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P1747 MERCEDES-BENZ - Electronic Gear Selector Module: Defective Interaction of CAN With Control Unit Instrument Cluster
This current fault code is set on my vehicle. I had it two years ago but it cleared itself. Is this fault code related to an instrument cluster issue or a gear selector/transmission issue? CAN is a network? My instrument cluster behaves erratically—flashes lights, freezes, doesn’t work at all, or works normally. I have no shifter/transmission problems.
Is the domelight on the same curcuit as the instrument cluster?
If the IC has the electronic odometer, doesn't the replacement IC need to be "virginized" and then programmed with a Star system so the the odometer reads correctly?
If so, it might make more sense to send the existing cluster to a good electronic speedo repair shop and see if they can repair it first.
Last edited by Floobydust; Aug 21, 2020 at 08:54 AM.
I believe that when there is a mis-match between the mileage in the ECU and that in the IC, the odometer displays "- - - - - - - -". That would cause an issue with the annual inspection here. I'm not sure what the issues might be with the CA biannual emissions inspection might be.
This compatibility/replacement is typical of the MBZ mismanagement of the entire electronics SYSTEM. I contrast their problem plagued electronics/electrical systems with those of Toyota-Lexus and Nissan-Infiniti----which are typically trouble-free.
I do not know the root cause for the very troublesome software/hardware systems--I just note the PERFORMANCE and long term reliability (and replacement parts prices and availability,) are very poor and similar to those of BMW's. Hopefully the new Chinese Owners of Volvo can 'show the way' to doing it right.
How can it be tolerated to be unable to supply replacement ignition key assemblies???? This is akin to the failed French effort to build the Panama Canal 150 years ago.
The MBZ SL instrument cluster failures are usually caused by failing electrolytic capacitors. The same mode of failure is very common in German electronic assemblies starting in the early 90's and some Japanese auto electronics (amplifiers, BOSE Speakers, etc) Apparently these small and inexpensive electrolytic capacitors are not able to survive the higher temperatures and loads encountered in modern automobiles. For example, in my 1994 SL-600, the 7 channel BOSE system sounds exquisite now ALL the electrolytic capacitors in ALL the speaker amplifiers, tuner, main amplifier, woofer amplifier have been replaced. BOSE was very understanding and supplied gratis new, higher rated capacitors, and even replaced free the driver's door main speaker with its housing (NLA from Mercedes) when the speaker surround rotted away.
Yes, there is an issue with the electrolyte that was used in electrolytic capacitors from that era drying out and/or causing corrosion and then failing. As you mentioned, it not only affects automotive electronics, but consumer electronics as well. I have replaced many a capacitor over time. In my experience, the problem seems to be worse for capacitors/equipment made outside of Japan.
Mercedes has been particularly egregious about killing off support for the older platforms. The been counters rather then the engineers are in charge there now. All they want to do nowadays is sell you a new lease.
It's great the Bose was so accommodating! One of my door drivers is out too, so I will have to check with them.
Last edited by Floobydust; Aug 21, 2020 at 12:15 PM.
concerning replacing the 3 capacitors likely to fail in these units. That may not solve my code problem, but it will evidently correct the intermittent flashing and flickering lights. I plan to replace the capacitors on mine prior to buying a used unit. I am taking the car to the local indie MB shop to get an official reading of the code.
The used units with the digital odometers seem to retain the mileage of the source vehicle. As long as the mileage is higher than the last smog check, it should pose no problems.
If I have anything to do with it, my 23-year old (rust-free) “bucket” will not end up in a scrap yard anytime soon.
I still suggest that you have your original IC repaired by a reputable shop if you plan to keep your call for the long term. The shop should replace the bulbs as part of the repair (make sure they do). If you go the salvage yard route, then yes, replace them while it is out.
i will probably do that. i removed the IC from of the dashboard (with relatively little trouble) but nothing is visibly wrong with it so clearly someone with the right testing equipment has to look at it.
I forgot to mention that when I removed the IC, I found (2) cut wires, one green, one black, at the far left side of the recess (see photo). They do not appear to have been cut from either IC connector. Besides those 2 connectors, are there any other electrical connections to the IC? Anyone know what these are for?
Severed wires behind IC
Also, the outside temperature does not display on the lower field of the odometer LCD.
The P1747 code mentions the IC, the shifter module, and the CAN bus. Is it true that disconnecting the negative battery cable for a few seconds will reset the CAN? Does this code mean the ECU has lost communication with the transmission? I recently replaced the plastic connector sleeve of the electrical connector to the transmission. Could the lack of communication with the CAN be caused by a prohlem with the connector? I have no shifting or transmission issues.
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