meTTal

As the title suggests, I'm having a very strange issue with my 2000 TT (1.8T, manual) that has boggled even the local mechanics, who have spent more than 6 hours working on it and can't figure out what's wrong.

I'll start at the beginning. About 4 or 5 months ago I started having intermittent problems with the car completely turning itself off when it was put in reverse - the engine, all of the lights, the gauges, the heater: *everything*. When put back into neutral, however, everything would turn back on, except I'd have to manually start the engine again. The car would not start again if left in reverse after it turned off - it would turn over about 3x it's normal speed, and it would continue to turn over without catching. It would always start again (and turn over at the normal speed) when placed in neutral (or any other gear, for that matter), and when I tried to shift into reverse after restarting it would work fine and I'd be off. This only occurred about once a week, and I would drive the car at least twice a day.

The problem has been gradually getting worse, however. At first it would allow me to shift into reverse (without the car turning off) after restarting it the first time. It worsened to the point where I'd have to restart it 2 or 3 times before it finally stayed on and I could move it.

Fast forward to last week (Thursday). The car started fine, but when I put it into reverse it turned off. This happened 4 or 5 times - a new record. After the 5th time, I left it in neutral and waited about 5 mins. When I tried to start it again it did start, but it turned over at the same rapid speed as it did when I tried to start it in reverse. Putting it into reverse caused the car to turn off again. I repeated this 2 or 3 more times afterwards, until finally the car wouldn't even start in neutral, or any gear. I had to get it towed to the local VW dealership (there are no Audi dealers around here, unfortunately).

The VW dealership spent 6 hours trying to figure out what was wrong, but all they could determine was that none of the relays appeared bad, and they found a pinched wire in the center console (near the cigarette lighter). They checked the error codes, and the car came back with 15 of them, ranging from Fuel Injectors on all 4 cylinders and "secondary air inlet valve-N112" with "short-circuit to ground" to "crash signal from airbag control unit" with "implausable signal". They checked the wiring diagram and found that all of these circuits were run by the fuel pump relay. They told me they checked that relay, but they couldn't find anything wrong with it.

When they had finished with the car, they told me that they could get it to start and go into reverse without shutting off, but a lot of the gauges (fuel gauge especially) were working sporadically and the car still wouldn't start in reverse. I told them that I'd take it as is, and when I went to pick it up we went to the car and tried to start it in reverse - it worked perfectly. I turned the car off and tried to start it again, but this time it wouldn't start at all again, in any gear. They tried reading the error codes again, but the car refused to connect to the tool - it was almost as though the car didn't realize it was on or something.

So now I turn to you guys. Have any of you ever experienced anything like this, or have any ideas what could be wrong? 6 hours of labor was not cheap, and I don't want to have them take another 6 hours or more blundering around with the car trying to figure out what's going on with it.

The only modification I've made to the car is adding the OSIR Shift **** and Shift Base ring to it. In order to do that, I had to run a wire from the shift **** to the back of the cigarette lighter and clip the two wires together. The car worked fine after these, but I figured it might be worth mentioning anyway.

Here are all the error codes returned by the car, if it'll help:

15 Trouble code detected?

18010 P1602 035
Power Supply (B+) Terminal 30
Low Voltage
sporadic

18084 P1676 035
Drive by Wire-MIL Circ.
Electrical malfunction in the electrical circuit
sporadic

18098 P1690 035
Malfunction indicator lamp (MIL) -K83-
Electrical malfunction in the electrical circuit
sporadic

17633 P1225 035
Cylinder 1 Fuel injector -N30-
short-circuit to ground
sporadic

17635 P1227 035
Cylinder 3 fuel injector -N32-
short-circuit to ground
sporadic

17636 P1228 035
Cylinder 4 fuel injector -N33-
short-circuit to ground
sporadic

17634 P1226 035
Cylinder 2 fuel injector -N31-
short-circuit to ground
sporadic

17833 P1425 035
Evaporative Emission (EVAP) canister purge regulator valve
short-circuit to ground
sporadic

17955 P1547 035
Wastegate bypass regulator valuve -N75
short-circuit to ground
sporadic

17525 P1117 035
02 Sensor heater circ., bank1-sensor2
short-circuit to ground
sporadic

17876 P1468 035
Evaporative emission (EVAP) canister purge solenoid
short-circuit to ground
sporadic

17843 P1435 035
Secondary Air Injection (AIR) pump relay -J299
short-circuit to ground
sporadic

17829 P1421 035
Secondary air inlet valve-N112
short-circuit to ground
sporadic

17697 P1289 035
Recirculating valve for turbocharger -N249
short-circuit to ground
sporadic

17931 P1523 035
Crash signal from airbag control unit
Implausible signal
sporadic

300ShooTTer

Jeeze, it sounds like it got a virus or something. I think you may have the new record for most jacked up electrical problems.

SparTTan

Wow. If I had to guess I'd say a bad ECU.

TTinCT

sensitive to electrical, i am not surprised....

Everything you have noted, looks like it is electrical to me.....i would start to look at the grounding of the car first off....

to me the basics would be my first couple of steps...
1- Check your negative lead on the battery to and insure it is clean and solid. Also check the ground at the chassis....this is done by following the negative lead off the battery to the chassis.

2- I would check the ECU to insure it is socketed correctly and the leads are CLEAN. If whater has gotten in there, it is possible it could be corroded....

3- If you have not done so...change the temp sensor to the green version....yeah, this seems dumb, but it is the bane of lots of problems....specifically electrical anomalies.

4- On the reverse only/car dying....i would double check and electrical connections near the shift gate. If when the car goes into reverse there is a wire that is grounding there, it could be a problem (however not likely)....


I would start with those and report back.....more than likely it will take a couple of posts/responses to figure this one out...

good luck...

MCPaudiTT - DEFCON 1

is it?

RoberTT-WWCD

can cause all kind of problems. These cars use a lot of electronic on board.

Try this - using a good volt meter and the keys on your pocket, check the battery at the terminals. You are looking for around 12.4v. Anything under 12.2 and you have a bad battery.

If the battery is good, the ECU could be bad.

I looked most of the codes up, and this is the direction it seems to be going.

Hope this helps.

MaxHedrm

I would almost say something that moves when the engine moves from being put in reverse, but that seems unlikely since it won't restart in reverse either.

meTTal

So far those are the two most common theories - either the car isn't grounded properly, or the ECU is bad. The car is still at the VW dealership, but I'm hesitant to call them back and ask them to check these things considering they've already charged me for 6hrs (~$700 worth) of labour and I've got nothing to show for it. If I give them a list of things to check they'll most likely try to charge me even more, and I really don't want to (and can't afford to) pay them any more for nothing.

There's a shop in town that specializes in VW and Audi's, and when I called them they told me they'd never heard of this happening before, but if they couldn't figure out what was going on they wouldn't charge me anything. Unfortunately, they can't take me in until tomorrow.

meTTal

I'm not certain how old the battery is, to be honest. It was in the car when I bought it a little over a year ago. Somehow I don't think it's related to the battery, unless the ground isn't connected to it properly (as was suggested by TTinCT). The car has no problem turning over, and there seems to be plenty of power from the battery.

meTTal

This car has been nothing but trouble since the day I bought it. I've already replaced the steering rack, had a rear lower control arm break off leaving my my axle to fall apart, and now this.

Don't get me wrong, I still love the TT... just falling out of love with *this* TT.