# Scanned code 01312 ESP light



## big_nige (Mar 2, 2013)

It's come up data bus drive fault code 01312 - any ideas what it is as i cant find it anywhere?

Cheers


----------



## T3RBO (Dec 9, 2003)

Not a lot of info but

http://wiki.ross-tech.com/wiki/index.php/01312


----------



## big_nige (Mar 2, 2013)

No, not a lot  the previous owner said it went on when he went through a puddle. The light is out until you have3 driven a few yards also...


----------



## Skeee (Jun 9, 2009)

I'm no expert on the Audi Databus but as RossTech says it's a wiring connection issue.
It may be possible to narrow it down by looking at all the ESP Sensor readings using vagcom in the ABS Measuring Blocks, Blocks 3-6.
If any of those are out or hunting wildly then that will help.
If not then it's a case of working trough the wiring.
It may be difficult to check with a basic multimeter as the power supply an earth can be good but the databus signals are obviously being corrupted due to a break/high resistance in the wiring which may only occur under vibration or heat etc.

If it was me firstly I would check all the ESP related connectors. Just remove them give them a blow with dry air and spray with contact cleaner and dry with air then reconnect.
Start with the big ABS connector J104 with the sliding collar and work your way around to all the sensors, Lat, Long, two brake pressure sensors and steering wheel/clock spring. 
The brake sensors are visible but hard to reach, the lat long are fairly easy to reach but the clock spring is under the steering wheel so I'd leave that to last!

Clear the fault first and see how often it returns. 
Ideally you don't want to disconnect anything until the fault is present, ie
next time it comes on permanently, scan it and the second line fault number will end in XX-00 (not XX-10 which is intermittent) also when you clear it in the Faults Page it will return instantly.
When you've located the sensors it might show up if you "gently" rattle the plug connector wiring whilst observing the ABS Measuring Block readings for each sensor you are checking.

The light comes on after a few yards driving as the ABS self test is carried out at something like 10mph and the ESP system uses the ABS ECU.

If it did come on after driving through a puddle it may be worth removing each wheel one by one and having a good look at the ABS wheel sensor wiring. 
The documentation states if it's a wheel sensor you will have _both ABS and ESP_ light but with databus faults it can be difficult so I would rule out the easy checks first.


----------



## big_nige (Mar 2, 2013)

I'll check the hqaldex wiring too, as i hear these can et a bit crudded up...


----------



## Skeee (Jun 9, 2009)

The Haldex is exposed underneath so definitely worth a check.

Start with all the easy exposed parts first before getting too deeply involved.


----------

