No comm. at test port? can I get codes manually?

cruciform

Well-known member
Joined
Apr 15, 2004
Location
Buffalo, NY
TDI
1996 Passat TDi wagon
Ok, so I took my car to autozone the other day to get the codes for my CEL, as it's been on for some time now.

the machine could not communicate with the computer-
tried another autozone, and got the same results.. I pulled the diagnostic port out to check the pins, and they all look OK, and in place.. I don't have VAG COM right now, and was wondering if there is a way to check the test port? is there a way to pull the codes manually?

the car is a 96 TDi passat wagon..

Cheers,

Percy.
 

GMCpatrick

Veteran Member
Joined
Aug 16, 2001
Location
Atlanta
Percy - Please pardon the silly question, but was the car running?

If you'll update your profile with your location, there may be someone nearby willing to help.
 

fastvicar

Veteran Member
Joined
Aug 11, 2003
Location
Lancaster, PA, USA
TDI
1996 Passat, Indian Red
Aftermarket stereo? Pull it out & disconnect it for diagnostic session. My Alpine wouldn't let my Passat talk, either.
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
If you still have the original BK ECU there are SOME codes that can be obtained via a blink code output. Insert the ignition key, turn it to ON, not START. Press the accelerator completely to the floor and release it completely five times within five seconds. The MIL will begin to flash a four digit code, count the flashes. NOTE: the code of the flash output does not match the VAG COM code. There is a separate look-up chart in the Bentley.
The "smoke fix" replacement ECU for the 96 is a GQ series. This ECU does not support the blink code, nor does the FA ECU for the 97 Passat.
 

RIP TDI

Top Post Dawg
Joined
Feb 16, 2000
Location
Santa Barbara, CA
TDI
'15 GSW SE 6MT...... '01 Golf GLS 5MT.... '96 Passat Variant....
Aftermarket stereo? Pull it out & disconnect it for diagnostic session. My Alpine wouldn't let my Passat talk, either.
The K-wire should not be connected to an aftermarket head unit at any time. A VW-specific harness adaptor should already eliminate this connection. If not, make sure to disconnect the K-wire permanently.
 

Toronto_Vento

Top Post Dawg
Joined
Nov 7, 2002
Location
Richmond Hill, ON
TDI
01 Baltic Green Bora
Strange...had a member come to a local GTG. Tried three laptops, couldn't communicate with his car. Yes, aftermarket stereo. Yes, we pulled it out. No, still couldn't communicate with the car. No idea what that was about as we couldn't solve the problem.
 

Oilheat

Veteran Member
Joined
Sep 22, 2003
Location
So. NH
TDI
'91 Jetta, A3 TDI eng.
My 98 Jetta stuffed into a 91 wouldn't communicate with the engine controller until I restored the wiring correctly.
Way, way up on top of the fusebox to the left of the GP maxifuse is a separate junction box for the diagnostic circuit, with a bunch of grey and black wires going to it. All the communication wires from the various controllers meet here, as does the wire from the diagnostic port. By various controllers I mean the engine controller, airbag controller, seatbelt controller I think, and the security module, I think.
With my car it was a simple matter of not remembering to make the connections eight months after taking them apart; but this site could be a logical place to investigate lack of communication from the test port--the wire ends are simple snap-in connectors.
BTW, Messrs Bentley are very reluctant to divulge the above information. The only mention in the schematics that I could find occured in a wiring diagram for a gasser several years removed from my car.
 
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