintenance and Lubrication.

Is the correct engine oil level indicated?

Go to Step 5

Go to Step 11

Check the engine oil pressure with a manual pressure gauge.

Refer to Oil Pressure Diagnosis and Testing in Engine Mechanical.

Is proper engine oil pressure indicated?

Go to Step 6

Go to Step 12

Turn OFF the ignition switch.
Disconnect the engine oil pressure switch connector.
Turn ON the ignition switch.
Connect a J 35616-200 test lamp to ground.
Probe cavity A in the oil pressure switch connector.

Is the test lamp ON?

Go to Step 7

Go to Step 9

Connect the test lamp to B+.
Probe cavity B in the oil pressure switch connector.

Is the test lamp ON?

Go to Step 8

Go to Step 10

Check for poor terminal connections in the oil pressure switch.
If a problem is found, repair as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Was a problem found?

Go to Step 16

Go to Step 13

Check for the following circuit condition(s):

•	Open or short to ground in the PCM feed to the engine oil pressure switch.

•	Poor connections at the PCM.

If a problem is found, repair as necessary. Refer to Wiring Repairs or Repairing Connector Terminals in Wiring Systems.

Was a problem found?

Go to Step 16

Go to Step 15

Locate and repair the following circuit condition(s):

•	Open in the engine oil pressure ground.

•	Poor terminal connections in the Underhood Electrical Center pass-through connector.

Refer to Wiring Repairs or Repairing Connector Terminals in Wiring Systems.

Is action complete?

Go to Step 16

Determine cause of low oil.

Is action complete?

Go to Step 16

Determine cause of low oil pressure. Refer to Oil Consumption Diagnosis in Engine Mechanical for diagnosis.

Is action complete?

Go to Step 16

Check the communication circuit for correct operation.

Was a problem found?

Go to Step 16

Go to Step 14

Replace Engine Oil Pressure switch. Refer to Engine Oil Pressure Sensor and/or Switch Replacement .

Is action complete?

Go to Step 16

Important: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Is action complete?

Go to Step 16

Check for the proper operation of Oil Pressure Indicator.

Is the correct operation indicated?

System Ok

Go to Step 2