Ask Andy AIP0118 Engine Coolant Temperature Circuit High
What it means, what causes it, and what it costs to fix.
What P0118 means
The coolant temperature sensor's voltage reads as extremely cold. That's usually an open circuit or a failed sensor, not an actual cold engine.
Can I drive with P0118?
Severity: Medium. Fix soon so it doesn't turn into something bigger.
Drivable, but the engine may run rich, start hard, and the cooling fans may run constantly. Keep an eye on the real temperature gauge.
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Ask Andy about P0118Symptoms
- Cooling fans run all the time
- Black smoke or fuel smell
- Hard starting
- Bad fuel economy
- Gauge reads cold
Common causes
Most likely first.
- Failed coolant temp sensor
- Unplugged or corroded connector
- Broken wire
How to diagnose P0118
- Compare the scan tool coolant temperature with the actual engine temperature.
- Unplug and inspect the connector.
- Test sensor resistance and wiring.
Tip: most US auto parts stores will read your codes for free.
Repair costs
| Coolant temp sensor | $80–$250 installed |
| Wiring or connector repair | $50–$200 |
Typical US prices. Your vehicle, region, and shop rates will change these.
P0118 FAQ
What does P0118 mean?
P0118 means "Engine Coolant Temperature Circuit High." The coolant temperature sensor's voltage reads as extremely cold. That's usually an open circuit or a failed sensor, not an actual cold engine.
Can I drive with a P0118 code?
Drivable, but the engine may run rich, start hard, and the cooling fans may run constantly. Keep an eye on the real temperature gauge.
What is the most common cause of P0118?
The most common cause is: Failed coolant temp sensor. Other causes include unplugged or corroded connector and broken wire.
How much does it cost to fix P0118?
Typical repairs run about $50 to $250 in the US, depending on the cause. Coolant temp sensor: $80–$250 installed.
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