OBD Connection Failure - AudiWorld Forums

Go Back   AudiWorld Forums > Audi Models > Audi A4 > A4 (B5 Platform) Discussion
Log In 


A4 (B5 Platform) Discussion Discussion forum for the B5 Audi A4 produced from 1995-2001 B5 FAQ

OBD Connection Failure

Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
Old 11-13-2011, 07:46 PM   #1
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default OBD Connection Failure

Vehicle:
2001 A4 1.8t FWD 5spd
completely stock

Problem:

I cannot connect to the on board diagnostics of the car. I have tried using: authentic ross-tech cable & software, Autozone generic obd2 connector and the ebay connectors. I have to pass emissions soon or I cannot renew my registration!

Notes:

I have tried these possible solutions: disconnect/reconnect abs module, checked k-line (.8v kline to ground/i couldnt get a stable ohm reading) according to ross-tech as long as kline is under 12v it is fine. I have tried a complete reset of the vehicle by disconnecting the battery (although I haven't tried connecting to the obd but I'm assuming this didn't help; call me a pessimist lol).

radio was working and problem existed already, however radio is non operative now. I'm not sure how this happened. Nothing on display but is lit up and no sound from any source (doesn't take in cds or tape). Also when I tried to remove the radio to try and reset the fuse, I broke the clips so it is fairly difficult to remove.


Solutions:

can someone point me in the right direction? Please and thank you. Also is there a way to remove the radio without using the din clips?
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-14-2011, 09:29 AM   #2
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
Vehicle:
2001 A4 1.8t FWD 5spd
completely stock

Problem:

I cannot connect to the on board diagnostics of the car. I have tried using: authentic ross-tech cable & software, Autozone generic obd2 connector and the ebay connectors. I have to pass emissions soon or I cannot renew my registration!

Notes:

I have tried these possible solutions: disconnect/reconnect abs module, checked k-line (.8v kline to ground/i couldnt get a stable ohm reading) according to ross-tech as long as kline is under 12v it is fine. I have tried a complete reset of the vehicle by disconnecting the battery (although I haven't tried connecting to the obd but I'm assuming this didn't help; call me a pessimist lol).

radio was working and problem existed already, however radio is non operative now. I'm not sure how this happened. Nothing on display but is lit up and no sound from any source (doesn't take in cds or tape). Also when I tried to remove the radio to try and reset the fuse, I broke the clips so it is fairly difficult to remove.


Solutions:

can someone point me in the right direction? Please and thank you. Also is there a way to remove the radio without using the din clips?
Symphony radios often get stuck. Those clips were always marginal on single DIN, when they went double DIN they were undersized for the task.

Get (2) 1 1/2 inch plastic putty knives and wedge them in on either side of the stereo. Insert the removal keys. Take off the right side trim panel so you can get your hand behind the head unit and push.

It works every time for me.

Straighten the retaining clips and clean up the area so it's not sticky anymore before you re-assemble.

Everything plugs into the K-line, the favorites to kill the K-line are ABS, Radio, Cluster, central locking, climate control.
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-15-2011, 07:59 AM   #3
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Thank you sir for the reply.

However, I think I broke the din clips for the radio trying to get the unit out. Is there a way I can get it out; like panel/trim removal?

As for the KLine hang up, could a full reset (battery disconnect) possibly free it up?
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-15-2011, 08:52 AM   #4
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
Thank you sir for the reply.

However, I think I broke the din clips for the radio trying to get the unit out. Is there a way I can get it out; like panel/trim removal?

As for the KLine hang up, could a full reset (battery disconnect) possibly free it up?
If you really broke the clips it wouldn't still be stuck in there.

You bent the clips, wedging the putty knives in there usually allows it to slide out. Pushing from the back also helps. Remove the panel on the side of the console (where the passengers right foot would be) you can see the back of the radio from there.

You may have to break the trim to get it out otherwise, all of the fasteners holding that part of the console are behind the trim. The radio needs to be removed to access them.

As to the K-line, disconnecting the battery rarely does that help. You may make things worse as now all the learned setup info has been cleared.
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-15-2011, 10:43 AM   #5
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by AudiMick View Post
If you really broke the clips it wouldn't still be stuck in there.

You bent the clips, wedging the putty knives in there usually allows it to slide out. Pushing from the back also helps. Remove the panel on the side of the console (where the passengers right foot would be) you can see the back of the radio from there.

You may have to break the trim to get it out otherwise, all of the fasteners holding that part of the console are behind the trim. The radio needs to be removed to access them.

