Faulty Signal
Faulty signal
Status check
- Start the engine.
Check that the tachometer is working. Try increasing the engine speed. Check that the tachometer readings are within their permitted range.
Does the engine coolant temperature (ECT) gauge display a faulty value, or a value outside its permitted range?
Yes - Replacing the component
No - Information
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Replacing the component
- Start the engine.
Check the tachometer signal from the engine control module (ECM). Increase the engine speed (RPM) and check that the engine speed (RPM) from the engine control module (ECM) is within its permitted range.
If the incorrect value is noted it means that the engine control module (ECM) is defective. Replace the engine control module (ECM).
Note! In cars with the Melco 2 engine management system, the engine speed (RPM) signal comes directly from the ignition sensor in the engine management system.Diagnostic trouble codes (DTCs) are stored in the engine control module (ECM) if there is a fault in the ignition sensor. These diagnostic trouble codes (DTCs) must be fault-traced instead of replacing the engine control module (ECM).
If the correct value is noted from the engine control module (ECM) it means that the combined instrument panel is defective. Replace the combined instrument panel.
Remedy as necessary.
Other information:
- To connect the breakout box, see Connecting the breakout box Connecting the Breakout Box, Driver Information Module (DIM)
- To access and replace the combined instrument panel, see Driver information module, removing/installing Removal and Replacement
- For information about signals, see Signal specification Signal Specification, Driver Information Module (DIM).
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.
- Start the engine.
Check that the tachometer is working. Try increasing the engine speed. Check that the tachometer readings are within their permitted range.
Does the tachometer work? Is the value within its permitted range?
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 - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Replacing the component
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Information
The combined instrument panel has previously registered a fault in the engine speed (RPM) signal from the engine control module (ECM), but registers that the fault no longer exists.
Continue - Fault-tracing information
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Fault-tracing information
Information
Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).
Do you want to view the information again?
Yes - Attempt New Test
No - FAULT FOUND
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Attempt New Test - Information
FAULT FOUND - DONE
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