ECU won't connect to VAG-COM

hunker7 · 08-11-13, 05:27 PM

Hi guys. I had poblem with my TPS sensor, so took my car to the garage, and they checked everything and said that ECU is at fault. So I got another one same part number from the same car (Audi 100). I replaced the old one, and thought I'll connect VAG-COM and see if there are any faults present, but error dialog like this pops up;

Any idea what might be wrong?

inne3quattro · 08-11-13, 05:48 PM

Is it running ? Or the same fault as before you replaced the ecu ?

hunker7 · 08-11-13, 06:40 PM

Quote:

Originally Posted by inne3quattro

Is it running ? Or the same fault as before you replaced the ecu ?

It does run. I can start it and drive it, but I am not sure if it runs any better.

inne3quattro · 08-11-13, 08:35 PM

Doesn't sound like a ecu fault to me as it's running, possibly in limp mode, is the management light on ? How did you know it was a tps ? Was there a code in the old ecu, what was it, and what happens if you put the old ecu on and plug in ?

hunker7 · 08-11-13, 08:45 PM

No lights are on on the dash. On old ecu it was showing error for TPS. So took it to garage, they checked wiring that was fine, and sensor as well, as it connects straight to ECU it could've only been the ECU. Didn't try plugging old ecu back in, I might just go down to the same garage and have a chat with electrician what he thinks. Could it be that the error is still there?

inne3quattro · 08-11-13, 08:50 PM

Your original ecu communicated with vag com, which is a better place to be than where you are now ! What was the fault with the tps ?

hunker7 · 08-11-13, 08:59 PM

Quote:

Originally Posted by inne3quattro

Your original ecu communicated with vag com, which is a better place to be than where you are now ! What was the fault with the tps ?

It basically said it's 91 degree open and it didn't change when throttle's being operated.

inne3quattro · 08-11-13, 09:07 PM

Wouldn't that be full throttle from idle ?

hunker7 · 08-11-13, 09:17 PM

Quote:

Originally Posted by inne3quattro

Wouldn't that be full throttle from idle ?

Yh but it knows that that ain't right so ir goes into default mode.

inne3quattro · 08-11-13, 09:40 PM

Ok, so the ecu is being told the throttle is wide open, but air flow, rpm etc don't tally up. Tps is a measured resistance, and this signal could be corrupt by a wiring fault, try putting the old ecu back on, unplug the tps and see what degree it reads, ignore the other codes it may throw up

08-11-13, 08:45 PM	#5
hunker7 Grown up member Classic Audi Club Member Join Date: Nov 2012 Location: Leeds, London Posts: 449	No lights are on on the dash. On old ecu it was showing error for TPS. So took it to garage, they checked wiring that was fine, and sensor as well, as it connects straight to ECU it could've only been the ECU. Didn't try plugging old ecu back in, I might just go down to the same garage and have a chat with electrician what he thinks. Could it be that the error is still there? __________________ '93 Audi 100 Avant - R.I.P '92 Audi UrS4 Avant - SOLD '93 Audi UrS4 Avant '05 Audi A8 D3 4.2 V8 - LPG

08-11-13, 05:48 PM	#2
inne3quattro Grown up member Classic Audi Club Member Join Date: Oct 2009 Posts: 325	Is it running ? Or the same fault as before you replaced the ecu ?

08-11-13, 08:35 PM	#4
inne3quattro Grown up member Classic Audi Club Member Join Date: Oct 2009 Posts: 325	Doesn't sound like a ecu fault to me as it's running, possibly in limp mode, is the management light on ? How did you know it was a tps ? Was there a code in the old ecu, what was it, and what happens if you put the old ecu on and plug in ?

08-11-13, 08:50 PM	#6
inne3quattro Grown up member Classic Audi Club Member Join Date: Oct 2009 Posts: 325	Your original ecu communicated with vag com, which is a better place to be than where you are now ! What was the fault with the tps ?

08-11-13, 09:07 PM	#8
inne3quattro Grown up member Classic Audi Club Member Join Date: Oct 2009 Posts: 325	Wouldn't that be full throttle from idle ?

08-11-13, 09:40 PM	#10
inne3quattro Grown up member Classic Audi Club Member Join Date: Oct 2009 Posts: 325	Ok, so the ecu is being told the throttle is wide open, but air flow, rpm etc don't tally up. Tps is a measured resistance, and this signal could be corrupt by a wiring fault, try putting the old ecu back on, unplug the tps and see what degree it reads, ignore the other codes it may throw up