Alternator not charging solution - Polo 9n

Chat about your 9n Polo (inc GT and Fun)
Jollus
Bronze Member
Posts: 106
Joined: Sun Apr 06, 2008 2:07 am

Re: Alternator not charging solution - Polo 9n

Post by Jollus »

Cheers man I had a look and the battery light is there when I turn ignition on before starting car. Unusual why I've got that fault sitting on the ECU init. Ill print off the fault codes symptoms etc off Ross-tech wiki and leave it with my mate when he services the car and does timing belt for me next week. See if he can have a little stab around to find out why the faults there. I'll try and wipe the fault off and see if it comes back.
Bottlerocket
New
Posts: 3
Joined: Tue Jul 10, 2012 4:20 pm

Re: Alternator not charging solution - Polo 9n

Post by Bottlerocket »

This thread just saved me the cost of a new alternator! After 2 occasions of the ABS light coming on followed by the PAS light and losing power steering, the first time I turned it off and it wouldn't start again and the second time JUST started. Checked the charging and was 11.6v at idle so was ready to order an alternator but thought I'd check it on the diagnostic first and came up with the same P1503 fault code.

A quick search later turned up this thread, had a look underneath and sure enough both wired in the plug had snapped! Removed it and repaired it the same as the OP and now I have a working battery light (which also wasn't working) and charging at 14.3v on idle.

Big thanks for saving me a lot of time and money! :D
danwood76
New
Posts: 2
Joined: Fri Mar 15, 2013 10:14 am

Re: Alternator not charging solution - Polo 9n

Post by danwood76 »

I would just like to add that this also fixed the alternator charging issues on my 9n 1.4SE!

I had no fault codes in the ECU but I noticed that the alternator light never came on and occasionally my ABS light would come on (intermittent message failure or something). Took a look underneath and mine had broken in the exact same place.

A quick splice later and the alternator light now works as it should and it sits at 14V when idle!
I would also like to add that a few months ago I also had to repair the reversing light switch in the same way which is located around the same area so its obviously a bad spot for cable corrosion.

Thank you for the guide!
RUM4MO
Bling Bling Diamond Member
Posts: 5859
Joined: Sat Dec 30, 2006 9:12 pm
Drives: B8 S4 & 6R/6C1 1.2TSI 110
Location: Mid Lothian

Re: Alternator not charging solution - Polo 9n

Post by RUM4MO »

danwood76, your posting is a bit "annoying" in as much as I had thought the petrol engined cars were immune to this sort of failure - hum, I might need to check my wife's 10.5 years old Polo 1.4SE! Thanks for the heads up though.
marke
New
Posts: 1
Joined: Tue Jun 23, 2015 8:19 pm
Drives: 1.4 TDI 80PSI 2007

Re: Alternator not charging solution - Polo 9n

Post by marke »

Hi,

I'm getting all the low voltage errors listed previously along with no battery light. Taken the battery out but can't seem to find the sense wire or any broken wires.

Can anyone help me find this please?

One of the previous threads mentioned getting under the car?

Polo 1.4 TDI 80 2007

Thanks.
RUM4MO
Bling Bling Diamond Member
Posts: 5859
Joined: Sat Dec 30, 2006 9:12 pm
Drives: B8 S4 & 6R/6C1 1.2TSI 110
Location: Mid Lothian

Re: Alternator not charging solution - Polo 9n

Post by RUM4MO »

Marke, you have got to get under the front of the car to find the plug/socket, there are a couple I think mounted on a plate near the point where the engine and gearbox join, but maybe out towards the front a bit - it has been a long time since I looked there. The battery platform will probably stop you seeing this from above - along with other stuff!

Have another look at the pictures in the earlier posting for help in locating it, they will all have been taken from underneath the car.
slicker55
New
Posts: 17
Joined: Tue Jan 15, 2019 12:57 pm
Drives: 1.4TDI 2008
Location: West Mids, UK

Re: Alternator not charging solution - Polo 9n

Post by slicker55 »

Posts like this one are a real godsend, especially for the 'home mechanic' (like me)...

I only have one of those el-cheapo OBD readers off Amazon but it's showing 17911 and with the help of this post I'm quite optimistic of being able to fix it.

Thanks to everyone for contributing to date - really appreciated

I will let you all know how I get on :D
Peterjbdk
New
Posts: 1
Joined: Fri Jun 09, 2017 7:25 am
Drives: 9N Bluemotion
Location: Oxford

Re: Alternator not charging solution - Polo 9n

Post by Peterjbdk »

I just finished fixing mine on my Polo 9N Bluemotion. In case anyone has the same question, there is a release catch on the front side of the connector - facing towards the front of the car, which is hard to see when looking from the best position towards the rear of the unit. When released with a screwdriver, the connector slides off easily.I bought a cheap replacement connector from eBay - https://www.ebay.co.uk/itm/VW-AUDI-SKOD ... 2749.l2649. It did not fit and I had to reuse the old one by prising out the terminal block so I could solder some wire to the terminals; resealed with a glue gun and now everything works fine.
slicker55
New
Posts: 17
Joined: Tue Jan 15, 2019 12:57 pm
Drives: 1.4TDI 2008
Location: West Mids, UK

Re: Alternator not charging solution - Polo 9n

Post by slicker55 »

Polo 1.4 TDI (UK spec) 2008... same issues as outlined - not charging.

