P0118

TORQDEX // POWERTRAIN DTC

Engine Coolant Temperature Sensor 1 Circuit High Input

The engine coolant temperature sensor signal is above the expected electrical range.

CODE FAMILY Powertrain
SEVERITY MODERATE
DRIVEABILITY GENERALLY DRIVEABLE
COMMON AREA ECT Sensor / Wiring

00 // CODE DEFINITION

What P0118 means

P0118 indicates a coolant-temperature signal voltage above the expected range, often interpreted as an implausibly cold engine.

An open sensor, disconnected connector, broken wire, or poor terminal connection may be responsible.

01 // COMMON SYMPTOMS

What you may notice

Check-engine light
Rich cold-start behavior
Poor fuel economy
Hard starting
Cooling fan strategy may change

02 // COMMON CAUSES

What can trigger P0118?

SENSOR

Open temperature sensor

The sensor may have failed internally.

CONNECTOR

Disconnected sensor

An unplugged connector can produce a high-voltage signal.

WIRING

Open circuit

Broken signal or ground wiring can create an implausibly cold reading.

03 // DRIVEABILITY

Can I keep driving with P0118?

SEVERITY MODERATE
GENERALLY DRIVEABLE

The vehicle may remain driveable depending on the symptoms. Diagnose the fault soon, especially if performance, fuel economy, starting, shifting, or engine operation has changed.

04 // DIAGNOSTIC ORDER

Start here

01

Review live temperature

Look for an unrealistically low coolant-temperature value.

02

Inspect the connector

Check whether the sensor is unplugged or terminals are damaged.

03

Check continuity

Verify signal and ground circuits.

04

Test sensor resistance

Compare the sensor with expected resistance at the measured temperature.

05 // COMMON REPAIR AREAS

Systems commonly involved

These are common areas associated with P0118. Testing should confirm the actual fault before parts are replaced.

SENSOR

Open temperature sensor

The sensor may have failed internally.

CONNECTOR

Disconnected sensor

An unplugged connector can produce a high-voltage signal.

WIRING

Open circuit

Broken signal or ground wiring can create an implausibly cold reading.

06 // DIAGNOSTIC PRINCIPLE

Confirm the fault before replacing parts

P0118 identifies a condition detected by the vehicle control system. It does not automatically identify one failed component. Test the affected system before replacing parts.

07 // RELATED TORQDEX DIAGNOSTICS

Related diagnostic guides

Continue troubleshooting by symptom and system. These TorqDex guides cover common diagnostic paths associated with this trouble code.