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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Impala 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Engine Oil Pressure Switch Diagnosis

Object Number: 515280 Size: SF
Engine Controls Component Views
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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 conditions:

    • Poor connections -- Inspect PCM and harness connectors for the following conditions
       - Backed out terminals
       -  Improper mating
       -  Broken locks
       - Improperly formed or damaged terminal
       - 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 ON the ignition and observe a Digital Multimeter 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.

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Are any other DTCs stored?

--

Go to Diagnostic Trouble Code (DTC) List/Type

Go to Step 3

3

With the engine running, is the engine oil pressure Indicator ON?

--

Go to Step 4

Go to Step 16

4

Inspect for correct oil level.

Is the correct oil level indicated?

--

Go to Step 5

Go to Step 11

5

Test 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

6
  1. Turn OFF the ignition.
  2. Disconnect the engine oil pressure switch connector.
  3. Turn ON the ignition with the engine OFF.
  4. Connect a test lamp to ground.
  5. Probe cavity A in the oil pressure switch connector.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 9

7
  1. Connect the test lamp to B+.
  2. Probe cavity B in the oil pressure switch connector.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 10

8
  1. Inspect for poor terminal connections at the oil pressure switch.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

9
  1. Test for the following circuit condition(s):
  2. Open or short to ground in the PCM feed to the engine oil pressure switch.
  3. Poor connections at the PCM.
  4. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

10

Test the engine oil pressure sensor ground for an open or high resistance.

Did you find and correct the condition?

--

Go to Step 16

--

11

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

Did you find and correct the condition?

--

Go to Step 16

--

12

Determine cause of low oil pressure. Refer to Oil Pressure Diagnosis and Testing in Engine Mechanical.

Did you find and correct the condition?

--

Go to Step 16

--

13

Test the serial data circuit for correct operation. Refer to Diagnostic Starting Point in Data Link Communications.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

14

Replace engine oil pressure switch.

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.

Did you complete the replacement?

--

Go to Step 16

--

16

Test for the proper operation of oil pressure indicator. Refer to Circuit Description.

Is the correct operation indicated?

--

System OK

Go to Step 2