Octavia VRS rear fog light not working and it's not the bulb ...

[ChrisBarnes]

I have a problem with my 2009 1Z Octavia TDI VRS left rear fog light that is driving me nuts.

I had a bulb failure warning a few months back for the left rear fog light.  No problem, I'll replace it.  On inspection the bulb was ok.  I removed the left boot internal trim and saw the earth nut with the brown wire from the light cluster was very loose and starting to rust a little.   I cleaned all this off and secured the earthing wire and nut.  Checked continuity from light cluster earth pin to body, and all ok.   I expected the fog light bulb to work at this point but no.  The voltage on the lignt cluster blue/white fog light line was 1.87V and only as bright as side lights.

 

I hooked up VCDS and started to investigate.   The output to the fog lamp shows as 12% for the rear right and 96% for the rear left.???   Surely this is the wrong was around.  The rear left fog light is the one that doesn't work.

 

I removed the rear left fog light bulb and the car reports a rear left fog light error in the maxidot display, and when I replace it the error is not shown.  I have swapped bulbs, interchanged the left and right light clusters and nothing makes the fog light bulb on the rear left light up.

 

I removed battery connection and unplugged the Voltage Control Module J519 BCM plugs.  I checked continuity between plug AA pin 6 and the Blue/White wire on rear left light cluster, and all is ok.   So I thought the BCM was faulty.    I bought a replacement secondhand BCM of the exact same type and model, and recoded it to the same BCM as the original unit using VCDS, which was accepted.   I even individually checked each byte of the coding and adaptation values to make sure it's all exactly the same.   Tested the fog light and it's the same problem, no left rear fog light lit, but rear right fog light working ok.  VCDS stating that Rear Right fog light is 12% and rear left fog light is 96%.   I think this is a software bug with VCDS 12.10.

 

Now I cannot believe that two BCMs have exactly the same fault on them.

 

I am completely at a loss of how to fix this "simple" problem, so please throw any ideas my way as I need some inspiration on what to do next.  I really do not want to buy another BCM from Skoda at £253 each.

 

Any ideas ?

 

Regards

Chris

 

J519 BCM info

------------------

               Address 09: Cent. Elect.
Control Module Part Number: 1K0 937 087
  Component and/or Version: BCM PQ35  H   020 0358
           Software Coding: 48180AB89041B1C04008008011000124010000AE424D81605C4440000000
            Work Shop Code: WSC 73430
                      VCID: EED8F9D23940936EED9

Advanced Identification
     Identification: HRE-HER
     Revision: 00020000
     Date: 22.11.08
     Manufacturer number: P401
     Test stand number: 1429
Flash Status
     Programming Attempts(application): 0
     Successful Attempts(application): 0
     Programming Status: 00000000
     Flash Date: ----.--.--
     Flash Tool Code: 00000 000 00000
Software
     BAP: 01.04.00
     Diag: 01.00.01
     CAN: 01.43.00
     TP 2.0: 03.04.00
     KWP2000: 03.00.00
     OSEK-OS: 04.02.00
     OSEK Net: 03.69.01
     LIN 2.0: 02.07.00
Misc.
     Hardware number: 1K0 937 087
     Workshop System Name: J519
VCDS Info:
       Labels: 1K0-937-08x-09.clb
 

[rwbaldwin]

By default, only the rear offside fog works in the UK. If you read the manual, it will state 'The rear fog light is located in the rear light array on the driver's side'.

[ChrisBarnes]

Is there any way to get the left rear fog light to work by modifying or reprogramming the j519 module.

I was convinced it worked when I first got hold of the car a year ago.

[Simon TDI Sport]

Yes it will need coding via vcds.

[ChrisBarnes]

Could you help me code it Simon.

I  have VCDS and have walked along the long coding bytes of module 09 (J519) looking for a bit to toggle or byte to set,  to switch it on, but cannot work out which one it is.  I am happy to experiment, but would like some insight if you have done this before.

Thanks for your help ....

 

One other question:

Why is the left fog light not enabled for use in the UK?

 

Regards

Chris

[Mike67]

My near side rear fog light is not working and there is a bulb in it, replaced it and still not working , can anyone help on this matter ,2016 hrs octavia

Edited 21 March, 2018 by Mike67

[Breezy_Pete]

See first reply by rwbaldwin.

On ‎10‎/‎01‎/‎2014 at 10:06, rwbaldwin said:

By default, only the rear offside fog works in the UK. If you read the manual, it will state 'The rear fog light is located in the rear light array on the driver's side'.