Signal Too High / Signal Missing

Signal too high / Signal missing

Checking the function of the flame sensor




- Ignition on.
Activate the glow plug.
Read off temperature at the flame sensor by clicking on the VCT2000 symbol. The temperature must rise after activating the glow plug.

Caution! Do not activate the glow plug for more than 10-20 seconds.

If the temperature does not rise after activating the glow plug, this is an indication that the fault is permanent.
If the temperature rises after activating the glow plug, this is an indication that the fault was present previously but that it is not active at the moment, i.e. an intermittent fault.





Continue - Checking the component and wiring

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Checking the component and wiring








- Ignition off
- Disconnect the connector for the flame sensor.
Check the terminals. Check for contact resistance. Check for loose connections. Check for oxidation.
Check the cable between control module terminal #1 and the flame sensor terminal. Check for an open-circuit. Check for a short-circuit to supply voltage.
Check the cable between control module terminal #2 and the flame sensor terminal. Check for an open-circuit. Check for a short-circuit to supply voltage.
Remedy as necessary.

Other information
- Component specification [1][2]Auxiliary Cabin Heater
- Signal specification Signal Description, Combustion Preheater Module (CPM)
- Flame sensor engine coolant heater, replacing Flame Sensor 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 glow plug.
Read off temperature at the flame sensor by clicking on the VCT2000 symbol. The temperature must rise after activating the glow plug.

Caution! Do not activate the glow plug for more than 10-20 seconds.





Does the temperature rise at the flame sensor?

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 function of the flame sensor

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