56 plate Ibiza epc light problem.

[A.J.M]

My girlfriends Ibiza has recently started to flash it's epc warning light while she is driving, it cuts acceleration and has left her in a few unwanted situations on the motorway because of it.
Car has been taken back to Arnold Clark dealer 3 times in 3 weeks and they have replaced an accelerator switch but can't find the problem.

Her warrenty runs out next month so would like to know what's wrong and what to get fixed as the dealer seems useless at fixing it!

Any ideas for me to pass on to her to tell the dealer? Will get me extra call of duty game time and extra sex if I can get it figured out.

[Tame Technician]

Not 100% sure about the Ibiza, but had this issue on 2004-2009 A3's a few times (probably the same technology)

What happening for definite is the cars ABS system falsely thinks its wheel spinning so the traction control strategy is being deployed although its not required, so the power is eased off and the ESP light flashed. It wont log any helpful fault codes for the technicians because it thinks its working properly, again the light flashing means its doing its job, if it thought there was a fault the light would come on and stay on instead of flash.

How to fix it......... We it will be a sensor issue making the control module think its wheel spinning, so most likely a wheel speed sensor or wheel speed sensor harness.
However, A3’s we had doing this were fixed by replacing the rear wheel bearings.
Let we explain.
First time we saw this, we replaced all 4 wheel speed sensors under warranty and was still the same, we tried new harnesses , still the same. Then I replaced both the rear wheel bearings, car fixed.
The wheel bearings (only on the rear of the car) have a special magnetised coating on the inside face that the ABS sensor pics up on, somehow this coating did not have quite enough of a magnetic effect on the ABS sensor and every now and then from time to time would result in the ABS control module mis-reading the wheel speed, so if it sees the front wheels going round at 20 and the rear wheels staying still or moving slower, it think the car is wheel spinning.

[Cupramax]

EPC light has nothing to do with ESP poster above. EPC is the electronic potentiometer control warning light (electronic throttle pedal to you and me) so it clearly thinks there is a throttle issue somewhere. When you say the dealer changed the switch what do you mean, did they change the entire throttle pedal unit? Has the Ibiza got a floor mounted throttle or is it in the pedal box behind the dash?

[Tame Technician]

OMG so sorry mis-read it as ESP, and the symptoms matched. what a numpty, my bad

EPC is indeed engine management related not ABS/ESP, humble abbologies.

I've got man flu my brains not working........excuses excese etc.

[A.J.M]

Cupramax said:

EPC light has nothing to do with ESP poster above. EPC is the electronic potentiometer control warning light (electronic throttle pedal to you and me) so it clearly thinks there is a throttle issue somewhere. When you say the dealer changed the switch what do you mean, did they change the entire throttle pedal unit? Has the Ibiza got a floor mounted throttle or is it in the pedal box behind the dash?

Its a basic 1.4 with wheel trims to would think its a pedal box behind the dash?

She says they changed a switch but not the full throttle pedal unit, would changing that help it?

Arnold clarks attitude is its a known problem but if it happens when the warrenty runs out then she will be charged for work on it. So would like it solved before they start any crap.

[Cupramax]

If its still doing it, what they've changed is obviously not the cause. The brake light switch can cause problems and it may be this that they've replaced. Ask exactly what part they replaced, you should have got a report of the warranty work and any parts fitted.

[A.J.M]

Cupramax said:

If its still doing it, what they've changed is obviously not the cause. The brake light switch can cause problems and it may be this that they've replaced. Ask exactly what part they replaced, you should have got a report of the warranty work and any parts fitted.

I'll call her tonight and find out what exactly was changed. I'll let you know when i know as it would be good to get this sorted. She really needs the car for going to uni/school placements and she never got a courtesy car on 2 occasions it went in to get looked at.

Do you know what the usual problem parts are that cause this so i can pass it on so they get looked at.

Thanks for you help so far mate

[Cupramax]

Well, the first place to look would be for the dealer to plug in their diagnostics box and check any fault codes, I guess they've done this and found a corresponding fault for the brake light switch. To be honest if it was me I'd change the throttle pedal module next and see if that sorts it, with these sort of faults its a case of changing one thing at a time methodically until you find whats causing it.