Argh ECU Fault Code Reading Error HELP!!!

[Tuccy]

Hello all..

A few weeks ago i bought myself a 98 clk320 coupe, in wanting to look after the car properly i decided to do a aft oil/filter and gasket change, i read many posts on here to gain the merc specifics, this all went well and the car is driving much much better now.

Now My Prob!!!

I then decided to connect the car to Fault code reader with intentions of clearing all faults, then drive the car for a few days, then checking which faults had returned in order to maintain and repair these.

ive tried 3 different code readers with various different leads and 2 different 38pin merc adapters, yet all return these simular errors:

cannot connect with vehicle
vehicle not responding
waiting for responce from vehicle

i then decided to load software onto my laptop and try this way, but even my laptop cannot connect to the car.

i removed the plastic cover from the ecu housing to check for loose corroded pins in the obd socket, the 38pin socket in like new, BUT ive noticed someone has been tampering with the wires entering one of the ECU sockets, 3 wires have been cut and 3 other wires have been soldered and taped up in there place, this is hard to explain so i will post pics later.

Is anyone aware of any issues of a aftermarket modification, addon etc which would require this to be done?? the reason i ask is because the work looks like a very neat diy job or a not so neat dealer job..

Ive also read somewhere of a procedure where i need to get the car into mode ready for Fault finding, this contains instructions of driving the car at various speeds/stopping etc within set times!!!! is there any truth in this? am i required to do this in order to get the code readers to work?????

please please help im at my wits end
thanks in advance Tuccy

 

[Miffy]

Depends on the readers your using, you didnt give any info so its all guess work. From what I have seen, and indeed my own fault reader, the ignition needs to be at position 2, or engine running.

Oh by the way, welcome to the forum

 

[Tuccy]

thanks for the speedy reply



the various fault code readers ive tried are:

1: GENDAN GCR05 EOBD / OBDII

2: ELM327 OBD to RS232 Interpreter

3: MERCEDES BENZ C CLASS FAULT CODE READER & RESETTER - ECUTMERCC1

4: GS400 Scanner OBD 2 Can-Bus Code Reader canbus OBD2


Ive tried these with the ignition off, in position 1, in position 2 (as advised)
but not with engine running? maby this is where im going wrong...???

Also here is a pic of what my ECU connection looks like:

the wires that have been cut enter the slieving with the rest of the loom,
and are therefore no longer connected to whatever they feed


the wires that have been added are taped together neatly, they then exit the ECU housing cable tied onto the outside of the original loom, then they make their way around the top of the engine, down the front of the engine, and around the backside of the altinator, i cannot track these any further yet as i would need the car on ramps to do so..

anyone any idea`s please

tuccy

 

[Cole@MBS]

Thats the engine ECU, why would someone cut them wires???

 

[Tuccy]

Thats the engine ECU, why would someone cut them wires???

Exactly!! Ideas Anyone
im tempted to remove the added wires and reconnect the original wires to see what happens, im just reluctant incase i kill the car or ecu

 

[Cole@MBS]

Looking at the photo i would guess some cheap alarm has been fitted and the cuts are into the fuel pump harness,

Not a nice picture!!

 

[Tuccy]

Thanks S-A-M / U-N-I-T really appreciate your help and suggestions.

to my knowledge and vin check the alarm on the car was fitted from factory. unless for some reason it has been replaced??

Here is some more info if it helps identify the mistery wires

Original wire colours that should be connected to ecu plug are:

Brown/Black =Pin Socket No 16 on ecu plug-----Cut and connected to Added Black wire
Red/Yellow =Pin Socket No 15 on ecu plug-----Cut and connected to Added Red wire
Grey/Brown = Pin Socket No 17 on ecu plug-----Cut and connecyed to Added Blue wire

hope this helps, im havng difficulty in tracing these wires on the vast wiring diagram to decifer what it is they feed...

 

[Hertfordshire Merx]

I would agree with SAM UNIT that there probably would have been an attempt to have fitted an alarm or immobiliser. Aftermarket anti theft systems do not work well when fitted additionally with factory fitted systems as they interfere.

With regards to your answer I am making a lot of hours from other motor traders using code readers to play around with Mercedes, in some cases making a mess of adaptations and coding errors. The Star was invented to couple with Mercs obviously and no other out there will do it better! The only close ones are Auto Logic and maybe the Snap-On Solus or Modis. All of which are thousands of pounds. I wouldn't personally use an aftermarket code reader and to be unbiased its worth the cost in diagnosis time for dealers or a good independant to do a full report for you, rather than an inexperienced person not knowing how to use equipment properly or interpret the values/fault codes.

 

[jibcl500]

Sorry to butt in but does the ignition need to be on for your code readers to work.

I have a carsoft system on ebay if interested, works very well.

jib

 

[Tuccy]

thanks for the input everyone, mistery wires finally identified

it would appear these added wires are replacment wiring for the oil sensor on the bottom of the engine sump, this matches the pins they are connected to on the ecu plug and where they run to under the engine, it would seem the original oil sensor wires had got damaged at some time and this is how they have been replaced. Phew

thanks tuccy