Left dipped headlight issue

[prospero]

Hello, my first post as this is about my wife's 2016 reg 1.2 TSI

I replaced a bulb in this today but it didn't fix the issue - in fact both bulbs tested OK. So my next thought was fuses (no voltage at the bulb holder) but a general Google search brought up much confusing information, the most misleading of that may be that there are separate fuses for left and right dipped headlights but it sounded great so I jumped in and looked at a few fuses before realising the fuse box layout didn't exactly match. So I found one that did but no appropriate fuses for the lights are listed.

I then found that the car wouldn't start and shows EPC and the engine block symbol. So I now have two problems. Could I have put a fuse back in the wrong slot? Is there a fuse for the EPC? Did my attempt to fix the light cause this directly or perhaps indirectly. And how do I fix the light? In case it helps the battery was showing 12.5V.

I've charged the battery and also disconnected it from the car for 10 minutes.

As you may imagine my wife wishes I'd not touched the car so help will be much appreciated (although she did ask me to)

Thanks for listening

David

[ciclo]

Welcome.

For the POLO '6C' (2014-2018), the headlights are managed by the BCM, there is no fuse.
It's likely that once the bulb has been replaced, the fault memory must be cleared with a diagnostic tool for the affected light to work again.

Use the memory to recall the time when you touched the fuse box to restore everything to its original state...
...or take a picture of the fuse box, so hopefully some sharp-eyed user can tell you what's wrong with it.

[prospero]

Thanks.

There was only really one fuse that I wasn't sure where it came from as I thought I had taken out a different one. Sounds mad I know but I am getting on a bit.

I did a lot of 'Googling' yesterday and that is the first time I've seen mention of the BCM - I wish that had appeared earlier then I would never have touched a fuse.

I did eventually take a photo yesterday to compare with the multiplicity of diagrams on the internet so I've attached that

fuses.jpg (3.86 MiB) Viewed 3058 times

.

[prospero]

I've been through the list of fuses on this site and compared to ours. The only that looks to me somewhat odd is 30A in position 8 which is for a dual clutch gearbox. The rating is right so maybe that's a red herring.

I've borrowed an OBD and it gets a code P025C related to the fuel pump module controle circuit low. According to the list Fuse 49 is used for this but that is present and correct.

[ciclo]

I was going to post and read your new post.

However...



Check that the SC8 fuse slot is empty, then replace the 30A fuse to the SC13 fuse slot.
The SC13 fuse is for the +15 power supply of various systems.

[RUM4MO]

Ah, so at least you know that the fuse boxes on RHD cars is a rotated version of what LHD cars have - thanks VW!

I tend to take a picture of the fuse boxes when the car is new, can help later on in the car's life.

I'm sure that I've read that you need to clear logged faults to restore power to the lights, maybe even just disconnect your battery for 10 minutes and then short the +ve lead to the -ve lead for "good measure", before reconnecting the leads to the battery.

Some functions will complain, like maybe you will need to drive a short distance and turn the steering wheel from lock to lock before any warning lights go out and sort out the electric windows, though it will be curtains for your fuel computer saved data I'm afraid - if that bothers you (I've been logging fuel figures for too many years, so losing stored data would annoy me for a minute or so!).

Edited to change "so functions" to "some functions"

[RUM4MO]

Picture of my wife's 2015 VW Polo 1.2TSI 110PS 6MT 5Door SEL with winter pack

Second Polo 12TSI SEL fuse box 111016.JPG (750.25 KiB) Viewed 3035 times

[prospero]

Thanks for the information on those fuses - will try that now.

[prospero]

Thanks, that was it and that was the first fuse I removed to check but it wasn't the one I intended to check - never mind, too long a story. Thanks so much though.

Now to sort out the light though it looks as if a BCM issue is not for the likes of me to fix.

[ciclo]

I've been through the list of fuses on this site and compared to ours. The only that looks to me somewhat odd is 30A in position 8 which is for a dual clutch gearbox. The rating is right so maybe that's a red herring.

I've borrowed an OBD and it gets a code P025C related to the fuel pump module controle circuit low. According to the list Fuse 49 is used for this but that is present and correct.

Some fuses feed other fuses through relays (depending on conditions)...

[prospero]

I did try the 10 minutes battery disconnect but not the shorting. Losing fuel consumption data would certainly not be concern to my wife so I may try that.

The other odd thing is that I can't get rid of a tyre pressure warning. I think one tyre must have a slightly dodgy valve as we get these warnings infrequently and after pumping that tyre and resetting as prompted the alert disappears ... but not this time.

I see SC33 mentions 'Control unit for structure-borne sound'. What on earth?

[RUM4MO]

Structure borne sound - unfortunately that is just fitted to GTI level models, it seems like the exhausts and sound proofing are so good that there needs to be a "better" way to add excitement in the driving experience, that is where that system comes into use! And no, I'm not joking!

Edit:- there has been, across the VW Group marques, a few owners finding that the TPMS can "play up", I've not had any issues so far. One issue can be an "odd" make and/or rating or size of tyre being fitted to a car, another can be a partially seized brake - that will cause that hub and so wheel and tyre to increase in temperature and so in pressure.

In case you don't know, it is just the ABS wheel sensors output that gets monitored, so if a tyre drops in pressure, the frequency of the signal impulses from that tyre will reduce, conversely, if that tyre increases in pressure, the ABS signal impulses from that wheel will increase, both increasing and decreasing can end up forcing a TPMS warning. Even a faulty ABS wheel sensor can cause a problem, and even a failing wheel bearing, typically, with these cars, it is a front wheel bearing that fails first, I've replaced he front wheel bearings on my wife's 2015 Polo a couple of year a ago, mileage was only roughly 40,000 miles, which was a bit early!

The shorting of the leads, as you probably know already, is to just dump any stored charge that might stop the controllers from losing their stored faults.

[prospero]

Thanks again.

In fact shorting the leads has got rid of the tyre warning - just didn't take the dipped headlamp fault with it.

I have a BMW with run-flat tyres and TPMS has been a bit of a pain. At my last service the garage wanted to replace both rear TPMS units at a silly cost simply because they couldn't inflate the tyres. I couldn'r either if I went to filling station but a cheap battery powered device worked perfectly as did the TPMS units. Just replaced those tyres and changed the valves stems for £12 each so all good now.

Many thanks for giving up your time to help.

[prospero]

So does anyone know how we can fix the original dippred headlight fault? The (old) ODB does not show any error codes but the damn tyre warning is back.

If it has to be a professional fix then so be it but I'd like to make sure I've exhausted any cheaper solutions. I've read enough about the BCM to convince me I shouldn't go near it.

[ciclo]

Clearing the DTCs doesn't imply any type of problem for the vehicle, so you shouldn't have any fear when performing this operation with any diagnostic tool on any control module/unit of the vehicle (including the BCM).

It's strange that even if the OBD diagnostic tool you're using is older, it doesn't tell you that a fault was stored in the BCM.

Which side did the bulb burn out on? On the battery side (left) or the other?
Try double-checking that the connector that fits over the bulb pins isn't sulfated, oxidized, corroded, or dirty. A zero-residue contact cleaner will help remove any dirt.
If it's the battery side, it's best to remove the battery for checks, inspections, or cleaning, but you'll need a diagnostic tool to clear all DTCs due to the battery disconnection.