Signal Missing

Signal missing

Checking the status




- Ignition on.
Activate the heater.
On activation of the heater sequence, the heater starts up and operates for approximately 2 min 30 s. The fuel pump is activated after approximately 45 seconds. There must be a ticking sound from the fuel pump when it is activated.
The fault is permanent if the fuel pump does not start.
If the fuel pump starts, this is an indication that the fault was present previously but is not active at the moment, i.e. an intermittent fault.
Do not interrupt the heater sequence. The heater is switched off automatically after approximately 2 min 30 s.
When the heater sequence is completed the read out of whether or not flames were detected can be made.





Continue - Checking the component and wiring

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Checking the component and wiring








- Ignition off
- Disconnect the connector for the fuel pump.
Check the terminals. Check for contact resistance. Check for loose connections. Check for oxidation.
Check the cable between fuel pump terminal #1 and the combustion preheater module (CPM) terminal #6. Check for an open-circuit.
Check the cable between fuel pump terminal #2 and ground (G53). Check for an open-circuit.
Remedy as necessary.

Other information
- Signal specification Signal Description, Combustion Preheater Module (CPM)
- Component specification [1][2]Auxiliary Cabin Heater
- Fuel pump engine coolant heater, replacing Fuel Pump Engine Coolant Heater, Replacing
- Checking wiring and terminals Checking Wiring and Terminals









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.
- Ignition on.
Activate the heater.
On activation of the heater sequence, the heater starts up and operates for approximately 2 min 30 s. The fuel pump is activated after approximately 45 seconds. There must be a ticking sound from the fuel pump when it is activated.
Do not interrupt the heater sequence. The heater is switched off automatically after approximately 2 min 30 s.
When the heater sequence is completed the read out of whether or not flames were detected can be made.





Does the fuel pump (FP) start?

Yes - Troubleshooting procedure complete

No - 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 the component and wiring

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