Faulty Signal

Faulty signal

Checking the component

Warning! The engine cooling fan (FC) can also operate if the ignition is switched off when this diagnostic trouble code (DTC) is stored.

Hint: To avoid injury, disconnect the power supply to the engine cooling fan (FC) during fault-tracing.

- Check the connector on the engine coolant temperature (ECT) sensor. Check for contact resistance and oxidation.

Hint: 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.

Other information
- Connecting the breakout box, B5254T7 Connecting The Breakout Box, Engine Control Module (ECM)
- Signal specification, B5254T7 Signal Specification
- Component specifications, B5254T7 [1][2]Engine Control Module
- Engine coolant temperature sensor (ECT), B5254T7 Service and Repair
- 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.








- Verification should begin with a cold engine (+20 °C) so that the engine coolant temperature (ECT) sensor can be tested over as wide a temperature range as possible
- Ignition off
- Reconnect the connectors, reinstall components etc.
- Start the engine.
Read off the engine coolant temperature (ECT) sensor signal.
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

FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the component

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