Alternator Workshop

[mexico5lro]

Hi folks, I have a 03 plate 130 tdi and have just had the 'Alternator Workshop' warning light come on and also the battery light. This is totally intermittent and car runs fine, all lights on etc.

I checked the terminal voltage and got 14.4v at idle, I would assume that the alternator is working fine from this reading.

Battery is 7 months old and belt was changed 12k ago when timing belt service was done at 60k.

Any ideas, I know Volkswagens warning systems can be tempremental at times, just wonder if this is another example and dont want to change the alternator if not required.

Any ideas???

Chris:aargh4:

[kenney]

Can you remove the voltage regulator and check the brushes

[mexico5lro]

Yes I was going to do that for a check, my only doubts are that I cant see anything wrong with the alternator output as far as battery terminal voltage is concerned. I have a CV boot to do on the misses car in the morning so whilst I am grubbed up I will have a check. Chris

[martin1810]

Check all your bulbs, especially brake lights. Remove and clean connections on alternator. Check you have 14.4v at battery terminals with engine running.

[PassSPORT]

Check all your bulbs, especially brake lights. Remove and clean connections on alternator. Check you have 14.4v at battery terminals with engine running.

I too have this message. What do u mean about checking brake light bulbs? and now you mention it, a work mate told me he saw the other day that one of my brake lights was out, but I checked them today and they are fine. Is there any connection?
Also I have a multi-meter, but I don't know how to use it, any clues?

[martin1810]

Passats seem to get upset if the brake light bulbs are corroded, loose or have different wattage. It's always worth checking and cleaning connections and bulb holders. It is also worth cleaning battery connections and wires on the alternator. As to the multimeter. Never use the amp settings on cars unless you are certain of what you are doing. Never use the resistance (ohms) setting with the battery connected. To test your alternator output, set the multimeter to DC volts, 20V setting or similar. Place one contact on each battery terminal. You should get 14.4v with the engine running. If you have the multimeter leads the wrong way round on the battery, it will read -14.4v. Just swap them round. Good luck.

[PassSPORT]

Passats seem to get upset if the brake light bulbs are corroded, loose or have different wattage. It's always worth checking and cleaning connections and bulb holders. It is also worth cleaning battery connections and wires on the alternator. As to the multimeter. Never use the amp settings on cars unless you are certain of what you are doing. Never use the resistance (ohms) setting with the battery connected. To test your alternator output, set the multimeter to DC volts, 20V setting or similar. Place one contact on each battery terminal. You should get 14.4v with the engine running. If you have the multimeter leads the wrong way round on the battery, it will read -14.4v. Just swap them round. Good luck.

Is that with all electrics on or off, and is there any leeway under or over the 14.4v.
Thanks

[martin1810]

With all electrics off you should get 14.4v and when you switch electrics on the alternator should regulate and stick to 14.4v. As long as you get between 13.5v and 14.5v you are fine. You don't want it too low or too high.

[PassSPORT]

I checked the voltage at the battery and alternator today and it's spot on. Last night I went for a quick spin, about 6 miles in total and it only showed the message the once for a couple of seconds. Earlier that day when it first done it, it wouldn't shut up.
I did notice that it seems to do it when u are going over say 20mph.
Im puzzled what to do now, could it be the 2 wire alt connection getting a bad connection ( which I can't for the life of me get off).
The belt deffinetly seems to be tight enough.

[sherlockuk]

Did you sort this out???

Mine has the same, but now the battery has gone flat!! I have booked it into the garage and it could be the brushes? Have not got time to check so may just ask them and hope that they are honest if it is just the brushes!

Cheers

[grhdylan]

I got this message once just after going through a ford, must have got the belt wet & it started slipping........lasted about 10 seconds........... just a thorght, have you checked the belt , see if its tight ?

[PassSPORT]

Same thing happened to me a while ago. I cleaned the connections to the alternator ,and replaced a rear bulb a while after that, which was working intermittently. Haven't had a problem since. :D