Somewhat of a unique problem.

[97stroker]

Somewhat of a unique problem. (OBDII not functioning)

I have an 03 golf tdi. It had a check engine light but when I hook vagcom to it it cant connect to any modules. I unplugged (to check) all the fuses that had the engine symbol and unplugged 2 relays behind the kick panel and after I did this and started the car the CEL was gone. It still wont connect to VAG, my 75 dollar autocrapper OBDII reader, or my flashzilla. It had the double din when I bought it but I replaced it with a single din JVC and a pocket but never had any problems connecting to the car after I installed the stereo. It doesn't have the multifuntion steering wheel. The power locks, windows, and mirrors all function. I haven't really been able to inspect the ecu or its connections just yet, hopefully tommorw. Anything specific you guys think I should look at? I am at a loss as to what to look at next.
Most of the threads I have read about not being able to connect to the ECU all state its most likely the aftermarket stereo but they also say the vehicle doesnt run. Mine fortunately and unfortunately is running like there isn't a problem minus the CEL that was on before, but is now off after I unplugged and replugged the fuses and 2 relays.
Thanks guys.

 

[joewilhite]

data link connector, may have a bad connection or something is tied into it thats not supposed to be their.

 

[97stroker]

Not really sure what to look for ornery than at the condition of the wires and connectors. All looks fine. It definitely gets power at the connector and it gets the initial red light of the vcds cable and then turns green.

 

[Perfectreign]

Data link connector

http://www.ross-tech.com/vag-com/aftermarket-radio.html

 

[97stroker]

Mines an 03 so looks like I'll be pulling the radio tomorrow morning! Very helpful reading though

 

[97stroker]

Well it most definitely is NOT the aftermarket radio. I pulled it out this morning, including the aftermarket adapter so it was just the original radio harness and I still cant connect any of my devices to the car. Any other ideas guys?

 

[joewilhite]

just because you have power at the data link dosent mean its going to communicate .
need to ck all points of wiring for proper volts. on that 09 you will have high speed comms.
I've seen other modules take down comms. for a whole car but still run.
i think you have can-bus, need to find a book on that connector

 

[Hyde7278]

Disconnect the ABS connector at the ABS module/pump. I've seen the ABS make it not possible to connect to other modules.

Big problem in Audis and also have seen it in a few GM's also.

 

[97stroker]

Took the connector off the ABS pump and still no luck. Im gonna have to take the wiper cowling off and take a look at the ECU connections and inspect them. There is a hole in it just the the passenger side of the ECU connectors, are they weatherproof or could moisture get in there and fubar that up? Thanks for the suggestions this far keep them coming please!

 

[jettawreck]

Weatherproof connections on the ECU.
Hole in the wiper cowling? Possible a rodent/critter been in there and did some alterations? Seen everything from mice to weasels get in a hole less than the size of a dime and make for a variety of problems.

 

[97stroker]

There are quite a few mink farms around! In fact theres one right down the road from where it was parked for 2-3 months. My brother in law thought the bad sound was "deep in the motor" but it just needed a tensioner and alternator pulley! I never should have let him take "ownership" of the car, it needs a lot of love.

 

[97stroker]

I failed to mention 3 problems that might help the diagnosis problem.

My brother in law replaced the drivers side window regulator so could that hang something up in the data link connection?

He also mentioned the gauges sometimes would just shut off and then restart, the needles went to zero the lights went out in the dash but the car was still running and the headlights stayed on (i have a euro switch and drl's disabled). How often this happened I'm not sure but often enough to remember and tell me about it.

And last but not least, sometimes the idle goes up to 1100 and back down to what? 925? Anyways i actually did see this one happen today. My temp was at normal 190. I have a malone stage 1.5 tune on it with the dynamic idle so when its cold it normally does idle at 1100 until it warms up a bit. It does this every morning with no problems. I'd flash it back to stock but you already know i can't.

Sorry for the long post, any help is greatly appreciated!

 

[Seatman]

Did you check the actual connections to the obd port as per the link posted earlier? Need to check the power and ground are definitely present.

If the ecu was at fault it'd be the only thing you couldn't connect too, wouldn't stop access to the ccm, cluster etc.

If you can't connect to anything it's got to be the obd connection I'd have thought.

 

[Alchemist]

All the modules communicate with each other over a CAN bus. There is a Gateway in the Instrument Cluster which translates CAN Bus to K Line for the OBD connector.

Try connecting to the Gateway, as that is the first stop for OBD data.