Faulty Signal

Faulty signal

Diagnostic trouble code (DTC) status ECM-640A Camshaft reset valve. Faulty signal

Reading off Diagnostic trouble code (DTC) status ECM-640A
Note! When reading off the diagnostic trouble code (DTC) status, other stored diagnostic trouble codes (DTCs) and their status will be listed.

- Read off the diagnostic trouble code (DTC) status. Check the status of the relevant diagnostic trouble code (DTC).





Was the status of the relevant diagnostic trouble code (DTC) permanent?

Yes - Checking the component

No - Checking the component

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Checking the component
Check the oil level and oil quality.
Check the mechanical function of the variable valve timing (VVT) unit and the reset valve.
Remedy as necessary

Other information:
- For the camshaft reset valve diagnostic functions, see Camshaft diagnostics. Description and Operation
- To access and replace the camshaft reset valve, see Variable valve timing solenoid, replacing Removal and Replacement
- For information about signals see Signal Specifications.





Was a fault detected?

Yes - Verification

No - Checking the component

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Checking the component
Check that the timing belt has not jumped off and that the camshaft is in the correct position.

Hint: Faults may result from dirt in the camshaft reset valve. Try cleaning the valve.

Try a new camshaft reset valve if the above fault-tracing does not solve the fault.
Remedy as necessary.

Other information:
- To clean the camshaft reset valve, see VVT solenoid, inspection and cleaning VVT Solenoid, Inspection and Cleaning
- For the camshaft reset valve diagnostic functions, see Camshaft diagnostics. Description and Operation
- To access and replace the camshaft reset valve, see Variable valve timing solenoid, replacing Removal and Replacement
- For information about signals see Signal Specifications.





Continue - Fault-tracing information

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Verification




Verification

Verification

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








- Ignition off.
- Reinstall the connectors, components etc.
- Start the engine.
Check the ACTUAL- and DESIRED- values when the control starts this takes approximately 2 minutes.
The ACTUAL value should follow the DESIRED- value.









Does the ACTUAL- value follow the DESIRED- value?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - Fault Found

VERIFICATION FAILED - 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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the component

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