Hi,

 

I have a 2001 Mk1 1.8T 20v 4x4 Octy saloon.  It's a cracking car on only 82K miles, but today the wife rang to say a light had appeared on the dashboard.  It was the ESP / traction control light.

 

I switched off and restarted and the warning light went out.  So I took her for a 10 min drive, and literally seconds before returning home the light came on again and hasn't gone off since...  The ABS light is not on, and I tested ABS.  It is definitely working - so not a wheel speed sensor I assume?

 

From a bit of googling it's looking like brake pedal sensor, one of the inertia sensors or possibly the haldex control unit.  I had a bluetooth OBD interface plugged in and had a look with Torque, but no faults registered.  I think torque can only talk to the engine ECU though, and I'm guessing I need to talk to the ABS ECU, or maybe the haldex unit itself?

 

Will a free copy of VCDS-lite help me identify the fault?  And can I use the bluetooth OBD interface with a laptop, or do I need to find a USB OBD interface cable (I have a couple, but "where" is always the challenge)

 

It seems the haldex units are prone to corrosion, so if I do need to get a new one, does anyone know if the Mk1 TT quattro unit is the same?  There are a few of those available second hand, as I'm certainly not going to fork out £500+ for a new one!

 

Thanks in advance...

 

Olly.

.

 

In case it helps anyone else, I'll answer my own questions

 

The free copy of VCDS lite told me that there is an intermittent issue with the G200 lateral acceleration sensor.  I'm pretty sure this is part number 1J0907651A, and is the same as on similar age Audis.  I am going to order a reconditioned unit, as I don't see much point getting a scrap unit as they do seem to fail with age, and a new unit is of course pretty expensive.  That said, I have read some posts that suggest dry solder joints in the unit are often the problem, so I might have a go at fixing it myself.

 

Looks like a simple 4 bolt job to remove and refit (famous last words) according to this useful post: http://www.briskoda.net/forums/topic/280950-traction-control-code-01423-g200/

 

Cheers

 

Olly

..

 

 

Edit:  Procedure to fix dry solder joints here: http://www.ttforum.co.uk/forum/viewtopic.php?t=435953&p=3146097

Edited 1 May, 201511 yr by orly

Good luck. Let us know how you get on.

I tried to fix the sensor myself.  It's an ar*e of a job.  Took ages to carefully pick out all of the potting compound and then lever the PCB out.  I re-soldered the IC, reassembled and tested.  It worked.  Hooray! 10 seconds later another fault :(

 

I found it only worked reliably when I squeezed it.  So I unsoldered it again to have another go, unfortunately I managed to tear one of the solder tracks off the PCB whilst unsoldering the connector.  Bodge soldered that and reassembled, potted with hot glue gun and tried again.  No worky.

 

So I have forked out £64 for a re-manufactured unit from a guy on ebay which should arrive tomorrow (early versions of this unit had bad solder joints between the surface mount IC and the PCB - loads of Mk1 TTs have this issue apparently so I didn't want to buy a cheapo scrap sensor as it's likely to fail in the future)

 

Hopefully this will fix it.  I am slightly concerned that I might have to calibrate the new unit, as the unregistered version of VCDS-lite does not support this function, and I'm hoping to avoid forking out $99 for a license!  Unless someone in the Slough / Maidenhead / High Wycombe area with a registered copy feels like helping out?  I'd come to you of course!

 

Cheers

 

Olly.

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