Checking Display
Checking the display
Fault-tracing information
The MOST network is a fiber optic ring network. This means that all control modules which are connected to the network must be powered and grounded for the infotainment system to work. If, for any reason, a control module is unable to transmit the signals onwards on the MOST network, or if there is an open-circuit in the fiber optic cable, the infotainment control module (ICM) will shut down all functionality.
Communication on the fiber optic net is one-directional. The control modules on the MOST network receive light signals, amplify them and then send them onwards. The MOST connectors for the control modules contain two fiber optic cables, one for incoming and one for outgoing signals. The cables must be correctly positioned in the connector for communication to function.
Faults in the infotainment system may result in the display on the infotainment control module (ICM) flashing or not being lit when the infotainment control module (ICM) is activated.
The fault can be both permanent and intermittent.
The fault causes may be:
- Open-circuit or loose connections in the wiring between the display and the infotainment control module (ICM)
- A control module other than the infotainment control module (ICM) is interfering with the communication on the MOST network
- Problem downloading the correct software
- Damaged display.
- Damaged lift motor.
Note! The infotainment control module (ICM) stores a diagnostic trouble code (DTC) if the display voltage is incorrect. The display also switches off if the MOST network is not functioning or if there are internal faults in the infotainment control module (ICM). If there are diagnostic trouble codes (DTCs) in the infotainment control module (ICM), these must be fault-traced first.
Continue - Checking the component
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Checking the component
- Ignition on.
Check whether the fault is in the infotainment control module (ICM) as follows:
- press the POWER button twice with a couple of seconds in-between
- press the MENU button.
If a menu text is now displayed, the fault is not in the infotainment control module (ICM) but in another control module on the MOST network.
If no menu text is displayed, continue fault-tracing the infotainment control module (ICM) as follows.
Checking the infotainment control module (ICM)
A test of the display can be run by clicking the VCT2000 symbol.
Remedy as necessary.
Other information
- Information and Entertainment Display Service and Repair
Was a fault detected?
Yes - Verification
No - Checking components
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Checking components
Check the functionality of the MOST network by first checking the CD player and then the radio reception.
CD player
Check the functionality of the CD player as follows:
1. Select the CD player by pressing the CD button
2. Check that the display shows that CD has been selected
3. Play a CD. Check that there is sound from the loudspeakers. Do not use copied CDs during this check.
Radio reception
Check the functionality of the AM/FM tuner module (AFM) as follows:
1. Select radio reception by pressing the AM/FM button and switching between FM1, FM2 and AM
2. Check that the display shows that radio has been selected
3. Check that there is radio sound from the loudspeakers.
To continue fault-tracing, select from the following alternatives.
Alternative 1:
No sound in the loudspeakers when playing a CD.
Alternative 2:
No sound in the loudspeakers when playing the radio.
Alternative 3:
No sound from the loudspeakers for the CD or radio.
Select an alternative.
1 - Checking the CD player
2 - Checking the AM/FM tuner module (AFM)
3 - Checking MOST communication
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Checking the CD player
Check the power supply and ground terminal for the CD player. Check for an intermittent open-circuit. Check for an intermittent short-circuit to ground. Check for an intermittent short-circuit to supply voltage.
Remedy as necessary.
Other information
- General audio player module General Audio Player Module
Continue - Verification
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Checking the AM/FM tuner module (AFM)
Check the power supply and ground terminal for the AM/FM tuner module (AFM). Check for an intermittent open-circuit. Check for an intermittent short-circuit to ground. Check for an intermittent short-circuit to supply voltage.
Remedy as necessary.
Other information
- AM/FM tuner module (AFM), replacing Radio Control Module
Continue - Verification
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Checking MOST communication
Check the communication on the MOST network by bypassing the control modules one by one on the MOST network as follows:
- Ignition off
- Disconnect the MOST connector from the relevant control module
- Connect the MOST cable to special tool 951 2867 MOST instrumentation 951 2867 MOST Instrumentation
- Ignition on
- Activate the infotainment system
- Check that the communication on the MOST network is functioning by reading off the status of the MOST locked parameter for at least 30 seconds. The parameter indicates whether the MOST network is closed and communication possible.
Click the VCT2000 symbol to read off the status of the MOST network.
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 infotainment control module (ICM) by pressing the POWER button.
Check that the display lights.
Check that the sound source can be selected and that playback is working.
Is the infotainment control module (ICM) working?
Yes - VERIFIED
No - VERIFICATION FAILED
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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 - Exit fault-tracing
No - Attempt New Test
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FAULT-TRACING FAILED - FAULT-TRACING FAILED
Attempt New Test - Checking the component
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