Engine Oil Temperature Sensor Circuit

What it means

The oil temperature sensor measures engine oil temperature, which the engine computer uses to calculate oil life, control variable valve timing (VVT) and, on some cars, protect the engine when it runs hot. The computer has found a fault in this sensor's circuit and uses an estimated value instead of the real reading.

Related codes: P0196P0197P0198P0199P0520

Symptoms4

• Check engine light on.
• Implausible oil temperature on the gauges or scan tool.
• Oil change reminder may be inaccurate.
• Changed cooling fan or valve timing behavior on some vehicles.

Possible causes5

• Oil leaking into the connector or through the sensor itself.
• Wiring or connector damaged by heat.
• Failed oil temperature sensor.
• On some cars the sensor is combined with the oil level or oil pressure sensor and fails with it.
• Engine computer fault (rare).

How to diagnose5

1. Find the sensor location and type per the manufacturer; it may be in the oil pan, in the engine block or combined with another sensor.
2. After the engine has sat for hours, compare oil temperature with coolant and outside air temperatures; they should be close.
3. Inspect the connector for oil or corrosion.
4. Check reference voltage and ground, then measure sensor resistance against the manufacturer chart.
5. If the circuit is sound and the reading is implausible, replace the sensor.

How to fix4

1. Clean oil from the connector and fix the source of the leak.
2. Repair damaged wiring or connector.
3. Replace the oil temperature sensor, topping up or changing the oil if fitting requires draining it.
4. Clear the codes and confirm the reading rises normally as the engine warms.

Repair cost

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

Cleaning the connector or repairing a wire is cheap; the cost rises when the sensor sits in the oil pan and the oil must be drained, or when it is combined with the oil level sensor.

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