marc hanna

As the title says, I me electronic module for the ESP/ABS is bad.
2005 C240 4matic
codes:
C1101
C1142
C1124
C1102
C1121
2401
2403
2430

Of codes are cleared car will drive okay for a little while. Then it stops shifting.

Already replaced the conductor place and receptacle. No apparently leaking in the front SAM

Thoughts?

slammer111

I assume you're talking about the TCU module underneath the passenger side footwell? That is the module that acts up when the pilot bushing (I assume what you're calling the receptacle) leaks up the wiring.

marc hanna

No, I haven’t looked there yet. The codes seemed more associated with the ESP control module. I’ll check the TCU out though.

slammer111

A malfunction in the TCU will cause rough shifting. I imagine the ABS module won't.

Just feel the wire coming out of the transmission. Mine was just soaked in oil throughout the entire length. Be sure to update the pilot bushing if it hasn't been done so already. There are 3 versions in total, and the older 2 versions are pretty much guaranteed to leak. If nobody has looked into this problem on your car you'll want to remove and clean the TCU as well.

marc hanna

The wiring harness was dry on the outside, and only a small amount of oil had breeched the o-ring. So, I really didn’t think of investigating the wiring harness any further, especially because it worked fine for about a week.

marc hanna

Well, I pulled the TCM and it definitely has oil wicked up all the way to the connector. Currently in the process of giving it a good cleaning.

Any experience with the TCM still working afterwards? Or are these normally cooked after this happenx?

marc hanna

No sign of oil ingress inside the TCM. So, hopefully no damage there.

marc hanna

Well, that didn’t work.

slammer111

To be sure, hose down the TCU PCB with some electrical contact cleaner. In any case, looks like you need at least a new pilot bushing.

When you say "stopped shifting", is the car stuck in a gear, or is it dropping into N?

marc hanna

That’s all been done already. As mentioned previously, I replaced the conductor plate and the pilot bushing (which is known by many names) and that solved the problem for about a week and a half. Today, I removed the TCM and opened it up, it was clean and dry inside but I cleaned it withe electrical contact cleaner anyways. I also disassembled the plugs that go into the TCM and cleaned them well. And finally I cleaned all the wiring harness as well.

The symptoms I am experiencing are this:
1. After all codes are cleared, car initially starts and drives fine. Shifts also.

2. Upon stopping the first time, it noticeably downshifts hard.

3. After that it will only work in 1st gear when in ‘drive’ and reverse and neutral work fine.

4. Manually tipping the shifter to manually shift through the gears does nothing.

slammer111

Just throwing it out there. Have you checked the transmission fluid level, and is the fluid the correct approved stuff?

How's the battery condition? The car is known for doing a lot of weird stuff when the voltages are incorrect.

I would also look into the voltage regulator if that hasn't been changed out before. When mine went bad, it caused some very rough shifting. My error was different though. The VRs are known to occasionally go bad, at least on the earlier builds.

marc hanna

Transmission fluid is good.

Alternator is new, but I will double check the running voltage.

marc hanna

Well, I pulled the ABS control module off. No obvious issues and no corroded terminals, but the unit is sealed and I don’t think I can open it without breaking it.

anyways, I put it back on and cleared the codes. Now the car is driving and shifting fine with the exception of a hard downshift as i’m coming to a stop.

slammer111

Sounds like the TCU cleaning did something. Maybe try cleaning it again?

The TCU also had a firmware update for the older cars. Not sure if it applies to yours. Might want to touch base with the dealer.

Just to confirm. You've checked the transmission fluid level? These cars are very unforgiving with incorrect levels in either direction.

marc hanna

On the contrary, I think it is the ABS control unit. After cleaning the TCM there was no change, but after I pulled the ABS module and reinstalled, the issue was resolved.

Yes, TF is spot on.

The only fault I’m still getting is the one regarding the N47-5. So, I’m pretty sure I’ve zero’d in on it.

I’m going to take a closer look at it and inspect the pins closely. These modules are pretty expensive, so I want to salvage it if I can.

slammer111

Interesting problem. Haven't seen this one before but looks like it happens on other models as well.

If you're able to locate the problem, please post the fix as well. Good luck.

marc hanna

There are any number of components that can interrupt the speed signal. Any of these can affect the others. The weirdest one I came across was the the rear signal lights on an 2002 ML320, a little too much draw will affect the ESP. But another one that affects the shifting is the stop light switch and pedal mounted versions.