Bogleg

The instrument cluster on my 2001 C240 appears to have died, but I want to make sure the problem isn't elsewhere before dropping $$-$$$$ on parts. I believe it has about 125K miles on it, but I can't tell right now.

My wife was driving on the highway, and she heard several (4-5) beeps, and then the cluster just shutdown. The car remained running and responsive (except for the cluster) for the rest of the drive home (about 5mi).

I have a cable and software from ross-tech.com that I got years ago for my '99 Jetta (the HEX-USB cable without CAN support), but no other OBDII gear. It's good enough to pull codes from my C240. The only code present is P0600. I can read the engine speed and all sorts of other stuff from OBDII without problems.

I don't have anything fancy for diagnosing the CAN, but I poked at CAN-B with my multimeter, and the voltages look fine at a glance - H = ~0.6V awake, ~0.02V asleep; L = ~4.6V awake, ~11.5V asleep.

I replaced the battery when it died (with all the crazy symptoms that come with that) about 6 months ago. It appears to still be in good health, and I could not find any blown fuses.

I disassembled the IC, and there's no visible damage. The blue high-beam indicator LEDs do work, and the amber LEDs that backlight the LCD also work. The blue LEDs blink slowly when the car is asleep, and they stay lit when it's awake. The amber LEDs are asleep with the car, and light up when the car wakes up (not sure if they stay that way -- TODO: figure out when). I am running with no LCD screen or speedometer needle right now.

NOT WORKING:

• Instrument Cluster:
  • Gauges (tachometer stuck at ~2550rpm, speedometer stuck at 61mph, fuel gauge stuck just above empty)
  • LCD only barely flickers occasionally, with no discernible text on it (when waking the car up, maybe -- right now it's removed)
  • All idiot lights
  • All the noises from the cluster speaker
• Steering wheel buttons (can only really test them as radio volume controls without a working LCD)
• Windshield wipers

PARTIALLY WORKING:

• The radio works, but the steering wheel buttons don't adjust volume anymore
• The door locks work, but they don't auto-lock when I reach the speed threshold (~8mph?)
• With headlights in 'auto', high beams will not switch on by pushing the switch forward, but pulling the switch back to flash the high+low does work. With headlights 'on', pushing the switch forward does turn on high beams.
• Turn signals work, but they're inaudible.

WORKING:

• Normal driving functions
• A/C
• Ignition
• Key-fob door lock/unlock/trunk-open
• Key-fob open and close windows + sunroof
• Windows
• Cruise control
• 12v outlet
• Seat adjustment
• Side-view mirror adjustment
• All lights (interior and exterior) as far as I can tell

I tend to DIY pretty much everything. Do any of you have any clues as to what else this might be, or what else I can look at?

Thanks for all the clues that I've already pulled from this forum, by the way. There's loads of good information here and on the wiki page.

benzmodz

This is a collapse of your canbus network. One of the modules is pulling can down.

Active canbus is +9V H and -9V L which gives 18V.

I'm pretty certain your cruise won't work either. Time to start disconnecting modules. Check for water damage.

Your car will run without a cluster.

Bogleg

I tested cruise control on the way home from work, and it did work. I was surprised.

Where did you get +9/-9/18V? I haven't seen those. Are you talking about CAN C? I haven't looked at that yet, or the ignition switch.

benzmodz

Both rails of the CAN B should be the same voltage but opposite polarity. The fact that cruise works confirms that CAN C is operating normally. It also means that your clock spring isnt totally broken.

Bogleg

Is this supposed to be some kind of joke or something?

Did you have something to do with the Rangers collapse this past couple of weeks, too?

EDIT: Sorry, frustrated baseball fan here. What's your source for this CAN information? It goes against everything I've read and seen.

benzmodz

Canbus is a differential network. My source is Mercedes diagnostic, WIS and Vector GmbH.

Given your canbus has gone nuts you might want to take readings from a friend's car.

Unused CAN is high. In other words, the highest reading means nothing is being sent down the line. As traffic increases the voltage is closer to zero. Not to be confused with sleeping canbus.

Bogleg

I understand that CAN-H gets a "0" when CAN-L gets a "1", and vice versa, for redundancy. I just don't see where you are getting +/- 9V (for 18V total? Besides the fact that -9 + +9 = 0, not 18, it's a 12V system).

Both rails are positively charged as they should be, according to everything I've read prior to this thread.

