Signal Too High

Signal too high

Checking the function of the combustion fan




- Ignition on
- Activate the 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 components and wiring

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Checking components and wiring
Check the cable between control module terminal #10 and the signal terminal for the combustion fan (the black lead from the fan). Check for a short-circuit to supply voltage.
If no faults are found in the cable, the combustion fan must be replaced. See Fuel injection nozzle / fan motor / pressure equalizer, replacing Fuel Injection Nozzle / Fan Motor / Pressure Equalizer, Replacing.
Remedy as necessary.

Other information:
- To access the control module or connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- With the ignition on and the signal terminal for the combustion fan disconnected, the voltage between the signal terminal for the combustion fan (control module side) and ground must be approximately 0 V
- For other values, see Signal specification Signal Specification
- Checking wiring and terminals Checking Wiring And Terminals.










Continue - Verification

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Verification




Verification

Verification

Hint: After the repair it is necessary to check that the fault has been rectified.








- Ignition off.
- Connect connector, install components etc.
- Ignition on.
- Activate the heater fan.
Listen for a buzzing sound indicating that the heater fan is working.





Is the heater fan working?

Yes - VERIFIED

No - VERIFICATION FAILEDPAPER

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VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

PAPER - No 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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the function of the combustion fan

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

Other information:
- To access the control module or connect the breakout box, see Connecting the breakout box Connecting the Breakout Box
- To access the combustion fan, see Fuel injection nozzle / fan motor / pressure equalizer, replacing Fuel Injection Nozzle / Fan Motor / Pressure Equalizer, Replacing
- With the ignition on and the signal terminal for the combustion fan disconnected, the voltage between the signal terminal for the combustion fan (control module side) and ground must be approximately 0 V
- For other values, see Signal specification Signal Specification.










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 the function of the combustion fan

FAULT-TRACING FAILED - DONE

FAULT FOUND - Fault Found

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