Seat Leon 'limp mode'?

Chippy01

Herself told me a wierd tale today.

One of her work colleagues has Seat Leon ('07 she reckons), and for the past couple of days it's been acting up. Symptoms are a loss of power, even though the engine does not cut out.
Every time this happens, she pulls in, switches off the engine, waits a few seconds, restarts and away she goes again.
As you can imagine, this is not the way to go, so this morning she took it to a local mechanic.
Onto the diagnostic and it brought up a fault as a failed brake light bulb.
She was told that the bulb failure is linked to the engine management system, and it's failure was putting the car into some sort of limp mode.
The bulb was changed and the old Seat is back to it's old self again.

This doesn't sound right to me; has anyone else ever heard of this??

toastedpickles

That is.....bizarre to say the least, but i can safely say i've never heard of that until now

Pat Mustard

I'd bring her to an auto-electrician, if I were you, OP.

MuppetCheck

I never had anything like that on my mark 2 Leon. The warning light and bulb out lights are separate. Which bulb is it? They front side lights are known to constantly blow.

Either way take it to someone else for an opinion.

btb

Not unknown, seen it on a skoda fabia I had many years ago,

jca

You sure it wasn't a failed brake light switch? I saw it in a 98 Passat where someone had replaced a stop/tail bulb with a single filament bulb. Every time the lights were turned on the car would lose all power as the ecu thought the brakes were being applied.

Chippy01

jca wrote: »

You sure it wasn't a failed brake light switch? I saw it in a 98 Passat where someone had replaced a stop/tail bulb with a single filament bulb. Every time the lights were turned on the car would lose all power as the ecu thought the brakes were being applied.

It was herself that told me the story.
As far as she knows the car was driving fine, then started acting all wierd, and after the trip to the diagnostic chappy and a replaced brake light bulb, everything is okee-dokee again.

It just struck me as strange that a manufacturer would programme a car to go into limp mode just to highlight a blown brake light bulb, :eek: which got me to wonder if anyone else had come across this.

sham58107

Had the same a few years ago with 09 Passat brake bulb was faulty as result computer tells car something wrong with brakes so safety mode.
Was relieved at fix cost.

jca

Chippy01 wrote: »

It was herself that told me the story.
As far as she knows the car was driving fine, then started acting all wierd, and after the trip to the diagnostic chappy and a replaced brake light bulb, everything is okee-dokee again.

It just struck me as strange that a manufacturer would programme a car to go into limp mode just to highlight a blown brake light bulb, :eek: which got me to wonder if anyone else had come across this.

I don't think you understand what happened. It wasn't a simple blown bulb. It looks like the bulb went faulty and power from the lighting circuit was being fed into the brake light circuit. The ecu detects this power and assumes the brakes are being applied but the accelerator is being pressed it can't work out the conflict and drops everything back to limp mode.

Chippy01

jca wrote: »

I don't think you understand what happened. It wasn't a simple blown bulb. It looks like the bulb went faulty and power from the lighting circuit was being fed into the brake light circuit. The ecu detects this power and assumes the brakes are being applied but the accelerator is being pressed it can't work out the conflict and drops everything back to limp mode.

That explanation makes sense alright.
I just had a chat with herself. Apparantly it was BOTH brake light bulbs that had gone, and the blown bulb(s) was the only fault recorded by the diognostic doo-hickey.
Oh, and that the car is now 100% again now.

jca

Chippy01 wrote: »

That explanation makes sense alright.
I just had a chat with herself. Apparantly it was BOTH brake light bulbs that had gone, and the blown bulb(s) was the only fault recorded by the diognostic doo-hickey.
Oh, and that the car is now 100% again now.

Good stuff. You approached it in the correct manner which always helps. Diagnostic first and work from there.