Battery/generator fault message - Cluster?

[mat59]

Hi all,

So, I have a new fault with my 2001 TT. Was driving into work the other day and I randomly get the battery/generator red fault message on the LCD screen. I also got a smell of burning. It was early morning and very misty so suspected the very misty conditions outside May have caused a short or something. Later that day when it was much warmer I went to check the car and fault message on the display was still there. The voltmeter was reading straight between 12 and 14 (13)with engine running and all consumers off.

I took it to my Indy specialist who did some tests with a multimeter and said the alternator was weak. Makes sense as the car is at approx 80k miles. He has since replaced the alternator with a Porsche refurb part. Collected the car today and he told me the warning is still on the cluster display. With all consumers off it is now reading two thirds of the way between 12 and 14, so about 13.5ish. He says he has checked all wiring and cannot see any fault. He suspects the cluster to be at fault. He knows I have had issues with the cluster before.

Background to all of this (couple of threads started and followed up on here) is that my oil level readout functionality stopped working on my cluster. After changing oil level sensors and two checks at separate Indy specialists it was traced to a faulty cluster. I sent it off to a guy on here who has fixed the fault very economically compared to the huge cost of a replacement cluster. Doubt this issue is related to the oil level fix. No issues with the car since.

The battery is only six months old but is a 74 Ah not 80 Ah.

Any ideas on where my faults lies?

Thanks,

Matt

[JFP in PA]

Hi all,

So, I have a new fault with my 2001 TT. Was driving into work the other day and I randomly get the battery/generator red fault message on the LCD screen. I also got a smell of burning. It was early morning and very misty so suspected the very misty conditions outside May have caused a short or something. Later that day when it was much warmer I went to check the car and fault message on the display was still there. The voltmeter was reading straight between 12 and 14 (13)with engine running and all consumers off.

I took it to my Indy specialist who did some tests with a multimeter and said the alternator was weak. Makes sense as the car is at approx 80k miles. He has since replaced the alternator with a Porsche refurb part. Collected the car today and he told me the warning is still on the cluster display. With all consumers off it is now reading two thirds of the way between 12 and 14, so about 13.5ish. He says he has checked all wiring and cannot see any fault. He suspects the cluster to be at fault. He knows I have had issues with the cluster before.

Background to all of this (couple of threads started and followed up on here) is that my oil level readout functionality stopped working on my cluster. After changing oil level sensors and two checks at separate Indy specialists it was traced to a faulty cluster. I sent it off to a guy on here who has fixed the fault very economically compared to the huge cost of a replacement cluster. Doubt this issue is related to the oil level fix. No issues with the car since.

The battery is only six months old but is a 74 Ah not 80 Ah.

Any ideas on where my faults lies?

Thanks,

Matt

 

Yes, check the voltage drop across the large primary cables running from the battery to a junction and then down to the starter.  These cables are well known for developing internal corrosion, so there is nothing to see, but the resistance goes way up, leading to a large drop in voltage and cable overheating.  If you see more than 0.5V drop, the cables need to be replaced.

[mat59]

Just checked with a multimeter. Seeing 12.38 with engine off having been sat for two hours. With engine idling and all consumers off I'm seeing 13.7.

Is this OK?

[Ahsai]

When the warning pop up, did you notice what's the voltage reading? Since you said the warning is intermittent, it will help a lot if you get this tester and try to catch it when it's in action http://www.amazon.com/INNOVA-3721-Battery-Charging-Monitor/dp/B000EVWDU0/ref=sr_1_5?ie=UTF8&qid=1443898650&sr=8-5&keywords=Innova+tester

In general, the voltage needs to be 13.5v or higher even with some load. What's the voltage at idle when you turn on the a/c and low beam? It should still be 13.5v or higher.

[mat59]

When the warning pop up, did you notice what's the voltage reading? Since you said the warning is intermittent, it will help a lot if you get this tester and try to catch it when it's in action http://www.amazon.com/INNOVA-3721-Battery-Charging-Monitor/dp/B000EVWDU0/ref=sr_1_5?ie=UTF8&qid=1443898650&sr=8-5&keywords=Innova+tester

In general, the voltage needs to be 13.5v or higher even with some load. What's the voltage at idle when you turn on the a/c and low beam? It should still be 13.5v or higher.

Hi,

 

Didn't notice the voltage reading when the message appeared. However, later that day when I checked again whilst the car was idling and driving to my mechanic with AC, lights, radio etc off it was reading just above 13 volts. The fault isn't intermittent.

