PRNDS + Traction-control warning light

[mark antony]

A tale of self-inflicted woe!

 

I was in the process of bringing a 08 automatic elegance back off sorn, and as pre-MOT prep I wanted to clean up the rust that had developed on the front disks. Mindful that you should drive direct to the MOT centre, I came up with the bright (now proven stupid) idea of lifting the front of the car and driving the wheels, so to brake and clean the disks. 

 

Started ok, but as soon as I put it drive the traction-control warning light came. Stopped after about 30 secs, but on lowering the car, a full safely override has come on with the full set of PRNDS light flashing at me, and the car turning over but not tempting to fire.

 

Once or twice I have  managed to clear the faults with a cheap code reader, and under those circumstances, the car drives fine, and will restart if left for less than 5 mins. After that, it goes back into lock-down mode.

 

Any advice to re-balance my stupidity?

 

[AGFalco]

You can try these:-

 

Key out of the car with the windows up.

Disconnect the battery, negative first, positive second and leave for 30 minutes.

Reconnect the battery, positive first, negative second.

 

Or clear the fault code with a better code reader?

 

Thanks AG Falco

[mark antony]

1 hour ago, AGFalco said:

You can try these:-

 

Key out of the car with the windows up.

Disconnect the battery, negative first, positive second and leave for 30 minutes.

Reconnect the battery, positive first, negative second.

 

Or clear the fault code with a better code reader?

 

Thanks AG Falco

Thanks, I'll give this a try. One thing I perhaps should have added is that the cooling fans come on as soon as you turn the ignition. This predates the traction-control warning issue, but not sure if there's any relevance to this fact.

Edited 13 October, 2019 by mark antony
spelling

[chrisund123]

Got a VCDS auto scan?

[mark antony]

2 hours ago, chrisund123 said:

Got a VCDS auto scan?

Haven't had a full VCDS scan done yet, all I've got direct access to is a cheap ebay code reader with an 'erase' option. The scan clears the lights for an instance, then the traction symbol comes back on with the flashing PRNDS lights.

[mark antony]

Update, in that the car keeps returning to 'flashing PRNDS' status. At that point it cranks, but doesn't fire.

 

I can clear using a borrowed  VCDS, and at that point it will fire and indeed drive normally. As long as I don't switch off for more than 2 mins, or lock the car, everything is fine but after that, back to PRNDS status.

 

Background is that the car has been stood for 2 years, with dead flat battery. I charged it, but must admit to jump lead starting a couple of times. 

 

My thoughts a the moment

• Is it likely that I've wiped the ECU?
• If so, can it be reprogrammed.
• Or am I in big trouble!?
• Any VCDS experts on the Wirral who could advise/help?

[mark antony]

A google search would suggest

 

Possible Causes

• Blown fuse for control module
• Wiring Harness issue
• Failed control module

Possible Solutions

• Inspect wiring and terminals for CAN BUS between control modules.

 

http://wiki.ross-tech.com/wiki/index.php/18258/P1850#Possible_Causes

 

Any thoughts on those? And is this something that can be fixed?

 

I am mindful that google knowledge is a double edged sward, as I also saw reference to it being a rear abs sensor, and this brings be full circle as that's were the problems started, when I put the car into drive with the two front wheels off the ground. That triggered the traction, and I've had nothing but problems since!

Edited 20 October, 2019 by mark antony

[mark antony]

As a measure of my desperation/exasperation with the flashing PRNDS status that I've taken to 'bump' this call/cry for help!

 

Am I unique in experiencing these symptoms?

 

The annoying/confusing thing is that the car drives perfectly once you've overridden the code via VCDS, which would suggest that the 'bits' work, but they're not communicating to each other.

 

As you can gather, any help or advice would be truly appreciated.

[langers2k]

The picture you took of the VCDS autoscan is somewhat confusing.

 

The chassis type is 1U which is a MK1 Octavia yet the DSG part number appears to match a MK2 (1Z chassis). I assume the incorrect selection is what prevented the engine ECU appearing above the DSG too.

 

At this point, I'd suggest you do a full autoscan and leave the chassis type as 'auto select' or similar.

 

Once that's done, post the full autoscan rather than a blurry picture. You can either use the save button and attach the resulting txt file, or the copy button and paste the text into a forum post. Both options are much better than taking pictures...

[mark antony]

Langers2k,

 

Thanks for mainlining an oversight to this issue, as it's well beyond my direct understanding.

