Worrying Behaviour!

[steamship]

Was out today for a 50 mile trip. Country roads mainly, so never got about 50mph. Both traction control and ABS lights came on again (as mentioned in another thread), but this time stayed on for around 30 miles (previously only for a few seconds).

More to the point, experienced two other issues which has me seriously worried. The first is a small thump when putting the car into Drive. It doesn't happen in any other gear.

The second was a stall. Was driving uphill towards a roundabout and just eased up on the accelerator. Was doing around 10mph as I reached the roundabout, which by now was clear, and I started to accelerate. Got a couple of car lengths and the car died. Put in Neutral, restarted, into Drive, and away again.

When I got home, I ran a scan on it, and have included the relevant bits below.

-------------------------------------------------------------------------------
Address 01: Engine Labels: None
Part No: 4D0 907 558 AB
Component: 3.7L V8/5V G 0002
Coding: 11753
Shop #: WSC 23143
VCID: 6DDBD76D278ADF1
WAUZZZ4D92N002072 AUZ7Z0A1855153

10 Faults Found:
17521 - Oxygen (Lambda) Sensor; B1 S1
P1113 - 35-10 - Internal Resistance too High - Intermittent
17831 - Secondary Air Injection System; Bank 1
P1423 - 35-00 - Insufficient Flow
17819 - Secondary Air Injection System; Bank 2
P1411 - 35-00 - Insufficient Flow
17536 - Fuel Trim; Bank 1 (Mult)
P1128 - 35-10 - System too Lean - Intermittent
17530 - Oxygen (Lambda) Sensor Heating; B2 S2
P1122 - 35-00 - Open Circuit
17548 - Oxygen (Lambda) Sensor; B2 S2
P1140 - 35-00 - Internal Resistance too High
17538 - Fuel Trim; Bank 2 (Mult)
P1130 - 35-10 - System too Lean - Intermittent
16485 - Mass Air Flow Sensor (G70)
P0101 - 35-00 - Implausible Signal
17545 - Fuel Trim: Bank 1 (Add)
P1137 - 35-00 - System too Rich
17547 - Fuel Trim: Bank 2 (Add)
P1139 - 35-00 - System too Rich
Readiness: 0000 0001

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4D0 907 389 E
Component: ABS/ESP allrad D56
Coding: 08397
Shop #: WSC 02313
VCID: 31630B1DFB327B1

2 Faults Found:
01119 - Gear Recognition Signal
35-10 - - - Intermittent
18265 - Load Signal
P1857 - 35-00 - Error Message from ECU

-------------------------------------------------------------------------------
Address 02: Auto Trans Labels: 01V-927-156.lbl
Part No: 4D0 927 156 DT
Component: AG5 01V 3.7l5V RdW 1920
Coding: 00001
Shop #: WSC 00000
VCID: 7EF9E0217AEC549

1 Fault Found:
18265 - Load Signal
P1857 - 35-00 - Error Message from ECU

End ---------------------------------------------------------------------

I should point out that the car runs on LPG as well. I cleared the codes and the rescan was clear.

I haven't taken the car out for a drive, but just moving it in the drive, there isn't any thump anymore. The traction control and ESP lights have also gone out.

Now, I've been reading through some other posts on similar symptoms and error codes, and none of it makes for good reading.

I'm hoping that all the engine ones are as a result of a faulty thermostat having an effect on how it runs on LPG, and throwing up those errors. They may also be accountable for the stall. I'm buying all the necessary parts for getting the belts done, so will be getting the water pump and thermostat done as well.

The question is, what could be causing the 'thump', which disappears when the codes were cleared? I'm hoping that it isn't the gearbox, as I can't afford a job like that.

[ainarssems]

Your lambda sensor heating is not working, secondary air injection might not be working but the more important issue and first to address is MAF. Could be that MAF is just dirty or bad connection in wiring/connectors but more likely that you will need new MAF. You really want it sorted because if MAF readings are wrong then reported engine load values will be incorrect and can cause damage to gearbox in long term which equals big bill.

[PsYcHe]

As above.. MAF can cause all manner of horribleness with an engine and auto box, it should be priority 1 and then see what else is still around after that as the feedback loops could get all out of kilter.

[steamship]

Lambda sensors replaced in October when I got the car serviced.

The LPG people had the MAF sensor out and cleaned back in December when I had it up with them. Can't imagine how it could get that dirty that quick.

Is there any way to check with VCDS if the MAF is working properly?

[PsYcHe]

check the ross-tech website, but there is a guide somewhere to test the MAF. Not beyond the realms of possibility it's not working properly.

Does the car behave properly on petrol?

