The engine oil pressure switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the engine control module (ECM) should detect a low signal voltage input. With the engine running, the engine oil pressure switch opens and the ECM should detect a high signal voltage input. When the oil pressure is low, the ECM sends a message via High Speed CAN-Bus to the body control module (BCM). The BCM then sends a message via Low Speed CAN-Bus to the instrument cluster requesting the engine oil pressure indicator turned ON.

The engine is running.

The instrument cluster illuminates the service vehicle soon indicator and the oil pressure low indicator.

The DTC becomes history when the conditions for setting the DTC are no longer present.

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Ignition ON, observe the scan tool Engine Oil Pressure Switch parameter with the ignition switch turned ON and the engine not running the reading should be Low, with the engine running the reading should be OK.

1. Ignition OFF, disconnect the harness connector at the B37 Engine Oil Pressure Switch.
2. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.

⇒	If not the specified value, test for the signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

•	Terminal 1 except LDK

•	Terminal A with LDK

3. Install a 3 A fused jumper wire between the signal circuit terminal listed below and ground. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

•	Terminal 1 except LDK

•	Terminal A with LDK

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module (ECM).

4. If all circuits test normal, test or replace the B37 Engine Oil Pressure Switch.

Static Test

1. Ignition OFF, disconnect the harness connector at the B37 Engine Oil Pressure Switch.
2. Test for infinite resistance between the signal terminal listed below and ground with the switch in the open position.

•	Terminal 1 except LDK

•	Terminal A with LDK

⇒	If not the specified value, replace the B37 Engine Oil Pressure Switch.

3. Test for less than 5 Ω between the signal terminal listed below and ground with the switch in the closed position.

•	Terminal 1 except LDK

•	Terminal A with LDK

⇒	If greater than the specified range, replace the B37 Engine Oil Pressure Switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.