Engine Oil Pressure Sensor/Switch A Circuit

What it means

The engine computer has detected an improper signal from the oil pressure sensor or switch circuit. This code usually points to an electrical problem in the sensor or its wiring, but real low oil pressure can only be ruled out by measuring it with a mechanical gauge.

Related codes: P0521P0522P0523P0524

Symptoms4

• Check engine light on.
• Oil pressure warning light comes on or flickers for no clear reason, or does not work.
• Oil pressure gauge does not move or fluctuates on vehicles that have one.
• On some vehicles, automatic engine stop-start stops working.

Possible causes6

• Failed oil pressure sensor or switch.
• Oil leaking through the sensor into its connector and corroding the pins.
• Open or shorted sensor wiring.
• Loose or corroded connector.
• Genuinely low oil level or pressure.
• Engine computer fault (rare).

How to diagnose5

1. Check the oil level and condition first.
2. Watch the oil pressure reading on a scan tool at idle and at higher engine speed.
3. Inspect the sensor and connector for oil leakage or corrosion.
4. Measure supply, ground and signal voltages at the connector and compare with the manufacturer specification.
5. Fit a mechanical pressure gauge in place of the sensor to confirm the real pressure.

How to fix5

1. Top up or change the oil if it is low or old.
2. Clean or replace the connector if oil has reached it.
3. Repair damaged wiring.
4. Replace the oil pressure sensor.
5. Clear the codes and confirm the pressure reading and oil light work normally.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is usually low because the sensor is relatively cheap; it rises a little when the sensor is hard to reach or the connector and wiring need repair.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions