Is it safe to drive with a P0118 code?

Severity is medium. Address P0118 sooner rather than later — driving with an active check engine light can worsen the problem or void emissions warranties.

How much does it cost to fix P0118?

Repair costs for P0118 typically range from $15 to $150 in the US, depending on the underlying cause. The most common fix is: Disconnected ECT connector.

What are the symptoms of P0118?

Check engine light. Cold-start hard / no-start. Cooling fans running at low temp. Erratic gauge.

Check Engine Code

P0118

Engine Coolant Temperature Sensor Circuit High Input

Severity: medium DIY difficulty: 1/5 Typical cost: $15–$150

Last updated April 30, 2026

What P0118 means

Counterpart to P0117. ECM is seeing an open circuit or implausibly hot coolant reading from the ECT sensor.

Vehicle-specific P0118 guides

P0118 can mean different things on different vehicles. Pick your make for engine-family specifics:

P0118 on Chevy → P0118 on Toyota →

Symptoms

Check engine light
Cold-start hard / no-start
Cooling fans running at low temp
Erratic gauge

Likely causes (most common first)

Disconnected ECT connector
Open ECT sensor
Broken signal wire
Corroded pins

Can I keep driving?

Medium — drivable but fix soon

Typical repair cost

DIY fixes can start near $15 (parts only). Shop repairs for P0118 typically run up to $150 depending on the underlying cause and vehicle. Start with the most common cause — Disconnected ECT connector — before throwing parts at it.