Hi. Never seen this before. Our polo has started accelerating on its own. It has happened 3-4 times in 2 days.

Checked the mat is not in the way. Even did it today 4-5 seconds after releasing accelerator down a hill.

No fault codes on VAG COM. Never seen this before, can anyone shed any light on this problem?

Thanks in advance

does it have cruise control?

No it doesn't. Is there any way of telling if it has been activated in VAG COM? Does it have a separate ecu for cruise or is it controlled by ecu? Maybe getting a false signal?

The fault happened again 4-5 times this morning when cold doing around 55mph foot off the accelerator. Accelerates for 3-4 seconds then shuts off.

Thinking 3 possibilities

Pedal

ECU

Cruise Control issue although not installed.

Any help is much appreciated.

you checked your throttle cable and joins in case its sticking somwhere?

^^^ it doesn't have a throttle cable, it's drive-by-wire on the pd diesels..

no the is no seperate cruise control ecu, it is incorporated into the main ecu. my guess then is that it is a faulty pedal sensor, unfortunately they cost an absoute mint to buy from the dealer

do you have access to vag-com then?

if you going into engine 01, measuring bocks 08, group 54... i think it's the 3rd of 4th field gives you the throttle position at the pedal iirc, if you then go into vag-scope on that group you should be able to make it display the pedal position as a line-graph, then you can rev it a few times to see if it's sticking or whatever...

...erm, from memory i think it's group 54, if it's not right let me know and i'll look it up when i get home

edit: should also be able to see it on group 10... it should show. Maf reading, Barometric Pressure, Boost Pressure, Throttle percentage

Edited 19 May, 201016 yr by SkodaBoy

Just read your last post. I have been logging group 002 today.

I was comparing Load with RPM + Water Temperature.

Something interesting happened, the coolant temp sensor was going crazy and tied in with the acceleration, suddenly made sense in my eyes.

e.g. fluctuating from -14C = +80C overfuelling to compensate. Changed sensor.

Still same problem. I have ordered a pedal from a breakers through fleabay and was meant to be here by now.

Am I reading the incorrect field as the load tied in with pedal movement but I wasn't 100% sure. I will try the group you said to check. I didnt know if load % was the actual pedal reading or load demanded by the engine.

Thanks in advance, this problem is taking over my life as my girlfriend refuses to drive "HERBY" around!!! :)

ha, i knew you would ask that question. i'm not 100% sure of the answer to that.. i'l plug up my lupo tdi in the morning and figure out which way to test it

Very much appreciated.

You have already helped more than my local VW garage. They are clueless. They also won't tell me why my pedal part number has now been revised with a new part number, suspicious. Lets hope the pedal from the breakers turns up today (with new part number) as promised.

Changed pedal, problem persists! Aaaaaaaaargh! please help

Changed:

ECU, same problem

Engine Speed sensor, same problem

Disconnected Speedo, same problem

Any suggestions would be great.

To save everyone re-reading here is where I am to date. Help needed!

I have a polo 1.4tdi 9n MK6 2003

It has been accelerating on its own. After trying new ECU, Pedal, Convenience Unit etc we still could not find problem.

Then I removed the Fuse for the air conditioning system and it behaves as normal. So 100% related to this as been driving without this fuse for months.

Only problem is Aircon does not work and you cannot change temperature unless you insert fuse, then set temperature and again remove.

I have removed heater panel and changed it, still problem persists.

There are 3 ways to stop accelerating on its own.

1. If I remove aircon fuse (then cannot use aircon or heating control)

2. I remove the Aircon/Heater plug as shown. (then heating control aircon does not work and central locking sometimes stops working)

3. Remove Can bus plug into convenience unit (Central locking/alarm plays up)

I am thinking its a problem with can bus signals. Do you suggest next steps to isolate fault? VAG COM thrown no fault codes.

With the 2 can bus wires pictured (Orange/Green & Orange Brown) is there an input into aircon unit that passes though causing problems?

This fault first came about shortly after changing stereo so possible short to can bus bus mistake?

ANY help would be greatly appreciated!!!