I am trying to locate the Alternator Sense Wire to check it's condition.

Standing at the front of the car and looking inside the engine bay, I have noticed two connectors slotted into a bracket just behind the oil filter housing.

Before I start scrambling under the car, is it possible VW changed the location of these connectors due to amount of issues outlined?

I have taken a few pics but, when I try to upload, encountering "Sorry, the board attachment quota has been reached".
CarbonChaos
Silver Member
Posts: 405
Joined: Mon Sep 03, 2018 9:43 pm
Drives: 2015 6C GTI DSG Oryx white 3 door.
Location: South west uk

Re: Alternator not charging solution - Polo 9n

Post by CarbonChaos »

These connections are located in front of the gearbox on the left hand side of the car,best viewed from underneath the car once the under tray has been removed (6 screws) there are usually 2 connectors slotted into a metal bracket bolted to the gearbox housing.

I too have had to repair the reverse lamp switch wiring recently,to save all the faff of pin removal etc I just bought the correct pre wired plug from eBay and joined the new plug onto the loom once I had cut the old plug off.
slicker55
New
Posts: 17
Joined: Tue Jan 15, 2019 12:57 pm
Drives: 1.4TDI 2008
Location: West Mids, UK

Re: Alternator not charging solution - Polo 9n

Post by slicker55 »

Thanks for replying... any further assistance will be greatly appreciated

I removed the under tray and had a really good look around, paying particular attention to the area you describe.

Just to clarify, I believe I am looking for a 'yellow wire'... this isn't the first time I've tried to find this wire (without success).... once again, absolutely no sign of a yellow wire. However, I did find a clump of wires wrapped in electrical tape adjacent to an empty bracket and two translucent pink splice connectors?

Does this sound like I'm looking in the right place?

My initial thought was that someone has previously repaired the original connector but I have owned the car from new and cannot recall any work having been done. I also have a feeling I may have seen the same two connectors in a picture somewhere on the web so maybe these are original fitments. In any case neither of these wires are yellow!

So, just a bit of a recap... ignition on, (without engine running) no battery light ... start engine, no battery light... rev engine, battery light comes on... release the accelerator, battery light off, so, battery light only comes on at the peak of rev ... about 2000rpm

I've tested the alternator and suspect it needs replacing... so, I'm wondering if there's any point in spending any more time trying to find this elusive wire given the battery light does come on if I rev the engine?
CarbonChaos
Silver Member
Posts: 405
Joined: Mon Sep 03, 2018 9:43 pm
Drives: 2015 6C GTI DSG Oryx white 3 door.
Location: South west uk

Re: Alternator not charging solution - Polo 9n

Post by CarbonChaos »

The red battery light should illuminate when you key on engine off , this shows a good circuit between the alt and instrument cluster if this is not happening there is a fault
This could be internal to the alt equally a broken wire
slicker55
New
Posts: 17
Joined: Tue Jan 15, 2019 12:57 pm
Drives: 1.4TDI 2008
Location: West Mids, UK

Re: Alternator not charging solution - Polo 9n

Post by slicker55 »

@CarbonChaos

Thank you for your advice and words of encouragement - a really good poke around this afternoon and still nothing resembling the elusive 'yellow wire' - starting to wonder if VW has repositioned this out of harms way...

I am hoping a pic I am trying to upload will be successful this time...

I am hoping someone with a VW Polo 1.4 TDI (2008) will confirm if they have the 'yellow wire' underneath the engine AND the two connectors fixed to a bracket directly behind the oil filter housing

edit: er... just tried to upload a pic and that will be a no then :(
slicker55
New
Posts: 17
Joined: Tue Jan 15, 2019 12:57 pm
Drives: 1.4TDI 2008
Location: West Mids, UK

Re: Alternator not charging solution - Polo 9n

Post by slicker55 »

CarbonChaos wrote: Mon Jun 07, 2021 1:22 pm The red battery light should illuminate when you key on engine off , this shows a good circuit between the alt and instrument cluster if this is not happening there is a fault
This could be internal to the alt equally a broken wire
Thanks, your moral support is invaluable...

I have moved on quite a bit since my previous post and done some extensive testing mainly to check for continuity in the wiring.

Some posts advise that earthing one of the wires going into the alternator will cause the battery light in the instrument cluster to illuminate when the ignition is turned ON

On my car the Blue Wire is connected to the pin on the rounded side of the plug (which I believe is L) and the Brown Wire is connected to the other pin (which I believe is DFM)

Would you be kind enough to confirm which one of the two wires going into the alternator should be used to conduct this test?
CarbonChaos
Silver Member
Posts: 405
Joined: Mon Sep 03, 2018 9:43 pm
Drives: 2015 6C GTI DSG Oryx white 3 door.
Location: South west uk

Re: Alternator not charging solution - Polo 9n

Post by CarbonChaos »

By earthing a wire you are testing the circuit, as in your previous post your battery light does illuminate under certain conditions this seems pointless .

I’d be fitting an alternator
Post Reply