Ok, thanks for help re 'how to take the tension off the drive belt for the Alternator on my Polo 1.4TDi, 2003 3 Cyl model.

New Alternator fitted, but still no voltage input to battery. Why ??

So, battery charged over night on mains charger. Diesel engine starts straight away on coldest morning so far. Therfore, battery seems OK at 12.7volts. Put volt meter across battery, 11.7 and gradually going down as 'system' draws current, so, clearly, Alternator not charging and exactly the same as with Old Alternator.

What else can I change or check please ?? ( one suggestion from a neighbour was bad earthing, but surely, the starter would not turn on a morning like this one, if the earthing was suspect, would it ?? )

One point I MUST mention is, at initial ignition switch turn on, the battery symbol does not appear on the instrument panel, amongst all the others. Yes, it could simply be the bulb, but could it be more sinister.

Any clues please ladies and gentlemen will be very much appreciated.

Thanks, Richard

( PS. I am 66 yrs of age and have 'messed' with cars all my life. In the past, a volt meter reading across the battery has always revealed a failing alternator, which is why I went out and bought a new one !! I am baffled now, but there MUST be an answer out there somewhere eh !?? )

Hi Richard,

Unfortunately the alternator control is linked into the engine ecu and the body computer, so you will need to get it connected to vagcom/vcds diagnostics

Checking alternator -C-

– Connect the vehicle diagnosis, testing and information system -VAS 5051A- → Chapter.

– On the vehicle diagnosis, testing and information system -VAS 5051A- select “Guided fault finding” mode.

– Using “GoTo” button, select “Functions/component” and the following menu options in succession:

- Body

- Electrical system

- 27 - Starter, current supply

- Electrical components

- C - Alternator

Hi Richard,

Unfortunately the alternator control is linked into the engine ecu and the body computer, so you will need to get it connected to vagcom/vcds diagnostics

Checking alternator -C-

– Connect the vehicle diagnosis, testing and information system -VAS 5051A- → Chapter.

– On the vehicle diagnosis, testing and information system -VAS 5051A- select “Guided fault finding” mode.

– Using “GoTo” button, select “Functions/component” and the following menu options in succession:

- Body

- Electrical system

- 27 - Starter, current supply

- Electrical components

- C - Alternator

Hi Nige

You are astar with your help - thanks mate. But what does 'vagcom/vcds diagnostics' mean - is it off to the VW Garage and get connected to their diagnostics or is it something that I can download and check through systematically. Forgive me for being a bit dumb, but I was weaned on 'points' n 'dynamos' etc etc !!!

Cheers, Richard

Hi Richard,

Unfortunately the alternator control is linked into the engine ecu and the body computer, so you will need to get it connected to vagcom/vcds diagnostics

Checking alternator -C-

– Connect the vehicle diagnosis, testing and information system -VAS 5051A- → Chapter.

– On the vehicle diagnosis, testing and information system -VAS 5051A- select “Guided fault finding” mode.

– Using “GoTo” button, select “Functions/component” and the following menu options in succession:

- Body

- Electrical system

- 27 - Starter, current supply

- Electrical components

- C - Alternator

Hi Nige

You are astar with your help - thanks mate. But what does 'vagcom/vcds diagnostics' mean - is it off to the VW Garage and get connected to their diagnostics or is it something that I can download and check through systematically. Forgive me for being a bit dumb, but I was weaned on 'points' n 'dynamos' etc etc !!!

Cheers, Richard

Hi Richard,

Vagcom/vcds is a software program that you can run on a laptop to read the diagnostic fault codes and if you have the full licenced version, you can do resetting and testing of the various computers, valves, sensors etc, like the dealer can do. The basic program can be downloaded for free from www.ross-tech.com they are also who you buy the licence from for $ 99 Then you will need the USB lead from the laptop to the 16 pin obd connector on the car, ebay is the cheapest source for the cable, search for vagcom cable.

As your car is an oil burner, it does'nt have to comply with the eobd 2 standard, so most of the generic fault code readers that the likes of Halfords sell, will not connect to your car, as it uses VW's own 4 or 5 number codes instead of the eobd "P" codes

Like you I also cut my teeth on the "simple" cars, so I'm still learning to adapt to these computer controlled money pits!!

Nigel

Have you checked for a voltage out of the alternator feed? is the alternator a recon?, at the garage i worked out we had the odd faulty recon sent out to us, so it sometimes does happen. Tommy.

Does it generate any voltage if you hold it at say 2000rpm?

Have you checked for a voltage out of the alternator feed? is the alternator a recon?, at the garage i worked out we had the odd faulty recon sent out to us, so it sometimes does happen. Tommy.

Hi Tommy

It was the Alternator afterall !! Fitted an RTX replacement - nothing. Spent hours 'effing' about with meters, forums, YouTube etc etc. Went to a different Parts supplier and bought a Bosch. Guess what, it all works....................Moral of the story...............

Thanks for your help and suggestions.

Richard

Does it generate any voltage if you hold it at say 2000rpm?

Hi harris.racing

It was the Alternator afterall !! Fitted an RTX replacement - nothing. Spent hours 'effing' about with meters, forums, YouTube etc etc. Went to a different Parts supplier and bought a Bosch. Guess what, it all works....................Moral of the story...............

Thanks for your help and suggestions.

Richard

Glad you're sorted then buddy!

Glad you got it sorted mate, just shows that by fitting a new faulty part can mislead people into false diagnosis.

Tommy.