Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Engine Coolant Temperature Sensor Monitoring

ENGINE COOLANT TEMPERATURE SENSOR MONITORING

The engine coolant temperature is electrical O.K., if the following condition is true:

Diagnosis threshold min. < engine coolant temperature < Diagnosis threshold max.

RangeCheck






PlausibilityCheck lowside
The engine coolant temperature is plausible, if:

(reference temperature - threshold) < engine coolant temperature






PlausibilityCheck highside
The engine coolant temperature is plausible, if:






(engine coolant temperature - reference temperature) > threshold

Stuck Signal Check
The engine coolant temperature is plausible if - after subsequent periods of vehicle operation at high and low cooling condition, respectively - a certain amount of variability in the engine coolant temperature signal is observed.
(engine coolant temperature(max) - engine coolant temperature(min) > threshold.






flow chart: