Hi, Im new on this site, but actually im old user.. mostly i read others car problems and solutions. But today i wanted to Add some Weird sh it what i suspected and you dont believe what caused it! That car came from other shop, they suspected wiring issue, because all what they tested didnot change anything in first place! Also I did not find any electrical issue, and car went back to that shop! Owner wanted also turbo change what "whoever sugested that". Basicly there was full parts change style fixing attempts, because nothing made any sense! Everything was tested and replaced, but error was still there. But.. we all tested those parts one by one even i did that one by one as i usually do!

Car Data:
Engine Code: D5244T4
Engine: 2400 cm³
Engine Power: 136 kW
Variant: BW7140

Symptoms when car came:

• Car lost engine power suddenly while driving. (Limited RPM to 2000-2500)
• Engine runs like a cr ap, shaking and makes weird noise.
• OBD Scanner was able to communicate only with Interior Modules.

Only DTC i got was:

• DIM (Driver Information Module) C200262 Odometer Tampered. Algorithm Based Failures. Signal Compare Failure
• DIM (Driver Information Module) U300045 Control Module. System Internal Failures. Program Memory Failure
• PDM (Passenger Door Module) B118F00 Left Front Window. General Failure Information. No Sub Type Information
• PDM (Passenger Door Module) B119100 Right Rear Window. General Failure Information. No Sub Type Information
• DDM (Driver Door Module) B118E00 Left Front Window. General Failure Information. No Sub Type Information
• DDM (Driver Door Module) B119000 Left Rear Window. General Failure Information. No Sub Type Information
• MMM (Multimedia Module) U220041 Control Module Configuration Memory Corrupt .System Internal Failures. General Checksum Failure
• MMM (Multimedia Module) U220044 Control Module Configuration Memory Corrupt .System Internal Failures. Data Memory Failure

Checked:

• All Sensors on Engine Bay, even tested with "known good sensors and parts as they did it from previous shop" (Nothing was out of Spec).
• Measured all Voltages, Ohms, Grounds and everything was on Specs, there was nothing Shorted to (Ground/Power/Signal).
• The Only way to get data from ECU, TCU, ABS... etc was to make "Module by Module scan and Ignition ON/OFF technics"!

OBD was connected, selected was ECU and As you turned ignition to positon 1 (Not to start engine) then you had 20-30seconds window to read CAN High data (but not Always it worked). Then CAN High droped, then repeated same procedures from scanning and cleaning DTC-s
First Round i got before replacing parts (as is suspected right away MAF and clearing codes):

• ECM (Engine Control Module) P010F16 Mass Or Volume Air Flow Sensor A/B Correlation. General Electrical Failures. Circuit Voltage Below Threshold
• ECM (Engine Control Module) P067200 Cylinder 2 Glow Plug Circuit. General Failure Information. No Sub Type Information
• ECM (Engine Control Module) P067400 Cylinder 4 Glow Plug Circuit. General Failure Information. No Sub Type Information
• ECM (Engine Control Module) P250A17 Engine Oil Level Sensor Circuit. General Electrical Failures. Circuit Voltage Above Threshold
• CEM (Central Electrical Module) B10EA14 Positive Temperature Coefficient Heater. General Electrical Failures. Circuit Short To Ground Or Open
• CEM (Central Electrical Module) B110977 Passenger Door Central Locking Motor. Mechanical Failures. Commanded Position Not Reachable
• CEM (Central Electrical Module) B1C8214 Headlamp Washer Relay A. General Electrical Failures. Circuit Short To Ground Or Open
• CEM (Central Electrical Module) U030100 Software Incompatibility With ECM/PCM. General Failure Information. No Sub Type Information

And Also DIM, PDM, DDM, and MMM errors!
Nothing changed, then i Unpluged MAF and MAP.. Cleaned DTC-s and ... NOTHING changed, i got extra codes for missing MAF and MAP only, then i measured wirings from MAF and MAP to ECU .. all fine. Later i measured ALL wirings from other sensors, because i was out of options! All Fine!

Then i started suspect FUEL issue (it was downhill running)
From live data, i got ignition 1 325-375PA and Ignition 2 engine running 320-425PA jumping as engine shakes and as engine did die it fall right to 6.5PA.. just as it started indicating its fuel related issue.. Then we replaced fuel rail with sensors from working car... Nothing! Same problem.. but still we did not know what cause CAN High to drop down!
In some point i even tested CEM connectors, by removing engine bay connectors from CEM... (turned out it was impossible, some wiring was mixed with other connectors and it was pointless operation, it did gives me another wrong info as something in interior turnes CAN High down, because i didnt know that connectors was mixed and based from wiring data all enginebay wiring is ONLY in 1 plug etc.. Missinformation and Parts Thrower way to start assuming everything..

Car went back to previous shop because i did tell based my measurements, its not wiring or electrical related problem, i did not find anything out of spec, it have to be mechanical issue! Later i got confirmation, that car got another parts throw in.. turbo as owner heard from other places it have to be turbo.. nothing, same problem and then they replaced MAP and MAF together... Volaaa, car is fixed!


Then i got those replaced sensors, measured them again.. all fine, but if you apply voltage longer than 20-30 seconds as CAN problem started in car.. then i noticed some weird sh it! MAF Sensor output data pin to ECU started show short randomly, out signal voltage jumped randomly up and input voltage started shorting randomly down in short period, but not to 0. As MAP sensor "warmed up" a bit, internally something shorted out voltage dropped to 0 and full short started to appear. As them both "cooled down".. for 2-3 sec they acted as Normally working sensors again, untill 20-30 seconds of working time all went back to hell!

Then there is question... how and why there is sensor spec data, if there is that kind of problems and no bulletin for diagnose. How you know when its damaged parts if it act like its on spec but not always and acted up in specific condition!

Car is now fixed, some DTC-s did stay as owner credit card decided!

Its posted for information basis to other!