Code B131 And/Or B132, Engine Oil Psi Sensor Circuit Problem: Notes

Fig 1: Code B131 and/or B132 Flowchart, Eng Oil Psi Sensor Ckt Prob

Fig 2: Code B131 and/or B132, Engine Oil Psi Sensor Circuit

Fig 3: Code B131 and/or B132 Schematic, Eng Oil Psi Sensor Ckt Prob

If the vehicle you are working on is not equipped with gauges, you are on the wrong chart. See Code B131, ENGINE OIL PRESSURE SWITCH CIRCUIT PROBLEM.

The oil pressure indicator (with gauges) uses a variable resistor to control the signal voltage to the BCM. The BCM supplies a voltage on circuit 313 to the sensor. When the engine is not running (low oil pressure), the sensor's resistance is low and the signal voltage is pulled low through the sensor ground, circuit 736 (short circuit). When the engine is running (increased oil pressure), the sensor's resistance becomes greater and the signal voltage increases, therefore the BCM will see a "HIGH" signal voltage (open circuit). This signal voltage will vary between 5 volts (open circuit) and 0 volts (shorted circuit).

Code B131 will set during "Display-on-Entry" if the signal voltage indicates greater than 8 psi (open circuit). Code B132 will set if the engine is running and the signal voltage indicates greater than 80 psi (open circuit).

1. If only Code B131 is set, the sensor is off and needs replacement.
2. BCM data value BD71 displays oil pressure. The normal range is from 0-80 psi.
3. Checks to see if the open circuit reading is due to the circuit or the sensor. If the open circuit reading changes to a shorted circuit reading after jumping the sensor terminals, the BCM and wiring are okay.
4. By applying a ground to various points in the circuits, an open can be isolated by observing whether the parameter display can be changed from the open reading to the shorted reading.