As to the K-line, disconnecting the battery rarely does that help. You may make things worse as now all the learned setup info has been cleared.

Hmm I see, well after disconnecting the battery, still not able to connect with the Autozone scanner (readily available to be). I'm not sure if this is relevant, I forgot to mention before, I have the air bag light on.

I'll try and get the radio out today. Do you think that will really help my OBD connection problem?

Do you think I have a major problem here? I mean since all the common remedy (disconnect abs module, check Kline voltage etc.) isn't working to fix the OBD connection. I guess what I am really trying to say is I am a bit at a loss for a plan of action right now. What do you think I should do?


Thank you so much
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-15-2011, 12:05 PM   #6
Tech Guru
 
4Driver4's Avatar
 
Join Date: Oct 2002
Posts: 33,261
Default

Start by getting a VAG-COM.
__________________
4Driver4

Growing old is mandatory; growing up is optional.

2005 A6 Sedan Q 3.2 (wife's whip)
2003 S8 (Q Ship)
2000 A4 Avant Q 2.8 (daily driver)
1999 BMW M Coupe (clownshoe)
1980 VW Scirocco (mid-life crisis car)
1983 Mazda RX-7 (revolutionary sports car)
1999 Mazda Miata SSB (track beotch, no plate)
2003 GMC Yukon Denali XL (the anti-earth)
2004 Dodge Dakota (hey, at least it's stick and 4x4)
4Driver4 is offline   Reply With Quote
Old 11-15-2011, 12:11 PM   #7
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
Hmm I see, well after disconnecting the battery, still not able to connect with the Autozone scanner (readily available to be). I'm not sure if this is relevant, I forgot to mention before, I have the air bag light on.

I'll try and get the radio out today. Do you think that will really help my OBD connection problem?

Do you think I have a major problem here? I mean since all the common remedy (disconnect abs module, check Kline voltage etc.) isn't working to fix the OBD connection. I guess what I am really trying to say is I am a bit at a loss for a plan of action right now. What do you think I should do?


Thank you so much
All you have established is that the K-line voltage signals are within limits. That test doesn't determine if all the modules are OK. You haven't figured it out yet if one is blocking communications.

You can run K line diagnostics with only one module connected in the car.

And since the Airbag is lit there's another potential culprit.

My state (WA) allows a sniffer test on OBDII cars if the port is not working, you might check with your emissions testing facility on what you need. This happens on a lot of vehicles and they don't want you damaging their equipment either.
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-15-2011, 01:47 PM   #8
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by 4Driver4 View Post
Start by getting a VAG-COM.
Thank you for the response, not sure if you read the entire thread, (ref. to original post) I tried to connect with a real authentic ross-tech vag-com to no avail.
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-15-2011, 01:50 PM   #9
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by AudiMick View Post
All you have established is that the K-line voltage signals are within limits. That test doesn't determine if all the modules are OK. You haven't figured it out yet if one is blocking communications.

You can run K line diagnostics with only one module connected in the car.

And since the Airbag is lit there's another potential culprit.

My state (WA) allows a sniffer test on OBDII cars if the port is not working, you might check with your emissions testing facility on what you need. This happens on a lot of vehicles and they don't want you damaging their equipment either.
Well, emission test through the tail pipe would be awesome, except I have a check engine light as well. So I really have to get the communication going.

When you say "run K line diagnostics with only one module connected," are you saying disconnect all modules that communicate with K line and test one by one?
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-15-2011, 03:02 PM   #10
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
Well, emission test through the tail pipe would be awesome, except I have a check engine light as well. So I really have to get the communication going.

When you say "run K line diagnostics with only one module connected," are you saying disconnect all modules that communicate with K line and test one by one?
They are in parallel, so if you can get just one to work you would know your wiring and scanner is OK.

Have you checked to see if you have continuity between the OBD port and any of the modules?
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-16-2011, 11:18 AM   #11
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by AudiMick View Post
They are in parallel, so if you can get just one to work you would know your wiring and scanner is OK.

Have you checked to see if you have continuity between the OBD port and any of the modules?

Thanks for the lead you've given me here, would you be able to point me on a spec sheet? Basically something to go on with info. I got this pin out from the ross-tech site (on the bottom). Maybe possible readings and procedures. Thanks.

http://www.ross-tech.com/vag-com/aftermarket-radio.html
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-16-2011, 11:50 AM   #12
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
Thanks for the lead you've given me here, would you be able to point me on a spec sheet? Basically something to go on with info. I got this pin out from the ross-tech site (on the bottom). Maybe possible readings and procedures. Thanks.

http://www.ross-tech.com/vag-com/aftermarket-radio.html
You need a Bentley manual. I would check continuity between K line on the OBDII connector and either the radio or the climate control.

