2004 TT Roadster ABS ESP lights on - ABS pump tested and OK, what next?

[volkswizard]

Hi,

I have just bought a 2004 TT Roadster, one of the first with 2WD and AUM coded 150 bhp engine.

The ABS and ESP lights are constantly on and this fault is stored in the engine ECU.

18057 - Powertrain Data Bus: Missing Message from ABS Controller
P1649 - 35-00 - -

Also I can't communicate with the ABS controller at all with VCDS.

I have checked all fuses including those on battery and no joy.
This all pointed to a failed ABS pump though I was a bit suspicious as the part number of this pump rarely comes up on the remanufacturer web sites. I sent it to BBA Reman and they returned it after tests said it was fine.

Car has done 107000 miles with 1 lady owner and appears to have never been in any accidents that could have messed wiring up etc.

Can anybody help?
The only weird thing is that there is no stereo fitted but I'd be surprised if this affected the CAN in this way unless anyone thinks otherwise...?

Any help much appreciated
Andrew

[towcestervag]

check fuses on battery
check live to abs unit ive had fuse holder burn out

[Crasher]

I have had this many times with the plug behind the battery up to the battery fuse box being disconnected. Also as tow says, it is common for the fuse holder to melt.

[volkswizard]

Thanks for the replies

I have checked the fuse holders and they all look fine.

There is a plug with 3 wires that plugs into the offside of the fuseholder on the top of the battery, I have checked this and it's secure, is there another connection hidden away that you are referring to Crasher?

[Crasher]

There is a connector over the back of the battery between the battery and the air box running down the side of the main wiring feeds, I often see these with broken retaining clips after a battery change and so the confection comes free but it often looks OK, make sure it is pushed up tight.

[volkswizard]

There is a connector over the back of the battery between the battery and the air box running down the side of the main wiring feeds, I often see these with broken retaining clips after a battery change and so the confection comes free but it often looks OK, make sure it is pushed up tight.

Thanks again Crasher.
Not with car at the moment but when I checked the connections on top of the battery I followed all the cables go into black plastic trunking that goes under the airbox, is the break usually in there or is it visible?
I should point out that the car appears to have its original battery.

[Crasher]

It is at the side of the cables.

[volkswizard]

checked that Crasher and looks fine.

What about dead MAF causing lights to come?

When the car was first scanned it was complete but the airbox and MAF aren't attached at the mo to allow access to ABS pump.

[volkswizard]

Right have fitted a new MAF, no difference.
Fitted a new battery just in case we had voltage issues, no difference.
Checked the wiring at the back of battery, looks perfect inc all fuses and their holders on top of battery.
Running out of ideas now, possibly some wiring somewhere?

[Crasher]

You need a wiring diagram and then spend some time checking the ABS power and comms wiring.

[volkswizard]

I have a wiring diagram from ELSA, it's not a huge run from pump to ECU so will check that.
I did clean up the earth point on nearside near battery which were a bit corroded but no difference.
If anything I am going to learn a lot from all this.
And I will make sure I post the solution!

[volkswizard]

15333Good news, fixed.
Stripped the tape off at the ABS pump plug so I could see which pole the power supply wires from the battery went and continuity tested them.
Found the red (not red/green) wire failed the test.
Tapped 12v into it near the pump end and bingo!
Finding the break was easy.
I suspected the area at the back of the battery as the loom takes a 90% turn as it reaches the chassis and I could see some green corrosion.
Stripped out battery tray and as I wiggled the loom in the area of the corrosion there it was, gone right though and only held together by a thread of insulation!
So thanks to everyone who responded, this forum is great is the only place I'd bother posting these days:approve:

[Crasher]

I have never seen failure that but I was convinced it was the power feed which is why I was obsessing over the battery plug.

[volkswizard]

Crasher, I was inspired by your (I suspect legendary) 2006 thread on here about another TT that had a wire break hidden away somewhere ;)