Faulty Signal. Permanent Fault

Faulty signal. Permanent fault

Checking the engine coolant temperature (ECT)

Note! This diagnostic trouble code (DTC) is stored if the engine coolant temperature (ECT) sensor freezes. This may happen if the coolant level is low or there is too little glycol in the coolant. Check the engine coolant level and its freezing point. Remedy as necessary.




- Fault-tracing must begin with the engine cold (+20 °C) so that the engine coolant temperature (ECT) sensor can be tested over as wide a temperature range as possible
- Switch off the climate control unit
- Start the engine.
Read off the engine coolant temperature (ECT).
Check that the engine coolant temperature (ECT) is within its permitted range and corresponds with the engine warming up.









Is the temperature within its permitted range?

Yes - Checking the thermostat

No - Replacing the component

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Checking the thermostat




- Start the engine. Run the engine until the engine coolant temperature (ECT) reaches approximately 100°C
- Activate the engine cooling fan (FC) with the engine running
- Wait approximately 90 seconds and then shut-off the engine cooling fan (FC).
Read off the engine coolant temperature (ECT). If it is 85°C or lower when the fan stops, the thermostat is defective.









Is the temperature 85°C or lower when the fan stops?

Yes - Replacing the component

No - FAULT-TRACING FAILED

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Replacing the component
Replace the thermostat. See Check/replacing thermostat .






Continue - FAULT FOUND

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Replacing the component
Replace engine coolant temperature (ECT) sensor. See Engine temperature sensor Engine Temperature Sensor.






Continue - Verification

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Verification




Verification

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








- Fault-tracing must begin with the engine cold (+20 °C) so that the engine coolant temperature (ECT) sensor can be tested over as wide a temperature range as possible
- Ignition off
- Reconnect connectors, reinstall components etc.
- Start the engine
- Read off the engine coolant temperature.
Check that the engine coolant temperature (ECT) is within its permitted range and corresponds with the engine warming up.





Is the temperature within its permitted range?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - FAULT FOUND

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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 engine coolant temperature (ECT)

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