F K -line is Plug III pin 3. So unplug the radio stick your meter probe in that pin in the lradio oom and the other test wire in pin 7 of the OBDII connector.

Measure ohms, should be close to zero.
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-16-2011, 02:50 PM   #13
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by AudiMick View Post
You need a Bentley manual. I would check continuity between K line on the OBDII connector and either the radio or the climate control.

F K -line is Plug III pin 3. So unplug the radio stick your meter probe in that pin in the lradio oom and the other test wire in pin 7 of the OBDII connector.

Measure ohms, should be close to zero.
Yeah I know the Bentley manual would be awesome, but don't have one yet.

Checked the radio harness Kline for continuity, and got .4/.5 reading. Is that fairly close? (note: had to use a little metal piece to stick into the obd pin 7) The .4 resistance could be due to that?

As for the climate control, I've been searching for awhile and could not find a wiring pin out for the harness. (except for a post you've written a while back saying that it is the purple wire). Any help would be greatly appreciated.

Also, are there any pdf version of the manual for fr**? (not sure if this is against forum rules)
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-16-2011, 03:43 PM   #14
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

AudiMick

I did some more searching, and decided to widen my search. Although my car seem stock and all, there have been many owners before me. I read somewhere of chipped ecus causing no communication with obd. Could this be possible and is there a way of checking this visually of the ecu?
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-16-2011, 05:05 PM   #15
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

AudiMick,



I finally made headway. I disconnected the harnesses to the radio and climate control unit. Decided to try and connect the obd reader; no link (key on engine off). I decided to try and scan with key off and was able to make connection (p0411 code). Tried the connection again with the key on; no link. Could have possibly been able to connect all along just as long as the key was off >.<

Well, (P0411 SAIC incorrect flow detected) I've kinda looked up this error code. What I am more interested in is why I was only able to connect with the obd in this manner. I have always thought the car must be in the key on position to connect with the OBD.

I feel that this may be the symptom that could crack the case wide open, since I feel this symptom is way too peculiar (correct me if I am wrong though).


As for the code, a lot of what I've read was as simple as the vac lines to the EGR. So I'll check those first. Thank you so much for the help, I just need a little more lol.

Louis
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-17-2011, 06:47 AM   #16
AudiWorld Super User
 
AudiMick's Avatar
 
Join Date: May 2002
Location: Redmond WA
Posts: 5,119
Default

Quote:
Originally Posted by ruckus1027 View Post
AudiMick,



I finally made headway. I disconnected the harnesses to the radio and climate control unit. Decided to try and connect the obd reader; no link (key on engine off). I decided to try and scan with key off and was able to make connection (p0411 code). Tried the connection again with the key on; no link. Could have possibly been able to connect all along just as long as the key was off >.<

Well, (P0411 SAIC incorrect flow detected) I've kinda looked up this error code. What I am more interested in is why I was only able to connect with the obd in this manner. I have always thought the car must be in the key on position to connect with the OBD.

I feel that this may be the symptom that could crack the case wide open, since I feel this symptom is way too peculiar (correct me if I am wrong though).


As for the code, a lot of what I've read was as simple as the vac lines to the EGR. So I'll check those first. Thank you so much for the help, I just need a little more lol.

Louis

Well at least you know it should work, so we are back to one of the modules blocking communication.

The resistance you measured is fine > 1 ohm that just the resistance of the wire.

There is no EGR on your car, so that could be bogus. Vag.com would probably give you the correct code.

There is a Secondary air injection pump, I have heard of the relay for these shorting out and thus running when the ignition is off (drains the battery eventually ) that could be why you are able to see that error.

See if you can reach the pump and feel if it's running. You might also unplug it , is it interfering with the other modules?

Anything is possible with a flashed or chipped ECU. If it's flashed you won't be able to see it's not stock. If it's a soldered chip maybe.
__________________
2001 180 TTQ coupe (sold)
1976 Triumph Spitfire
2008 A4Q 2.0T (sold)
2003 A4Q 1.8T (sold)
1996 A4Q (sold)
AudiMick is offline   Reply With Quote
Old 11-17-2011, 09:47 AM   #17
Audiworld Junior Member
 
Join Date: May 2011
Location: St. Paul MN/Lombard IL
Posts: 27
Default

Quote:
Originally Posted by AudiMick View Post
Well at least you know it should work, so we are back to one of the modules blocking communication.

