WTF is going on with my GF's Ibiza???

saint_david

Guest
Where do I start. Apologies beforehand for the long post but its a long, confusing story.

My girlfriend has a '53 Ibiza 1.2. In January of this year whilst driving normally the EPC light came on the dashboard and the engine wouldn't idle properly. We took it in to the local garage who plugged it in and told us the brake light switch had gone and needed replacing. This was done and the problem appeared to have been resolved - brake lights were working and the EPC light had gone off.

Shortly after getting the car back, the engine management light came came on and again the car wouldn't idle properly. Back to the garage it went, this time apparently both coils had gone and so these were replaced. Once again the problem appeared to have been resolved.

Fast forward a couple of days and the EPC light is back on. Back to the garage who plug it in and tell us it needs a new air flow sensor (I *think* this is what they said, the gf can't remember exactly). Job done, car runs ok until...

...the EPC light makes another appearance a few days later. By this point the GF wants to push the car off a cliff. She reported it occurring at traffic lights when the car was stationary and when it came on the revs bounced up and down repeatedly. This time however, the light would disappear after the engine was switched off. It would spring up intermittently usually when idling at traffic lights. We took it back to the garage who couldn't get the EPC light to come on and advised us to take it to a main dealer or SEAT specialist who might have more luck. We took it to a seat specialist who managed to get the light to come on and told us it was a problem with the throttle body. They advised us to have the throttle body cleaned, which we did, and the problem seemed to have been sorted. Guess what? It wasn't.

The past few days the EPC light has been coming on when the cars been idling and the revs have been all over the place. The second garage we took it to have said the throttle body probably needs replacingwhich is what we're about to take it in to get done. Today though I noticed the car idles normally UNTIL you press the brake pedal about 4 - 5 times, at which point the EPClight comes on and we start having fun with the revs again. Turn the car off and its back to normal, until you do the trick with the brake pedal. Also, even though the latest problem has been happening for over a week, when I did the brake pedal trick today the engine management light decided to come on and has stayed on. Fantastic!

So before we spend a small fortune getting the throttle body replaced can anyone suggest what else (if anything) might be causing the current issue? Why would pressing the brake pedal ultimately screw around with the throttle body? Could the original problem regarding the brake light switch somehow be causing any of this (due to the fact the current issue occurs when the brake pedal is pushed) ?

Thanks for reading - any help would be MUCH appreciated.
 

ss55eat

Active Member
Nov 28, 2008
53
0
The brake pedal switch is used by the engine ECU to detect when you are braking and it cuts the fuel off. A fault on the switch is seen as a safety issue by the ECU (if electronic throttle pedal fails at full throttle it knows there is a problem as you are frantically trying to brake!!!!). This is why the EPC light comes on for a brake switch problem. Try your 4-5 times braking with someone watching the rear brake lights and make sure they are coming on OK. If not this points to another bad (or incorrectly fitted?) switch.

Another possibility is that there is something wrong with the brake servo and it's leaking air back into engine. This would look like a partially open throttle and might confuse the ECU's control of the throttle body? Also suspicious that you had an airflow sensor fault reported - again an air leak might possibly cause that?

Just so you feel better, I've had the standard brake light switch failure as well, and also took the car back about 5 times for the airbag fault light coming on. Luckily it was all still under warranty but I was tempted to push the car off the same cliff....
 

saint_david

Guest
The brake pedal switch is used by the engine ECU to detect when you are braking and it cuts the fuel off. A fault on the switch is seen as a safety issue by the ECU (if electronic throttle pedal fails at full throttle it knows there is a problem as you are frantically trying to brake!!!!). This is why the EPC light comes on for a brake switch problem. Try your 4-5 times braking with someone watching the rear brake lights and make sure they are coming on OK. If not this points to another bad (or incorrectly fitted?) switch.

Another possibility is that there is something wrong with the brake servo and it's leaking air back into engine. This would look like a partially open throttle and might confuse the ECU's control of the throttle body? Also suspicious that you had an airflow sensor fault reported - again an air leak might possibly cause that?

Just so you feel better, I've had the standard brake light switch failure as well, and also took the car back about 5 times for the airbag fault light coming on. Luckily it was all still under warranty but I was tempted to push the car off the same cliff....

Thanks for the info, VERY much appreciated :)
 

josh263uk

Waiting for the sunshine!
Aug 13, 2007
365
15
Saarland Germany
I had my EPC light and engine management light on the other day, when to the garage and they diagnosed a faulty accelorater sender unit, its been replaced and no issues. Maybe an area to explore.
 

Stanislav

Active Member
Nov 30, 2009
52
0
Finland
I had my EPC light and engine management light on the other day, when to the garage and they diagnosed a faulty accelorater sender unit, its been replaced and no issues. Maybe an area to explore.

I have the same issue right now, how much did u pay for replacement?
 

Stanislav

Active Member
Nov 30, 2009
52
0
Finland
Yes i know that! But I dont have warranty and I dont think I got problems with accelerator! But we will see I book the time on monday at the garage! Will tell you what did I have!
 

Stanislav

Active Member
Nov 30, 2009
52
0
Finland
Any news?

Yes sir!!! Sorry for a slow reply! I went to the garage and they said the RPC had an error with the code so the light on a dash was on, so the reprogram and put the new code!

it cost me 56 euros coz Im in Finland so in pounds will be arround 45 quid!
 
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