Hi,
Looking for info and help... Was driving for 10 min stoped at a traffic light.. was driving in comfort "C"
Traffic light turned green and car did not move. The engine was revving up and not moving. Car shut down with dash saying "do not drive" ( something like that ) or damage to gears Transmission (see dealer for services) the car would not start and would not come out of park "P" Great...so tow truck.....some dawn dish soap and water and slid it on to a flat bed.

code U028 Vehicle Communication Bus 'A' took it back to shop and disconnected both batteries. I did search the forum on code U0028 not much info. New here to the forum.. any info or help would be appreciated... Regards, Matt

 

It was a plastic electrical clip connection on Transmission broke, disconnected and melted to the exhaust. $7.00 from the dealership.

 

That was quite the "Phew" moment I bet!

 

did the car start when u had this issue and any other errors ?? As my car had the error and switched off engine and now intermittently starts but does not change gears and garages are unable to figure it out? Multiple faults errors showing all warning lights too.

 

did you check for oil in the engine wire harness?

 

the car is in the garage and they said it’s come back with over 100 faults. All visible wiring checked. Was driving and all of a sudden car error came up with our changing fears consult workshop. And then pulled up on side turned off car and then would not start up at all and does not change gears, will ask garage if checked wiring harness but I believe they have thank you..

here are some faults from rac breakdown

The errors from rac breakdown report was





System Type: ENGINE SYSTEM TEST/VALUES

Name: 651.921 - CRD3S2

DTC: U0028,Vehicle Communication Bus A

DTC: P0627,Fuel pump output; electrical fault or open circuit DTC: U0155, No communication with instrument cluster DTC: U0122,CAN: communication fault with TCS (Traction Control System)

DTC: U0111, Battery management system, communication faulty

DTC: U0212, Fault in CAN communication with steering column module

DTC: U0115,Communication with drivetrain control unit

DTC: U0128,CAN; communication fault with electromechanical parking brake controller

DTC: U0164,Communication with climate control system

DTC: U0168,CAN: No reception of EZS (electronic ignition)



System Type: GEARBOX

Name: GEAR SELECTOR - GEAR SELECTOR (INTELLIGENT

SELECTOR MODULE)

DTC: P1240,CAN bus malfunction

DTC: U0121,CAN: communication fault with ESP (Electronic Stability Program)

DTC: U0101,Communication fault with control unit automatic transmission

DTC: U0168, Control unit EZS is faulty

DTC: U113B,CAN communication with Direct select control unit, faulty



DTC: U0155, No or incorrect message from IC (Instrument

Cluster)

DTC: U0111, No communikation with battery control module

DTC: U0128,Electric Parking Brake

DTC: P179D,Emergency mode for “Direct Select” was activated

DTC: U0146, Central gateway control module; implausible signal

DTC: U0415, Invalid data received from ABS control module

DTC: P179A, Redundancy system for DIRECT SELECT

System Type: GEARBOX

Name: GEARBOX - GEARBOX

DTC: U0141,Communication with the front signal acquisition and actuation module has a malfunction.

DTC: U0100,Engine control unit; communication faulty

DTC: U0002, Powertrain CAN bus off

DTC: U0121,CAN: communication fault with ESP (Electronic

Stability Program)

DTC: U0146, Fault in CAN communication with central gateway

DTC: U0001,CAN bus off

DTC: U0126, No CAN message was received from control unit steering column module

DTC: U0426,DAS (Drive Authorization System), has not sent message to enable engine start

DTC: U0028,Ignore fault code and erease fault memory



System Type: WHEEL SYSTEM

Name: TIRE PRESSURE MONITORING SYSTEM - TYRE

PRESSURE MONITORING (TPM 222)

DTC: U0100,Engine control unit; communication faulty

System Type: STEERING

Name: ELECTRICAL POWER STEERING - ELECTRICAL

POWER STEERING (EPS205_TK / EPS205_ZF)

DTC: U0101,Communication fault with control unit automatic transmission

DTC: U0100,Communication with the engine control unit

DTC: U0402,CAN communication from transmisson is invalid or implausible

DTC: B210F,Terminal 30

System Type: IMMOBILISER

Name: IMMOBILISER - EIS222

DTC: U1198,Communication fault with control unit Intelligent

Servo Modul

System Type: AIRBAG ELECTRONICS (SRS)

Name: AIRBAG - AIRBAG (ORC222)

DTC: U0100,Communication with the engine control unit



System Type: CENTRAL ELECTRONIC UNIT

Name: SIGNAL ACQUISITION AND CONTROL MODULE - FRONT - SIGNAL ACQUISITION AND CONTROL MODULE



System Type: AC SYSTEM

Name: CLIMATE CONTROL - CLIMATE CONTROL (HVAC222)

