Signal Too Low

Signal too low

Checking the function of the engine coolant temperature sensor




- Ignition on.
Read off the engine coolant temperature.
Compare the engine coolant temperature with the engine temperature. The temperatures must be more or less the same.





Continue - Checking the component and wiring

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Checking the component and wiring








- Ignition off
- Disconnect the connector in the heater.
Check the terminals. Check for contact resistance. Check for loose connections. Check for oxidation.
Check the resistance of the engine coolant temperature sensor.
Check the cable between control module terminal #3 and the terminal for the engine coolant temperature (ECT) sensor. Check for a short-circuit to ground.
Check the cable between control module terminal #4 and the terminal for the engine coolant temperature (ECT) sensor. Check for a short-circuit to ground.
Remedy as necessary.

Other information
- Component specification [1][2]Auxiliary Cabin Heater
- Signal specification Signal Description, Combustion Preheater Module (CPM)
- Overheat protection thermostat/engine coolant temperature sensor, replacing Overheat Protection Thermostat/Engine Coolant Temperature Sensor, Replacing
- Checking wiring and terminals Checking Wiring and Terminals









Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off
- Reinstall the connectors, components etc.
- Ignition on
- Read off the engine coolant temperature.
Compare the engine coolant temperature with the engine temperature. The temperatures must be more or less the same.





Is the engine coolant temperature within its permitted range?

Yes - Troubleshooting procedure complete

No - Fault-tracing information

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit Fault-Tracing

No - Attempt New Test

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Attempt New Test - Checking the function of the engine coolant temperature sensor

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