P0126

P0126

Engine Coolant Temperature Circuit Problem










Fault symptoms
- CHECK ENGINE.
- A/C not working.
- Radiator fan runs continuously when ignition is ON.
- Temperature gauge reading incorrect.
- Misfiring can occur before trouble code is generated.

On-Board Diagnostics

Type of diagnosis:
- Once per driving cycle. Interrupted when fault criteria fulfilled or OK reported. Restarts next driving cycle.

Enable criteria:
- A temperature model is calculated with an accumulated air mass at 25°C and a DTC is generated if the sensor value is more than 5°C lower than the substitute value or 100°C higher than the substitute value.

Fault criteria:
- Sensor value more than 5°C lower than the substitute value or more than 100°C higher than the substitute value.

Dependents:
- P0117 and P0118.

System reaction to a fault:
- Switches to a limp-home temperature, which goes up to max. 106°C.

OK report:
- Test performed once, the fault criteria are not fulfilled and diagnostics for P0117 & P0118 reported OK.

Fault handling: (See Fault diagnosis, general for more information.)
- Type III.

Diagnostic help
Fault diagnosis concerns an electrical fault in connecting leads or in the sensor.

Functions in the diagnostic tool related to the fault:
- Diagnostic status for the diagnosis.
- Temperature sensor reading, in °C.
See also description of read value under "Read Values" menu for more information.

Check the wiring
Jiggle the wiring harness at several points and in several directions to check for intermittent breaks and short circuiting.