JNCDD

Hi there! Recent new owner of a 2015 E63 Wagon. Love the car so far, but have been fighting an odd electrical issue and have had no luck after having it looked at by dealer, and doing some digging on my own. Little bit of background, the car is a 2015 E63s wagon. Mostly stock, but has a full exhaust and EC tune. The issue I am having is that randomly (typically only on the highway, and only under moderate to harder acceleration) the car will pop a dash message "collision assist inoperative" and throw the traction control lights on the dash. When this happens, I lose the gas pedal completely and the transmission stays stuck in gear. Only solution is to coast to the shoulder, restart the car, and then continue on as if nothing ever happened.

The codes I am getting seem to be slightly generic. The only one of major concern to me is P263800 - torque reduction requested by trans is rejected by engine control system

The other codes are:
ESP:
C320100 No CAN message received from Engine
C038300 the CAN message received from engine is faulty

SAMF + LIN
B181E2A The signal for the engine hood has a malfunction

AC
911315 - Right footwell vent temp sensor fault - open circuit or short to +

Keyless Go
U100814 - LIN bus 1 has a fault
U100808 - LIN bus 1 has a malfunction - signal fault or message faulty

ABA
U0416FD Chassis CAN Bus no CAN message received from ESP
U0401FD - The CAN message from Motor Electronics is faulty

RFK_C
U014786 - comm with head unit has a malfunction
U016887 - comm with ignition lock has a malfunction the message is missing

530900 - Left front seatbelt tensioner is defective

IRS HRA HLA
U041600 - Implausible data received from traction system

Hoping anyone else here has experienced anything similar and may have any insight.

When it was at the dealership they checked the ME connector and harness and did a pin drag test and all was good. Updated software in all units except ME, to not get rid of the tune.

As far as service history, it appears the car had a new engine wiring harness and ME installed in 2019. The previous owner claims it only did this to him once, and was resolved after a battery change, but my MB tech says the batteries test fine.

Thanks in advance!

täglich

What is ME?

JNCDD

Motor Electronics, AKA the ECU on top of the engine.

PeterUbers

As I was reading and before you mentioned harness was checked and even changed by previous owner I was thinking .. man this screams harness.

presumably his harness was changed because of oil in the harness. Did they change the ecu? Oil in the ecu or ecu damage can do this.

a bad install of the harness? It's a big job to take out and install the harness

Did you tune the car or was it tuned by the prev owner? I've seen tcu tunes do this sort of highway error thing

My first guess is ecu issue once it really warms up and it's faulting, if the wire harness truly is intact and effective.

ALSO - look at your ecu pins again and check for oil.

JNCDD

The harness was changed due to oil in the harness. I have the receipt from when it was done at the dealer in 2019. They did also replace the ECU. The car was tuned two owners ago, after the harness was done and the ECU replaced. No TCU tune as far as I know. I have seen some other instances of the Torque reduction requested code on tuned cars, but no one having issues like this.

I am leaning towards ECU and so is my friend who is a master MB tech. I am just looking for something or some way to be able to get a solid diagnosis before throwing the money at it for a new ECU and new tuning. I own an auto shop, so know my way around electrical diag, but not familiar with these cars.

If it was a bad install of the harness, I would imagine the 2 PO's would have had this issue also. The guy I bought it from states this happened once to him (could be lying) and it was fixed with a battery replacement. The prior owner (who owned the car when the ECU and harness were replaced, and who tuned the car) owned it for almost 3 years after that job was done and said it had never happened to him.

I have inspected the ECU and connectors and there is no oil present.

PeterUbers

i run a used ecu from eBay that has my 100 octane tune and it cost me $200 on eBay and my tuner copier my stock file to it for free. I have four of ecu's, stock, 100, 93, and e40... it's cheap and quick and it'll point you away from a $2500 brand new Benz acquired ecu if the issue recurs.

change the battery anyways - read plenty of times that battery load tests fine then gets replaced and electrical gremlins go away

agreed that previous owner who is incentivized to dump the car and doesn't want drama with you now is potentially lying.

my buddy had a similar issue with his Range Rover once .. the car would essentially stall randomly but mostly with hard momentum like pulls or dig acceleration.... it was a totally normal OEM factory installed wire harness with a loose pin/plug that was so subtle that just before they lemoned the car the dang master tech found it and fixed it ... he was stuck with the car and all its bad memories. Car drove fine after

when the engine was under heavy load like acceleration, it would twist on the motor mounts and twist just enough to tug on that defective wire harness connector to pull the pin away and cause the fault

JNCDD

Maybe I will try a used ECU first then... Not a bad idea. Probably going to have to at least buy a new tune though since I did not originally tune the car.

Totally agree on the previous owner not wanting to admit it. Is what it is, I bought the car right, and know how it goes with older german cars. Didn't expect it to not have its fair share of issues.

Do both batteries need changed do you think?

I am not sold on it being a pinched harness or a loose pin, because its not easily repeatable. It will go weeks without doing it, and then do it twice consecutively. Has happened under light throttle, moderate throttle, heavy throttle, but has not acted up doing the same pulls, or drives before and after the fact. It really is random.

PeterUbers

in for a penny in for a pound - change the aux batt too

Random electrical gremlins are likely one of the top reasons to dump a German car in modern times. And thanks to the random nature they run fine in the used car lot and a sucker takes it home. There is just no great algorithm to tear through to solve it since there is no great heuristic.

its most likely you'll never solve this, statistically that is. And I do want you to solve it because I want you to enjoy this awesome car. The cheapest way out of this car may be sticking a for sale sign on it right now. Seems unsafe at the moment since it's random and that makes it more challenging.

have you checked your ground points? Bad grounds in German cars is a thing, @CaliBenzDriver will speak about that at times.

JNCDD

My next step beyond changing both batteries was going to be to try a new ECU and tune and see if that fixes it. I had thought about pulling up the diagrams and checking all of the ground points. I am familiar with bad grounds causing ghost issues. I'd rather not sell the car right now, especially don't want to pass the problem onto someone else. This car was a nice change of pace for me! I have a few BMWs, but this is my first MB. Always wanted an E63 wagon. I am determined to get to the bottom of this one way or another!

PeterUbers

you're an honorable man

täglich

On an unrelated note, we would all love to see photos of your new (to you) wagon.

CaliBenzDriver

Good job on your survey. You have a fully grown CAN-C disruption that limp-modes dangerously on the highway.


Normally this money-pit would get stuck on a used car lot without fix... we can turn that around with your help.

The big question we need to discover for your chassis is what's the active trigger?

The outcome we know from the active faults is soft-crashed CAN-C (ESP + ECU + TCU). ​​​​​

I am surprised the ISM is not complaining at all... this makes it one of the possible suspect as disruptor!

> LAYERED CHAOS:
MB uses a sure-kill approach by providing multiple unfavorable conditions.
This thread is an extreme case of the solderless ESP/ISM that disables everyone's GDI timings and out of sync TCU with confused reactions. Here it bugs the timely collaboration of [ECU <--> TCU] into quitting.

-- What are the layers :
unstable CGW firmware transactions flood
painted GND posts shared with glitching by high loads
Single Main GND Strap exposed undercarriage
ALT voltage yoyo drains batts below 12.1V
flooded footwell oxidized connections


> SHORT-TERM: relief the consequences

> LONG-TERM : focus on the causes.

....//...

PeterUbers

Did it ever happen with cruise control on?

do you have a valentine or radar detector hardwired where they needed to tap into the headliner or overhead area by the distronic cameras?