Signal Too Low

Signal too low

Checking the function of the water pump




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





Is the combustion fan working?

Yes - Checking components and wiring

No - Checking components and wiring

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





Is the combustion fan working?

Yes - VERIFIED

No - VERIFICATION FAILEDPAPER

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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 function of the water pump

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Checking components and wiring
- Check the cable between combustion preheater module (CPM) terminal #10 and the signal terminal for the combustion fan (the black lead from the fan). Check for an open-circuit. Check for a short-circuit to ground
- Check the cable between combustion preheater module (CPM) terminal #11 and the voltage terminal for the combustion fan (the red cable from the fan). Check for an open-circuit.

Note! Diagnostic trouble codes (DTC) CEM-5F3A and/or CEM-5F3F may also be stored if there is a fault in the power cable.

The combustion fan must be replaced if no faults are found in the cable.
Remedy as necessary.

Other information
- Connecting the breakout box Connecting the Breakout Box
- Signal specification Signal Specification
- Fuel injection nozzle / fan motor / pressure equalizer, replacing Fuel Injection Nozzle / Fan Motor / Pressure Equalizer, Replacing
- Checking wiring and terminals Checking Wiring And Terminals






Continue - Verification

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Checking components and wiring
- Check the electrical terminals for the combustion fan and the combustion preheater module (CPM) connector. Check for contact resistance and oxidation
- Check the cable between combustion preheater module (CPM) terminal #10 and the signal terminal for the combustion fan (the black lead from the fan). Check for an intermittent open-circuit. Check for an intermittent short-circuit to ground
- Check the cable between combustion preheater module (CPM) terminal #11 and the voltage terminal for the combustion fan (the red cable from the fan). Check for an intermittent open-circuit.
Remedy as necessary.

Other information
- 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
- Signal specification Signal Specification
- Water pump engine coolant heater, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals






Continue - Verification

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