Faulty Signal
Faulty signal
Checking the function of the combustion fan
Note! On cars where the heater functions as a parking heater there is no +15 voltage supply to the control module. Individual components and functions cannot be activated when the +15 voltage supply is absent.
- 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 the connectors
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Checking the connectors
Note! On cars where the heater functions as a parking heater there is no +15 voltage supply to the control module. Individual components and functions cannot be activated when the +15 voltage supply is absent.
- Ignition off
- Check the electrical terminals on the combustion fan and the control module connector. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Remedy if necessary.
Check for damage carefully
- Reinstall the components, reconnect the connectors etc.
- Ignition on
- Activate the combustion fan.
Listen for a buzzing sound which indicates that the combustion fan is running.
If the combustion fan now operates, the cause of the fault was loose connections in the connectors.
Other information:
- Remove the heater according to Replacing heat exchanger Service and Repair to access the combustion fan. Remove the fan shroud.
Does the combustion fan function?
Yes - FAULT FOUND
No - Replacing the component
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Replacing the component
- Ignition off.
Try a new combustion fan according to Replacing fuel injection nozzle, fan motor and nozzle pipe Service and Repair.
Continue - Verification
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
Note! On cars where the heater functions as a parking heater there is no +15 voltage supply to the control module. Individual components and functions cannot be activated when the +15 voltage supply is absent.
- Ignition off
- Reinstall the connectors, components etc.
- 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 - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - 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 - Exit fault-tracing
No - Attempt New Test
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Attempt New Test - Checking the function of the combustion fan
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Intermittent fault
- Ignition off.
Check the electrical terminals on the combustion fan and the control module connector. Check for contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Other information:
- Remove the heater according to Replacing heat exchanger Service and Repair to access the combustion fan. Remove the fan shroud.
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
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