MasterTuning Fault code dictionary (DTC)

P0118 — Engine Coolant Temperature Sensor High Input

Severity: Warning Can you drive? With caution: limp mode possible, have it checked soon Make: All makes (OBD-II standard)
MeaningThe engine control unit has detected an abnormally high voltage signal from the coolant temperature sensor. This means the computer thinks the engine is running extremely cold, even if it has been running for a while.
FamilyPowertrain (P)

Typical symptoms

The engine cooling fan runs constantly at high speed
Hard starting when the engine is warm
Increased fuel consumption during normal driving

Common causes

Faulty coolant temperature sensor
Damaged, corroded, or shorted wiring to the sensor
Low coolant level in the cooling system

What to do

Check the coolant level first and inspect the sensor wiring harness for any obvious damage or loose connections. It is best to address this soon, as running with incorrect temperature data can affect overall engine operation.

Frequently asked questions

What does code P0118 mean?

Engine Coolant Temperature Sensor High Input. The engine control unit has detected an abnormally high voltage signal from the coolant temperature sensor. This means the computer thinks the engine is running extremely cold, even if it has been running for a while.

Can I keep driving with code P0118 active?

With caution: limp mode possible, have it checked soon

Common causes — P0118

Faulty coolant temperature sensor Damaged, corroded, or shorted wiring to the sensor Low coolant level in the cooling system

How do you fix code P0118?

Check the coolant level first and inspect the sensor wiring harness for any obvious damage or loose connections. It is best to address this soon, as running with incorrect temperature data can affect overall engine operation.

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