Signal Missing
Signal missing
Checking the function of the climate control module (CCM)
- Ignition on.
Check the power supply to the climate control module (CCM) by switching on the climate control system.
The blower fan must blow and it must be possible to regulate the fan speed.
Does the blower fan blow?
Yes - Checking communication with the climate control module (CCM)
No - Checking the power supply and ground for the climate control module (CCM)
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Checking communication with the climate control module (CCM)
Hint: The CAN communication with the control module is OK if the control module ID can be read off. In that case the fault is probably intermittent and will then be more difficult to trace.
- Try to communicate with the climate control module (CCM) by reading off the control module ID
- Click on the symbol for VCT2000 to begin reading off
Continue - Signal missing
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Checking the power supply and ground for the climate control module (CCM)
- Ignition off
Check fuses in the engine compartment fusebox for the power supply to the central electronic module (CEM).
Check the fuse in the central electronic module (CEM) for the infotainment supply relay. The relay is inside the central electronic module (CEM). If the fuse is blown, check the circuit by the central electronic module (CEM) before replacing the fuse. Check for a short-circuit to ground. Then replace the fuse.
If necessary, check the cable from the junction between the supply cable for the infotainment control module (ICM) and the supply cable powering the climate control module (CCM). Check for an open-circuit. Check for a short-circuit to ground.
Check the ground cable between the climate control module (CCM) and the ground terminal. Check for an open-circuit. Also check the ground terminal. Check for contact resistance and oxidation.
Remedy as necessary.
Other information
- Connecting the breakout box Connecting the Breakout Box, Central Electronic Module (CEM)
- Checking wiring and terminals Checking Wiring and Terminals
Was a fault detected?
Yes - Verification
No - Checking the Infotainment relay status
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Checking the Infotainment relay status
Hint: If the power supply to the climate control module (CCM) does not function, this can be due to the Infotainment relay in the central electronic module (CEM) not functioning.
- Ignition on.
Check the status and activation of the Infotainment relay. Click the VCT2000 symbol.
There is an internal fault in the central electronic module (CEM) if the relay is not activated and cannot be activated. In this case, the central electronic module (CEM) must be replaced.
Other information
Was a fault detected?
Yes - Verification
No - Signal missing
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Signal missing
No Fault Found - No Fault Found
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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.
Check the power supply to the control module by switching on the climate control module (CCM).
The blower fan must blow and it must be possible to regulate the fan speed.
Does the blower fan start?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFIED - FAULT FOUND
VERIFICATION FAILED - Fault-tracing information
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Fault-tracing information
Attempt New Test - Checking the function of the climate control module (CCM)
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