2002 Polo 1.4 TDi alternator charging fault
Hi,
I have got a problem with my girlfriends 2002 1.4TDi Polo. On Sunday I went to start the car, the engine turned over slowly, stopped and then sprung in to life albeit sounding as though the battery was going flat. We set off home and a couple of miles in to the journey the radio started blinking on and off, then the power steering, rear seat lock and brake lights on the instrument cluster lit up shortly before the power steering died. Thee were only less than a mile from home so I wrestled the steering and got back. Once turned off the engine wouldn't start and certain things such as electric windows and the radio wouldn't work. I checked the battery voltage and it was 2.5V.
Yesterday I jump started the car and checked the voltage and still it sat at 2.5V even when revving to over 3k rpm. Now the car will start and run without any spurious warning lights even though it only has 2.5V showing at the battery! We haven't driven it again just in case.
I found this thread - https://www.vwaudiforum.co.uk/forum/s...ailure-!/page2 - and have taken the instrument cluster out and checked the continuity on the blue wire to the alternator. On our Polo it is pin 15 of the plug behind the cluster. The continuity is fine but I am not convinced that the alternator is at fault as according to the other thread it is energised by the cluster? I have checked and the battery light is not coming on at any point when the ignition is turned on or the engine is started. Does this sound like a cluster problem and is there anyway to tell for sure?
As an aside for a few weeks the oil low level light has been on even though the oil is fine (we have checked many times both before and after using the car). I'm not sure if this is related or whether the oil level sensor is also faulty.
Any help wouldbe very gratefully received!
Thanks,
Mark.
Re: 2002 Polo 1.4 TDi alternator charging fault
It's still not receiving a charge from the alternator though, there is something more wrong than just the battery being a bit flat.
Re: 2002 Polo 1.4 TDi alternator charging fault
You need a multimeter to check properly as a start. Measure across the battery(+) to give you a starting voltage - then change the MM negative lead to another good earth but after the earth lead from the battery. This helps to see if the earth strap/cable is at fault.
Then you need to measure the output from the back of the alternator(+) using a good earth but not the battery (-). The fact that you had 2.5V may suggest dead cells in the battery also - only when you charge and recheck will you know for sure.
Re: 2002 Polo 1.4 TDi alternator charging fault
Across the battery terminals with a good multimeter was 2.5V. I also tried from a good earth near the back of the bay and got identical readings. Interestingly if I hold it on the terminals whilst the engine is running I can see the voltage dropping slowly by hundredths. Once the engine is stopped it creeps back up slowly.
I will check the output from the back of the alternator as you suggest and see what this brings back, thanks.
Re: 2002 Polo 1.4 TDi alternator charging fault
If the warning light on the dash is not working when you switch on the ignition, this normally indicates the alternator is faulty. The warning light usually earths through the brushes & if they are worn out, the light does not come on. I think your alternator needs rebuilding, or exchanging.
Re: 2002 Polo 1.4 TDi alternator charging fault
I've now replaced the alternator with a new unit and the fault remains. There is no charge at the alternator output so it's not a fault in the wiring to the battery.
Can anybody offer any more help? I've just spent £160 I could well have done without spending and still can't drive the car. :(
Re: 2002 Polo 1.4 TDi alternator charging fault
Quote:
Originally Posted by
i-macca
I've now replaced the alternator with a new unit and the fault remains. There is no charge at the alternator output so it's not a fault in the wiring to the battery.
Can anybody offer any more help? I've just spent £160 I could well have done without spending and still can't drive the car. :(
Does the battery light on the dash come on now? And, have you got battery voltage at the main terminal on the alternator? And, is the battery fully charged?
Re: 2002 Polo 1.4 TDi alternator charging fault
No, still no dash light when the ignition is turned on or once it's running. I've got battery voltage at the main terminal on the alternator. I've also checked all of the fusable links in the battery lid and they all have no resistance (same as between there and the alternator terminal). The battery is not fully charged but has enough grunt to start the car. I've never known a system that requires the battery to be fully charged to charge it though?
Re: 2002 Polo 1.4 TDi alternator charging fault
Quote:
Originally Posted by
i-macca
No, still no dash light when the ignition is turned on or once it's running. I've got battery voltage at the main terminal on the alternator. I've also checked all of the fusable links in the battery lid and they all have no resistance (same as between there and the alternator terminal). The battery is not fully charged but has enough grunt to start the car. I've never known a system that requires the battery to be fully charged to charge it though?
With the ignition switched on, is there any power to the small wire to the alternator? If not, you may have a problem with the dash connections or the bulb.