Ignition Fault

[Darkelf26]

hi, hope someone can help me this is a wierd fault. whilst driving along the motorway the ignition coil light flashes and I loose power, pressing the accelerator does nothing. I pull to the hard shoulder. Turn off the engine and then restart and the fault is gone. This doesnt happen every time but has happenned now enough for me to start to worry about it.

 

Basically loss of power until car stops moving and engine is switched off and on again.

 

Hope someone can help because I am being quoted some really silly prices for an investigation to find the cause, no garage is willing to commit to what it can be without an exhaustive expensive search.

 

Heres hoping you guru's can help.....

[Darkelf26]

Bit of extra info:

 

Car is 03 LX TDI 1.9

this is the diesel version so I understand that the coil light is also the Engine management light.

Vehicule has done 125K

 

Any help gratefully appreciated.

[gregers]

do your brake lights work??

might be worth checking the brake switch.

look in the faqs for a how too.

[seatkid]

Probably a faulty throttle position sensor. Its a dual potentiometer device and when one disagrees with the other, the ECU gives up, flashes the EM (coil) light, and adopts a fast idle (in my case 1300rpm) with no further control by pedal possible until the ignition is turned off/on.

 

Mine has done this 3 times now in about 5 years (first time was during a dangerous overtaking manouver that could have ended in tradegy).

 

The solution is to either replace the sensor (about £60-£70 IIRC) or have a go at fixing it - one poster claimed he opened it up and cleaned it out - not sure if this was true.

 

I would have thought the fault is logged and viewable on a diagnostic scan e.g. VAGCOM

Edited April 12, 2012 by seatkid

[chrispb123456]

Yep if the glow plug light is flashing a fault code will be logged, scan with Vagcom.

[Mirez]

If you don't have access to VC then where in the south west are you?

[Darkelf26]

Apologies for the late response but shortly after posting this family issues pulled me away from home.

 

I dont have VC and am in Swindon. and the fast idle sounds about right. I will try and see if I can find somewhere in swindon with VC that isnt too expensive.

 

Many thanks for advice.

[Scorpiorefugee]

This happened to me yesterday morning. Loss of power and throttle control - tickover a bit fast about 1200 and a quick restart puts it all back to normal. I immediately remembered Seatkid's post of about 5 years ago and a quick go with the VAGCOM confirmed throttle sensor (P1369 I think) so I'm not going to worry too much unless it happens again. When this was first reported we had a longish discussion on the loonacy of this particular programmed response and there was a lot of bad press for Toyota for a very similar problem resulting in several fatal accidents but that's progress.

[Scorpiorefugee]

Yesterday, I spoke too soon. It happened 7 times in 2 miles this morning so I took the throttle sensor out. Not as bad as it looked, 3 screws and a plug. 5 screws to take the lid off, one of which has a dab of black paint as it is an adjustment seal and It all looked clean but I gave it a good rub over with a clean thumb :-) and after deciding not to rub the tracks over with a soft lead pencil (an old noisy volume control trick) put it back. The tracks are quite low resistance (250 ohms ish) and looked unmarked by the wipers so it would be quite possible for the slightest trace of anything to upset it. 20 miles and no problems and it actually seems smoother to control at low revs, although that could be psychological. I'll report back if it goes again but I checked with the local VW dealer using the 'D' part no. and a new one is special order for £62 + VAT. Edited June 6, 2012 by Scorpiorefugee