B131 Engine Oil Pressure Circuit Problem

Code B131 - Engine Oil Pressure Circuit Problem:

Wiring Diagram for Code B131 - Engine Oil Pressure Circuit Problem:

CODE B131 - ENGINE OIL PRESSURE CIRCUIT PROBLEM

Circuit Description:

Important!

If the vehicle you are working on is equipped with gages, you are on the wrong chart. See code Chart B131 and/or B132 Engine Oil Pressure Sensor circuit problem.

The oil pressure indicator (without gages) uses a switch to control the signal voltage to the BCM. The BCM supplies a voltage on CKT 313 to the switch. When the engine is running, oil pressure holds the switch contacts open, therefore, the BCM will see a high signal voltage. As oil pressure drops, the switch contacts close and the signal voltage is pulled lo through sensor ground (switch is case grounded).

Code B131 will set during "display-on-entry", if the signal voltage is HI (open CKT). In other words, when the engine is not running, oil pressure is low and the switch contacts should close and pull the signal voltage low. A shorted to ground circuit will show up as low oil pressure all the time.



Test Description:

1. BCM input B126 displays off pressure at HI or LO, depending on the voltage state at the BCM.

2. Checks to see if the HI reading is due to the circuit or the switch. With the engine off, if the display changes from HI to LO, when the connector is jumpered to ground, the BCM and wiring are OK.

3. Checks to see if the HI reading is due to the BCM or the circuit If the display changes from HI to LO, when BCM terminal cavity is backprobed to ground, the BCM is OK.



Note on Intermittents:

If an intermittent code B131 is being set, manipulate CKT 313. When BCM input B126 change-of-state indicator displays an "x", the failure has been induced.