blackedoutaudi

To make a long story short, I am trying to figure out a no crank/no start condition.

tjts1

The TCU has nothing to do with no start. Does it crank but not start or no crank? If it cranks the most likely problem is the crank position sensor. And even if the TCU was bad it doesn't need to be coded to the car. That's a lie.

blackedoutaudi

Thank you for the reply.
The car dors not crank over either. The key goes in, all the dash light light up, so my EIS is good.

The dealer could not communicate with the tcu, so they said that can cause a no crank issue. Their diagnosis was bad tcu, bad ecu. After I get the car running they said their is something drawing current that would need to be addressed(found). I also feel I got ripped on the diagnosis. They hooked up their scanner and that was it, but when I made the appointment, they said they will get the car on the lift, check all the wires, ground straps, and currents/voltages. Didn't even get a printout from STAR, just a typed invoice from 1 of the 16 service writers on duty.

My problems are no crank/no start, and when the battery had juice(car sat for a few weeks), the cooling fan says running, which from all my research is a bad ecu, or short somewhere between the fan and ecu. I am a mechanic and can fix almost anything, but I do not had STAR diagnostics so this was out of my reach.

tjts1

It sounds like you know what you're doing. You need your own scanner, look into icarsoft i980 or MB2. These cars really don't like sitting with a dying battery. It can corrupt the memory in the computer modules. It's better to disconnect the battery than let it slowly die.

​​​​ive started my engine with the TCU disconnected so that's not the issue. Check your fuses, check for ATF contamination in your TCU and wiring harness. The fan starts on full blast when there's no communication with the ECU. The signal passes through the front SAM module. The only other coded modules I can think of are the shifter and instrument cluster. With an icatsoft you can connect to each individual computer and see what's what. Good luck.

blackedoutaudi

I know what I'm doing until there's an electrical issue, unfortunately that's my weak suit. I have an Autel md802 all systems, but it didn't help me much in this case, or possibly I don't know what to look for. I'll have to give it another try. The car was sitting with the negative lead disconnected.

blackedoutaudi

To add, the car never did this before, it just wouldn't start one day after I put gas in it, towed it home from the gas station. It did have a code for a throttle position sensor that recently popped up before the issue, but that shouldn't cause no crank/no start.

C230 Sport Coup

To answer your question, just make sure you get the same pn TCU or
an equivalent pn (they are changing all the time)
Different part numbers determine the drive ratio. Somewhere,
I remember reading a thread, someone figured out the part numbers for the different rear end ratios
so people could hot rod their W203's and replace the rear diffs for faster off the line.
But definitely, NO CODING IS REQUIRED for the TCU!
You may need to clear some errors but I would get the iCarsoft 1st before you do anything unless the Autel is just as good.
Anyway, now you know the dealer if full of Sheet, so time to go somewhere else.

Ever had your starter replaced? Do you hear any clicking when you try to start?
Maybe bang on the starter...if it's been sitting and the starter was marginal, I'm sure you know that old trick.

It could still be the EIS despite the lights coming on. If you can read codes etc I wouldn't think it would be the ECU,
as that's where the codes are stored! Dead ECU would mean, you'd never communicate with it via
OBD port. Right? In Mercedes parlance the ECU is the ME, (Motor Electronics).

Did you leave the key in and disconnect the battery?

blackedoutaudi

Never had the starter replaced, tried the banging trick, didn't work.

I was able to connect to the ecu with my autel. It says the same things the dealer tool said, a whole bunch of ecu comm errors and a defective tcu. After pulling some teeth, I was able to get the SDS emailed to me.
It looks like a whole lot a fault codes, ecu related? I don't want to dump a ridiculous amount of money into this, but I'd like to get it running.

Here's the SDS
https://flic.kr/s/aHsmjiY1fG

krazzdav

@blackedoutaudi Whenever I work on cars I clear all codes and reread them. There are only 3 "current" faults (TCU/Sunroof/vent flap) that you read and any of the other things could just be history from a low battery. I recommend first clearing all codes after you do the quick test (it should tell you to turn off the key for a couple seconds then turn it back on), then run the quick test again. This will tell you what the real actual faults are. Your battery voltage is starting to get low also so either put the car on a low amperage charger or freshly charged battery when you do the next test. ~~ you can go down to 11vdc without any issues though.

krazzdav

also you can try typical starter troubleshooting (I never replaced on yet so not sure how it's connected) but have someone turn the key to try and start the car and see if there is voltage going to the starter.

what did this end up being? something drawing current that would need to be addressed(found).

blackedoutaudi

Never fixed the issue yet.

I cleared the codes, disconnected the battery, disconnected the ECU, disconnected the TCU and tried to clean as much oil off the harness as I could. Plugged the ECU & TCU back in, tried to start the car, same thing, no crank/no start.

Read the codes again, and this is what it came up with:
C1038 STORED- Engine control module not identified or incorrect control module.
Event C1024 MIL ON&STORED- CAN communication with the engine system is faulty.
Event C1022 MIL ON&STORED- CAN communication with the engine system is faulty.
Event C1027 STORED- Fault in CAN communication with control unit N1 5/3 (ETC [EGS] control unit).
Event B1036 STORED- The input signal "circuit 61" is not o.k.
B1078 STORED&CURRENT- Fault in communication with component H3/1 (Alarm signal siren with additional battery) or there is a cable fault.

So are we looking at an ECU issue we have here? I'd like to get the ball rolling and fix this car already.

C230 Sport Coup

Is there oil in the ECU harness? Forgive me if I asked this already.
Leaking cam magnets will hose the whole thing.

blackedoutaudi

No oil in the ECU harness.