Seat Leon mk3 brake light sensor short-circuit

Kissanpentu

Active Member
Dec 28, 2018
2
0
Hi all,
First off, I'm new on this forum so please don't crucify me for doing something stupid.

I have a 2014 Leon that has been acting up for about six months, the problems started with the start-stop system malfunctioning sometimes (wouldn't stop at red lights). That has now stopped working altogether (Start-stop error "Power consumption too high"): the car won't start using the key, but it will start on neutral by switching ignition on and then pressing the clutch. I have also noticed that the brake lights are sometimes always on, even though the brake pedal isn't pressed. The newest addition is the absence of cruise control.
At first I thought the Start-stop problems were due to a bad battery or a faulty neutral position sensor, but after reading the fault code memory through OBD I had to rethink my theories.
The fault codes are something along these lines (translated on the fly):
-Particulate filter pressure difference sensor cyl. row 1 (Unlogical signal)
-Fuel injection controller control "PEM" (ground fault)
-Brake light sensor (ground fault)
-Glow controller (fault in the circuit)
-Fuel cut-off valve (breakage)
-Fuel pressure control valve (breakage)
-Ignition switch circuit (short-circuit, positive wire)
-Fuel pressure control valve (ground fault)
-Airbag controller (Unlogical signal)
-Front airbag collision sensor, driver side (Unlogical signal)

My question to all of you mk3 owners would be that, have you had any similar problems (or error codes) to these and could all of these problems be the result of the brake pedal sensor wire ground-fault? I can't believe that the car could have had so many part breakdowns on different systems.

Also if anyone can provide me with a wiring diagram that shows how the ignition switch and the brake pad sensor are connected together, it would be greatly appreciated.
 
Last edited:

Walone

Active Member
Feb 10, 2016
1,044
225
Near Heathrow
With regard to the start/stop not working I would suggest giving the battery a good charge at least 12 hrs, make sure the negative lead of the charger is connected to the chassis earth not the battery neg terminal. I would assume your car is still under warranty so I suggest a visit to the dealer for the faults.
 

Kissanpentu

Active Member
Dec 28, 2018
2
0
Hi and thanks for the prompt answer, I had miswrote the model year by accident. It's a 2014 model, so the warranty is unfortunately void. I'll try charging the battery, but I don't think it'll solve all of the problems. The car worked just fine the other day, after it spent some time in a warm garage, which made debugging the problems with a repair shop a pain.. The ignition switch was changed but it didn't solve the problems either.

With regard to the start/stop not working I would suggest giving the battery a good charge at least 12 hrs, make sure the negative lead of the charger is connected to the chassis earth not the battery neg terminal. I would assume your car is still under warranty so I suggest a visit to the dealer for the faults.
 
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