Signal Too High

Signal too high

Checking combustion fan function




- Ignition on.
- Activate combustion fan.
Listen for a buzzing sound which indicates that the combustion fan is running.





Does the combustion fan function?

Yes - Intermittent fault

No - Checking component and cables

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Checking component and cables
Check cable between control module #10 and combustion fan signal terminal (black lead from fan) for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
If no faults are found in the cable the combustion fan should be replaced according to Replacing fuel injection nozzle, fan motor and nozzle pipe Service and Repair.
Remedy as necessary.

Other information:
- To access the control module/connect breakout box see.
- To access the combustion fan, position heater in service mode according to Moving the heater to its service position Procedures and remove fan shroud.
- With ignition on and combustion fan signal disconnected the voltage between combustion fan signal terminal (engine control module (ECM) side) and ground should be approximately 0 V.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.













Continue - Verification

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Verification




Verification

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








- Ignition off.
- Reinstall connectors, components etc.
- Ignition on.
- Activate combustion fan.
Listen for a buzzing sound which indicates that the combustion fan is running.





Does the combustion fan function?

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 - Checking combustion fan function

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Intermittent fault
Check cable between control module #10 and combustion fan signal terminal (black lead from fan) for a short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Remedy as necessary.

Other information:
- To access the control module/connect breakout box see.
- To access the combustion fan, position heater in service mode according to Moving the heater to its service position Procedures and remove fan shroud.
- With ignition on and combustion fan signal disconnected the voltage between combustion fan signal terminal (engine control module (ECM) side) and ground should be approximately 0 V.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.














Continue - Fault-tracing information
DONE

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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 - Checking combustion fan function

FAULT-TRACING FAILED - DONE

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