 

On that basis, the car is now with local VAG independent specialist WCC, based in Neston on the Wirral. They ran a VCDS check and they've told me that the same 18258 - P1850 code is showing against the correct car type. A number of ABS related codes also showed up. The oddity, as reported to me me is that the VCDS wouldn't connect to the engine, they got around that by using the auto scan route, and that enabled them to get to the codes and clear them.

 

But the same problem reappears in that it immobilises again as soon as you stop the car. The second oddity is that when the car is running, there is absolutely no problem with it, mechanically it drives fine, changes gears when it should and stops fine. Some corrupted messages are getting back to the controlling system.

 

I see that you're ODIS enabled, and this is the next step. They'e going to run that and see what shows up. 

 

Do you have any guesses as to what the issue might be?

 

Thanks again for your support, it is appreciated as I sit here, so near yet so far from getting a good car back onto the road.

 

 

[langers2k]

At a guess, some module on the powertrain CAN-bus is unhappy and that's causing the issues. Hard to say without a full autoscan I'm afraid.

 

Given the difficulty accessing the ECU, it's probably a good place to start. At least checking it's connectors are clean and in good condition etc.

[mark antony]

They're due to run the checks on Friday and we'll see where to go from there.

 

They seem very competent, but wondered if there's anything specific that I should ask them to check?

 

Is the power train canbus easy to get at?

[mark antony]

Intermediate update in that the code readings identified that the ECU wasn't speaking to to modules that it should. The garage has taken the battery tray out to get to the ECU ................. and found a mouse nest, with evidence of chewed wires.  Background is that the car has stood for 4 years.

 

Not sure on the next steps, but an unusual case to resolve!

 

 

[langers2k]

That would certainly do it...

 

Depending on the level of damage, it might be possible to repair the loom 😕

[TheClient]

Mouse nest.. every ecu's best friend!! 

[mark antony]

Update, in still stuck in limbo with this fault.

 

In a step by step review:

• The mouse issue was a red herring, in that there was mouse material, but no damage caused.
• The ECU was sent away, and first returned as 'no fault'
• Fair play to the garage, in that they used a temporary donor ECU and found that this took the PRNDS problem away
• ECU sent away to another workshop, and returned
• ECU fitted - PRNDS issue gone and car drives perfectly
• BUT - at this point the seatbelt warning light came on, and when hooked up to code reader, it suggested that it wouldn't connect to the seatbelt circuit so couldn't be removed.

ECU returned for a third time, and MIGHT come back fine, but wondered if anyone had thoughts on how to sort out final seatbelt issue (unfortunately haven't got codes)

 

Thanks for your interest

 

[KenONeill]

12 minutes ago, mark antony said:

the seatbelt warning light came on,

FWIW, anything I've driven with a SWL on it (multiple makes, some pre-CANBus) will drive normally with the SWL (and buzzer if fitted) active.

[mark antony]

30 minutes ago, KenONeill said:

FWIW, anything I've driven with a SWL on it (multiple makes, some pre-CANBus) will drive normally with the SWL (and buzzer if fitted) active.

Apologising for my ignorance , but what does SWL stand for?

[KenONeill]

46 minutes ago, mark antony said:

Apologising for my ignorance , but what does SWL stand for?

Seatbelt Warning Light.

[mark antony]

1 hour ago, KenONeill said:

FWIW, anything I've driven with a SWL on it (multiple makes, some pre-CANBus) will drive normally with the SWL (and buzzer if fitted) active.

 

You're absolutely right with your observation in that it drives perfectly; but need the SWL out for the MOT test.

[J.R.]

On 20/10/2019 at 18:37, mark antony said:

 

Background is that the car has been stood for 2 years, with dead flat battery. I charged it, but must admit to jump lead starting a couple of times. 

 

 

Anything less than a perfect battery will cause no end of ECU and fault code problems, replacing it with a new one would be my very first step.

 

My new expensive Bosch was never that good from the start, its resting voltage was always 0.5 volt less than the 10 year old Varta that it replaced, then I left sidelights on all night and tried and failed to restart it like you, loads of fault codes to clear after charging it.

 

Now despite the fact that it will always start the carin 1/4 turn the voltage drop will light up the dash like a christmas tree, I have an LCD voltage monitor, if the voltage is down to 12.0 volt before I get in (courtesy lights and canbus wake up will drop it further) I know that it will start but if I dont wait till the glowplug light goes out and the voltage rises to 11.8v before cranking it will throw up all the codes again.

 

Repace he battery or borrow a known good one, not just good enough to start but one that will do so with minimum volt drop.