[Bandycoot]

I've been getting pretty much the same problem with my D2 S8. Since October my ABS and traction control lights would come on and sometimes these would be accompanied by the ESP light coming on. When this happened the car just would not accelerate, well it would but very slowly. Also, there would be and intermittent misfire at times. The first thing I did was to change the ABS unit. No luck. So I purchased VCDS and then recoded the it. No luck. I then pulled the fault codes and mine were pretty much the same as yours.

I tried throttle body adaptions many times. Still no luck. I took the fault code readout to the local Audi dealer and they told me it was all down to an air leak somewhere in the system. I found a split in the throttle body elbow so this was changed. No luck. I noticed two of the throttle body to manifold bolt holes had stripped so I had these helicoiled. Actually, the machine shop drilled out the holes inserted brass inserts then drilled and tapped the inserts. Except one of them must have been slightly proud so they filed it flat but created a grove in the surface in the process. (But it wasn't their fault. They said so. This is Dubai and crap workmanship is perfectly normal.)

Still no luck. Convinced it was the throttle body I had Carl at A8Parts send me out a replacement. Good for two days then back to same problems. Now convinced it was the MAF I changed this. No luck.

I found a split in the air box to inlet pipe rubber elbow and this was replaced along with the two small rubber joints in the fuel regulator to manifold pipe. So far we have success. The annoying misfire has happened a couple of times and the fault codes have been the same both times; throttle body out of adaption and a MAF fault, which is interesting as it's new. The ABS and traction control lights now longer illuminate so this misfire I think is down to a air leak and I believe its where the brain dead machinist filed a grove in the inlet manifold. Sorting that out could be interesting

My advice is to do a thorough check of the air system and check for air leaks. Hopefully you can sort the problem out without having to go through the pain that I have.

Cheers

Steve

[steamship]

So had the car with the mechanic getting the belts, water pump, thermostat and the other gubbings changed. Also fitted a brand new MAF sensor and an ABS pump and controller. Also replaced some of the vacuum hoses at the front as one in particular had been wedged in and severely damaged.

Had the codes cleared, but after a short (15 mile) run today, it's still lighting up the traction control and ESP lights on the dash. They come on for about three seconds and then go out. It repeats this about every 10 minutes and then stay on. When both lights are on, this is when I sometimes experience a stall. This is what a scan showed this evening:

-------------------------------------------------------------------------------
Address 01: Engine Labels: None
Part No: 4D0 907 558 AB
Component: 3.7L V8/5V G 0002
Coding: 11753
Shop #: WSC 23143
VCID: 6DDBD76D278ADF1
WAUZZZ4D92N002072 AUZ7Z0A1855153

3 Faults Found:
17530 - Oxygen (Lambda) Sensor Heating; B2 S2
P1122 - 35-00 - Open Circuit
17548 - Oxygen (Lambda) Sensor; B2 S2
P1140 - 35-00 - Internal Resistance too High
17521 - Oxygen (Lambda) Sensor; B1 S1
P1113 - 35-10 - Internal Resistance too High - Intermittent
Readiness: 0010 1101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8D0-907-389.lbl
Part No: 4D0 907 389 E
Component: ABS/ESP allrad D56
Coding: 08397
Shop #: WSC 02313
VCID: 31630B1DFB327B1

1 Fault Found:
01435 - Brake Pressure Sensor 1 (G201)
48-00 - Supply Voltage

-------------------------------------------------------------------------------

Everything else is clear.

Mechanic said lambda sensors were working fine, so will need to go back to him on this.

Have done the usual Google search for the ABS code, but can't find anything of worth.

My main concern is that the car is going for its MOT on Thursday and I really need it sorted before then.

Any suggestions as to what else could be causing the issue?

[ainarssems]

Regarding to lambda sensors think of as 2 parts- the sensor itself and the heater for it. The fault codes are for the heater part. Lambda sensors need to heat up before starting to work, they do it from exhaust gasses but pretty much any half modern lambda sensor also has electrical heating element within which helps it warm up faster. If the heating part is not working it only takes longer on cold starts before the sensor starts working say 2 minutes instead of 20 seconds. I would not loose sleep about it.

[steamship]

Just an update on the warning lights. Went on a 70 mile trip yesterday. Since I was out longer, I got to see the behaviour of the warning lights better.

I get the two warning lights coming on for a few seconds and then going out. As before it repeats this behaviour about three times. On the next instance, the lights stay on for four minutes and then go out. They stay out for about ten minutes, and then repeat the sequence.

I've done a Google search on the error code:

01435 - Brake Pressure Sensor 1 (G201)
48-00 - Supply Voltage

but haven't found anything worthwhile, and time is running out.

[ainarssems]

I would be looking at the sensor itself, wiring and ABS/ESP ECU.

I see you did not have this code before ABS pump/ECU swap so that would probably be my first guess.