Engine Coolant Temperature Sensor Circuit High Input

What it means

The coolant temperature sensor is sending a higher voltage than normal, so the computer believes the engine is extremely cold or the circuit is open. The computer relies on this sensor for radiator fan control and fueling, so do not ignore it.

Symptoms5

• Dash temperature gauge reads very low or does not move.
• Radiator fan running constantly as a failsafe on some cars.
• Hard starting and higher fuel consumption.
• Black smoke or fuel smell from a rich mixture.
• Check engine light on.

Possible causes4

• Unplugged or corroded sensor connector.
• Broken wire between the sensor and computer.
• Failed sensor.
• Coolant level so low that the sensor is not immersed.

How to diagnose and fix5

1. Check the coolant level, only with the engine cold.
2. Inspect the sensor connector and wiring.
3. Compare the scan tool temperature reading with the actual engine temperature.
4. Replace the sensor if its reading is implausible and the wiring is sound.
5. After the repair, confirm the fan switches on when the engine reaches normal temperature.

Repair cost

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

The sensor is inexpensive and usually quick to replace, keeping the cost in the lowest tier.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.

Frequently asked questions