The resistance you measured is fine > 1 ohm that just the resistance of the wire.

There is no EGR on your car, so that could be bogus. Vag.com would probably give you the correct code.

There is a Secondary air injection pump, I have heard of the relay for these shorting out and thus running when the ignition is off (drains the battery eventually ) that could be why you are able to see that error.

See if you can reach the pump and feel if it's running. You might also unplug it , is it interfering with the other modules?

Anything is possible with a flashed or chipped ECU. If it's flashed you won't be able to see it's not stock. If it's a soldered chip maybe.
About the code, I misspoke, I looked at the first thread I found and they said egr. However, upon looking into it more, it is related to the SAI. I looked at the manual for the code reader, it too said SAI. I don't believe it is the air pump itself. It could be one of the vac lines. I looked at the schematics for the system, and did a quick look at my car I noticed a pretty tethered vac line.

However, I'd like to go back to the obd communication failure. It came back this morning. After I made connection last night, I left the car in the garage (I never started it let alone turn the key on). I tried again to do a communication today and nothing; not even during key off engine off position.

I did reconnect some electrical related items before trying the communication, it was just the harness for the light for the ashtray and the harness for the cig lighter. After those two I decided to check one more time and see if the connection is still there; nope not working. I even tried disconnecting those two again and nothing.

I was overcome with frustration when I found this, however, it quickly disappeared and became more intrigued and perplexed at the situation. I thought I was done with the connection error. Oh Audis lol.
__________________
I'm a No.Ob!!!
2001 FWD A4 1.8T 5Speed
Stock as a grocery shelf
--cooler sig pending
ruckus1027 is offline   Reply With Quote
Old 11-21-2012, 04:56 PM   #18
AudiWorld Newcomer
 
Join Date: Nov 2012
Location: http://www.obdcheap.com/autop-s620-obdii-eobd-code-reader.html
Posts: 1
Default U480 OBD2 CAN BUS & Engine Code Reader

U480 OBD2 CAN BUS & Engine Code Reader

Online Shopping Security

High Quality, Low Price & Excellent Service

Color : orange

Weight : 300g

Dimension:300*170*60mm

Regular Price: $29.99 Buy it Now : $25.20



Supported Vehicle:


Suitable for almost all cars

Product Description


Description:
With U480 code reader, you may quickly find out trouble causes (troubleshooter) of electronically controlled systems on your car, by simply connecting U480 with the 16 PIN diagnostic socket, via reading the trouble code (DTC) shown on U480, identifying, locating and checking out trouble causes with attached user's manual.
Function:
1.Works on all 1996 and newer cars & trucks that are OBD II /EOBD compliant including CAN, VPW, PWM, ISO and KWP2000 protocols*

2.Reads and clears generic and manufacturer specific Diagnostic Trouble Codes (DTCs) and turns off check engine light*

3.Supports multiple trouble code requests: generic codes, pending codes and manufacturer's specific codes*

4.Retrieves VIN (Vehicle Identification No.) on 2002 and newer vehicles that support Mode 9*

5.Highly reliable and accurate*

6.Easy-to-read crystal-clear backlit 2-line LCD display*

7.Easy to use with one plug-in*

8.Stand-alone unit with no need for an additional laptop computer to operate*

9.Small in size and conveniently fits in your palm Performs continuous DTC scan*

10.Safely communicates with the on-board computer*

11.No batteries needed-powered via detachable OBD II cable
Specifications:
16-pin OBDII Standard Socket*

Voltage: DC 10V~12V*

Temperature: -10 ~ 40*

Display: 2 line LCD
__________________
http://www.obdcheap.com/u581-live-data-obd2-eobd-scanner-can-bus-code-reader-sc30.html
oconnor is offline   Reply With Quote
Old 08-31-2014, 08:08 AM   #19
auh
AudiWorld Newcomer
 
Join Date: Sep 2010
Location: Highland Park, IL
Posts: 4
Default

Did you ever solve this? My cars obd2 is no longer connectable and I can't pass emissions with out them connecting to my obd2
auh is offline   Reply With Quote
 
 
 
Reply

Tags
2000, 2001, abs, audi, connection, connector, disconnect, end, fail, failure, obd, obd2, quattro, tt, view

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 10:43 PM.


Copyright 2014 AudiWorld.com Audi Enthusiast Community