P0116

Engine Coolant Temperature Sensor 1 Circuit Range/Performance

Car Fault Codes Cooling & lubrication

Can you still drive? With care, short trips only

Who can fix it? DIY with some experience

Typical repair time 20 minutes – 2.5 hours

Typical cost SAR 80 to 600

What it means

The engine computer checks the engine coolant temperature (ECT) reading against what it expects, such as matching intake air temperature after a long rest and rising at a logical rate after starting. If the reading is illogical, jumps or does not rise as it should, it sets this code; the cause may be the sensor, the thermostat or the coolant level.

Symptoms5

Check engine light on.
Temperature gauge behaving abnormally or staying low.
Weak cabin heating in cold weather.
Higher fuel consumption.
Occasional hard hot starting.

Possible causes5

Coolant temperature sensor whose resistance has drifted with age.
Thermostat stuck open, so the engine does not warm up at the expected rate.
Low coolant or an air pocket around the sensor.
Extra resistance in the connector from corrosion.
Fault in the intake air temperature sensor it is compared with.

How to diagnose5

Check the coolant level with the engine cold and make sure there is no air in the system.
After the car has sat for several hours, compare coolant temperature with intake air temperature; they should be close.
Watch the reading rise after starting; a very slow rise points to a thermostat stuck open.
Measure engine temperature with an external thermometer and compare it with the sensor reading.
Inspect the connector for corrosion or coolant residue.

How to fix5

Top up the coolant and bleed air from the system.
Clean or replace the connector.
Replace the thermostat if it is proven stuck open.
Replace the coolant temperature sensor if its reading does not match the real temperature.
Clear the codes and confirm the temperature rises to normal and stays there.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

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

The cost is low for a coolant top-up or a new sensor, and rises when the thermostat is replaced, especially if it is hard to reach.

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

Could the thermostat be the cause instead of the sensor?

Yes. A thermostat stuck open makes the engine warm up slowly, so the computer sees an illogical sensor reading even though the sensor is fine.

Is this code dangerous?

Not immediately, but an inaccurate reading can hide real overheating, so check the coolant and watch the gauge until it is fixed.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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