engine lumpy/hesitant when cold esp light coming on.

[Mark Redman]

Hi there i have a Golf 130 tdi ASZ engine code my problem is when driving the car develops a missfire or hesitantcy this has happenened a couple of times in the last couple of weeks.The fault clears itself very quickly and is then fine the rest of the day.Today things got worse the car started to run lumpy on the motorway,so i slowed down and i observed the esp light had come on. I stopped on the hard shoulder to see if the fault would clear it self but the engine ran lumpy and the esp light didn't go out til i turned the engine off, once restarted the light had gone out and everything was back to normal. This is the first time the esp light has come on with the engine running lumpy sorry to waffle but if anyone has any ideas ?

[kite]

You need to get a fault code read, that will give you a good place to start.

[Crasher]

When read for fault codes it will probably have an electrical fault for number 1 injector stored, if it does have this code, have a new cylinder head wiring harness fitted and this should cure it. The harness will cost about £50 and takes under 2 hours to install.

[Mark Redman]

Hi thanks very much for your replies, i have just been out to the car and read the codes with a hand held scanner. The codes are 16685 (yes u were spot on no 1 cylinder miss fire ) the other code i have is 18074 i dont know what this code means so at the moment it looks like i need cylinder head wiring harness to cure the miss fire any info about the other code would be useful

[Mark Redman]

Hi well Crasher is a top man the other code 18074 confirms cylinder 1 electrical malfunction. I shall be hot footing it to Vw dealer for a loom to fix the fault. One other question is it normal for the esp light to come on as well?Also i don't know if this has any effect on the diagnosis but the car is fitted with a tuning box which has been on the car for about 18 mths or more.

[Crasher]

The thing I don’t understand is why it is nearly always number 1, I have only rarely seen it be another cylinder, doesn’t make sense.

The ESP light will illuminate with these codes due to a power delivery issue so scan the ABS and clear the codes stored.

The tuning box should not have anything to do with it but as it plugs into the head harness I suggest you try the car with the box unplugged just to be certain you are not changing the harness when it is the box at fault.

[Mark Redman]

Hi right i will unplug the tuning box and reset the the engine codes and the abs codes then see what happens tomorrow. Fingers crossed thanks again Crasher

[Mark Redman]

Hello time for an update,thanks to Crasher and his amazing diagnosis i did have to buy a cylinder head wiring harness for the injectors. I fitted it Sunday, bit fiddly but after clearing the fault codes everything seems to be 100% again. Thanks to Crasher