I have been digging through WIS, and I can't find where it specifies the voltage on either CAN bus (B or C). The numbers I have found are from various threads on this forum and a PDF on the MBWorld wiki:

https://mbworld.org/forums/c-class-w...es-broken.html

(from https://mbworld.org/wiki/index.php/W203 - "CAN Networks"):
http://static.ibsrv.net/mbworld/Can%...2010-28-02.pdf

Seriously, though, thanks for any help you can provide. I will go digging further for possible water damage or shorts.

benzmodz

-9 + 9 = 0 ?????

Potential difference ..... Maybe read that first.

Bogleg

OK, I get that, but that still doesn't explain why you're using those numbers instead of the 0.25/0.6 H, 11/4.5 L.

Bogleg

More digging and prodding. Added key-fob window down&up to the WORKING list. All the lights including the makeup mirror lights work as well. It's behaving a little bit differently now. The high beam indicator now does a quick 4-6 blinks (variable, usually 5), then a pause for a second or two, then repeats. This is after turning off the ignition. Also, now it beeps once when I turn off the ignition.

With everything else working like it is, I am starting to think the IC is just toast.

Bogleg

I don't know why I hadn't thought to try them before, but the windshield wipers don't work at all, including the washer spray. Added to the NOT WORKING list in the OP.

Since my last post, I got a few new toys from Amazon.

I ordered a "ELM327 CAN-USB" cable, but it's a cheap knock-off that doesn't work properly with any software. It's going back today for a refund because it's not what I ordered -- ELM's website says there is no ELM327 v1.5, yet that's what this thing claims to be.

I also ordered a Carsoft 7.4 mux, and I got that working yesterday. I ran through all the components that it found (the cluster was not one of them!), and cleared the codes that were there after recognizing that the vast majority were from me unplugging things from the CAN-B Bus. Then I started the car and ran another full diag that came back full of errors again. I didn't get to every component (takes forever), but all of the ones I checked said they were unable to communicate with the instrument cluster.

So, regardless of our above voltage debate, I don't think the CAN has collapsed; everything else still seems to be able to communicate just fine.

What are all my options?

Does anyone here have experience with actually repairing a cluster (besides the LCD replacement)?

I saw in a thread here somewhere that said it's possible to code used ICs with mileage so it'll be in sync with an ignition switch. I will look for that thread again, but if anyone has direct knowledge there, that would likely help me if I can find a cheap used cluster.

If I do have to get a new one, can I do the install / coding myself (w/o Star DAS)? What would that take?

Bogleg

I dropped $100 on an old cluster from ebay, even though I knew it would not show my odometer mileage. I used CS74 to clear all the errors, and they haven't returned. Glad to have a speedometer and fuel gauge again.

I have done more searching, and it seems these are my options:

1. Replace it with an expensive new one ($$$ - $$$$)
2. Buy ENIGMA and program it myself ($$$ - $$$$)
3. Find someone to program the right mileage into it ($$ - $$$)
4. Send it to Palo Alto Speedometer to have them erase the EEPROM so that it appears new which would cause it to adopt the mileage from the EIS (?)
5. Send it to BBA Reman to have them rebuild it ($$$)
6. Find someone else to erase the EEPROM (?)
7. Figure out how to erase the EEPROM myself

If anyone has any other options or clues for a DIY fix, I'd really appreciate it.

skonski

This exact problem has happened to my 2003 C240, what did you end up doing?

We're debating between buying a used one and dealing with no milage $50-160 or getting a new one and having dealer reprogram $1460...

Bogleg

I am still running with no odometer. I have not had any other related problems, and the car still passes inspection w/o odometer. I don't think I'll have a problem until I try to sell it.

I do wonder if the ignition switch is still counting the miles. If I erase the EEPROM, will I get the true mileage, or the mileage that the ignition switch knew about before the IC died.

eric tk wong

Hi. I have the same situation like your vehicle. The cluster suddenly dead. Have you solved your problem. May be you can advice me. Many thanks

Peter Maldonado

hey did you resolve your problem cause I got the same problem

Peter Maldonado

?

Russell Ormerod

@benzmodz
Sorry but you talk absolute BS regarding can bus function and voltage levels, other than confuse people here!

As far as cluster is concerned you Need to remove eeprom and make the km 0 then with Das you can learn the SSID and the km will transfer from the EIS.