DTC: U0100,Communication with the engine control unit

System Type: STEERING WHEEL ELECTRONICS

Name: STEERING WHEEL ELECTRONICS - STEERING

COLUMN MODULE (SCCM222)

DTC: U010087,Communication with the engine control unit

DTC: U010187,Communication fault with control unit automatic transmission

System Type: LIGHTING SYSTEM

Name: HEADLIGHTS - CURVE LIGHT, LEFT - HLIFL_222 - MT/ AT

DTC: U0100,Communication with the engine control unit

DTC: U0168,Control unit EZS is faulty

System Type: INSTRUMENT PANEL

Name: INSTRUMENT - INSTRUMENT (IC)

DTC: U0100,CAN communication with the engine system is faulty

DTC: U0101, Gearbox control unit communication fault

DTC: U0109,No or incorrect CAN message from control unit

Fuel pump control module

System Type: DRIVER ASSISTANCE SYSTEM

Name: PARKING ASSISTANCE - PARKING



System Type: DRIVER ASSISTANCE SYSTEM

Name: PARKING ASSISTANCE - PARKING ASSISTANCE (PTS222)

DTC: U0100,Communication with the engine control unit

DTC: U0101,Communication fault with control unit automatic transmission

System Type: ENGINE

Name: EOBD

DTC: U0028,Vehicle area network (VAN) data bus A DTC: P0627,Fuel pump (FP) control - open circuit

DTC: U0122, Data bus, vehicle dynamics control module - no communication

DTC: U0111, Data bus, battery energy control module A - no communication

DTC: U0115,Data bus, engine control module (ECM) B - no communication

System Type: BRAKES

Name: ESP AND ELECTRIC PARKING BRAKE - ESP AND ELECTRIC PARKING BRAKE (ESP205 / ESP205_AMG)

DTC: U0404, Implausible data were received from the electronic selector lever module.

DTC: P1644, Faulty variant coding

DTC: U0402, Implausible data were received from control unit

‘Transmission’.

DTC: U0100,CAN: communication engine

DTC: U0101,Lost Communication with transmission control



DTC: U0404,Implausible data were received from the electronic selector lever module.

DTC: P1644, Faulty variant coding

DTC: U0402,Implausible data were received from control unit

‘Transmission’.

DTC: U0100,CAN: communication engine

DTC: U0101,Lost Communication with transmission control module

DTC: U0401,Implausible data were received from control unit combustion engine.

System Type: INSTRUMENT PANEL

Name: OVERHEAD CONTROL PANEL - PANORAMIC

SLIDING SUNROOF CONTROL UNIT (PANORAMIC SLIDING SUNROOF)

DTC: U0168,CAN: fault message from EIS (Electronic Ignition System)

System Type: DRIVER ASSISTANCE SYSTEM

Name: ACTIVE BRAKE ASSIST - ACTIVE BRAKE ASSIST (FCW) DTC: U0100,Communication with the engine control unit

DTC: U0401, Implausible data were received from control unit combustion engine.

DTC: U0416, Implausible data were received from control unit

“Traction system”

DTC: C10C8,Warning from the control unit COLLISION PREVENTION ASSIST



U002888

Communication with the drivetrain CAN bus has a malfunction.Bus OFF

CURRENT and STORED

Freeze Frame

Code Search

Data Stream

 

Has the main battery outright been replaced - it should even if load testing was ok - these cars are so electrically sensitive

also a rodent could have chewed through inaccessible harness section.

water damage - any wet spots near windows... follow gravity and see if a harness got wet on interior

 

main battery was changed and replaced still same issue , garages have given up with my car been sitting there for two months. And no one Leicester wants to even touch this car with this issue. And now am stuck clueless what to do,
and Merc will charge arm and a leg for this no doubt.

 

is it worth asking if your insurance company can total it - perhaps it was in a flood 😉 or what a shame you left the sunroof open in that thunderstorm

I'm kidding of course

 

@CaliBenzDriver what do you think - this screams harness or water damage to me ... bad ground somewhere?

 

Yes Peter: high chances for water intrusion into SAM's private tub.

I read through the report from basic scanner.
​​​​​It reads like the whole CAN-C is disrupted but still chatting as ECU/TCU/ESP/ISM did submit their faults. Meaning the bus is up but worst than single-wire mode....

All faults are concentrated right there.
No DCU...
No R-SAM...
No RFK...
.... so CGW is MIA!

This fits the bill for F-SAM.
I dont think the painted GND or low-voltage are featured here. It's beyond gentle nagging.


> F-SAM Inspections :
Confirm it's missing from OBD access
Visually inspect for signs of water
Lift driver side carpet to search for water swamp


If that does not materialize EZS will be next....