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P0118 — Engine Coolant Temperature Sensor Circuit High
CautionCoolingLimp to the next safe stop
Seen on: Heavy Truck
Engine Coolant Temperature Sensor Circuit High. Common causes: ECT sensor open circuit.
Don't risk it — get a diesel tech on the truck.
Your code rides along, so nearby mechanics see the fault before they quote you.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- ECT sensor open circuit
- Broken wire
- failed sensor
First moves (roadside)
- Measure sensor resistance at operating temp
- should be 150-300 ohm
- replace if open
FAQ
What does P0118 mean?
Engine Coolant Temperature Sensor Circuit High. Common causes: ECT sensor open circuit.
How serious is P0118?
Caution — Limp to the next safe stop.
What's the most likely cause of P0118?
The most common cause is: ECT sensor open circuit. Other possibilities include Broken wire; failed sensor.
Can I keep driving with P0118?
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
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General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.