Traction control light
Q About a week ago, when reversing my 2012 SEAT Ibiza
1.2 TSI manual petrol, the traction control light started flashing. There was no wheel spin and the revs didn’t go above 2000. This happened every time I reversed for the next two days and, since then, it has also occurred when slowing down and very occasionally when changing up a gear.
There is no sign of a misfire when accelerating or decelerating. The only time the engine runs roughly is when reversing, however I can’t tell if this is an actual misfire or the ECU attempting to control what it thinks is a problem. The engine also runs fine at idle, and when it is stationery and revved out of gear. When decelerating, the traction control light comes on most often when slowing down in a lower gear – 2nd/3rd – or when the revs are slightly higher – above 2500 – but it is not entirely consistent. Most of the time, the light goes off after around a second but, when coming off a dual carriageway, the light will stay on for around 4 or 5 seconds as I slow gradually from 70mph to a stop – or start accelerating again.
I have a basic code reader at home which shows ‘P0352 (Ignition coil B primary/secondary circuit)’. I have taken it to a local auto electrician with specialist computers for VAG cars and they had similar read-outs (I’ve attached some print-outs). They switched the existing spark plugs and leads between cylinders, but it still showed a fault on cylinder 2. On their recommendation, I have also switched the ignition coil, but this made no difference. Neither did a new PCV, which I replaced as I noticed it had broken when changing the coil. I have also checked the vacuum lines and there are no apparent issues. Aaron Guy
A As changing the spark plug and the coil pack has not affected the problem, this seems to confirm that the fault lies within the wiring loom. The code ‘P0352’ indicates that there is a primary or secondary circuit malfunction – in your case, this appears to be a primary circuit malfunction in the feed to the coil pack. This would also account for the error code ‘P1358 Ignition coil/amplifier, cylinder 2 - open circuit’ as noted on the auto electrician’s sheet. The fault may be in the connecting plug or a point further along the loom, so I would advise checking the loom for continuity. One point made by Autodata is that there is a common fault caused by the loom being damaged by the action of the wiper motor, so this may be a good place to start looking.
It’s also possible there’s a broken wire within a section of loom that is more prone to movement from the engine when the vehicle is reversing or slowing down, so when looking for a break in the loom I would check any such area first. It may be necessary to remove the outer binding tape to expose the wires and, if so, these need to be taped up afterwards.
The connection between the traction control light and the engine codes may also indicate an engine control module fault. In this case, the first check would be ensure the connecting plug terminals are clean, dry and free from any corrosion.
After carrying out the checks above, if nothing has been resolved it may be an idea to send the ECU off for testing, to either ecutesting.com or bba-reman.com