 

Since having the alt replaced it is now reading 13.7 at idle with no load.

 

I will check later what voltage I am getting with lights, radio and AC on.

Edited October 4, 2015 by mat59

[mat59]

Right, I just checked the car and it's charging at 13.42-13.5 at idle with the engine running and under load (lights, radio, AC on). I haven't driven the car in 24hrs before I started it. The battery was reading 12.08 before I started the engine.

Do both seem low?

[JFP in PA]

Right, I just checked the car and it's charging at 13.42-13.5 at idle with the engine running and under load (lights, radio, AC on). I haven't driven the car in 24hrs before I started it. The battery was reading 12.08 before I started the engine.

Do both seem low?

 

That is right at the very bottom of the acceptable range, so yes, it is low.

 

And I would still suggest doing a voltage drop test across the primary battery cables for the reasons stated above.

[mat59]

Right, I just checked the car and it's charging at 13.42-13.5 at idle with the engine running and under load (lights, radio, AC on). I haven't driven the car in 24hrs before I started it. The battery was reading 12.08 before I started the engine.

Do both seem low?

 

That is right at the very bottom of the acceptable range, so yes, it is low.

 

And I would still suggest doing a voltage drop test across the primary battery cables for the reasons stated above.

Thanks, JFP.

Where are these primary battery cables and how would you test them. When the warning message came on it was during very heavy fog so there was lots of moisture in the air. I got a burning smell in the cabin, so I get the idea something shorted or burnt out!?

[JFP in PA]

 

 

Right, I just checked the car and it's charging at 13.42-13.5 at idle with the engine running and under load (lights, radio, AC on). I haven't driven the car in 24hrs before I started it. The battery was reading 12.08 before I started the engine.

Do both seem low?

 

That is right at the very bottom of the acceptable range, so yes, it is low.

 

And I would still suggest doing a voltage drop test across the primary battery cables for the reasons stated above.

Thanks, JFP.

Where are these primary battery cables and how would you test them. When the warning message came on it was during very heavy fog so there was lots of moisture in the air. I got a burning smell in the cabin, so I get the idea something shorted or burnt out!?

 

 

I am referring to the heavy cables that run from the battery to a terminal junction and then down to the starter.

[Ahsai]

12.08v for a battery is really low. There are a few possibilities.

- marginal battery

- battery is not charged sufficiently

- parasitic drain when car is parked

13.5v with load should still be able to charge the battery. Do you do very short drives so not enough time to recharge the battery? I know you said the battery is only 6 months old, it's still a suspect as it can fail prematurely. Same goes for a new or rebuild alternator. They could also fail out of the box.

I suggest checking the battery and parasitic current drain when the car is parked.

[mat59]

12.08v for a battery is really low. There are a few possibilities.

- marginal battery

- battery is not charged sufficiently

- parasitic drain when car is parked

13.5v with load should still be able to charge the battery. Do you do very short drives so not enough time to recharge the battery? I know you said the battery is only 6 months old, it's still a suspect as it can fail prematurely. Same goes for a new or rebuild alternator. They could also fail out of the box.

I suggest checking the battery and parasitic current drain when the car is parked.

Thanks for that.

 

I don't do short drives but only use the car a few days per week. I'm probably going to take it up to another specialist in the next few days. I am wondering if the battery is on its way out and causing the voltage to be so low when it is charging off the alternator. Still doesn't explain the strong burning smell I had when the batt/generator warning light came on. I'll report back when i get it sorted! Needs a service anyway so I'll have the specialist look at it.

[Highlander]

 

12.08v for a battery is really low. There are a few possibilities.

- marginal battery

- battery is not charged sufficiently

- parasitic drain when car is parked

13.5v with load should still be able to charge the battery. Do you do very short drives so not enough time to recharge the battery? I know you said the battery is only 6 months old, it's still a suspect as it can fail prematurely. Same goes for a new or rebuild alternator. They could also fail out of the box.

I suggest checking the battery and parasitic current drain when the car is parked.

Thanks for that.

 

I don't do short drives but only use the car a few days per week. I'm probably going to take it up to another specialist in the next few days. I am wondering if the battery is on its way out and causing the voltage to be so low when it is charging off the alternator. Still doesn't explain the strong burning smell I had when the batt/generator warning light came on. I'll report back when i get it sorted! Needs a service anyway so I'll have the specialist look at it.

 

 

Please report back what your specialist finds.  

 

Good Luck!

[vglnte1]

I had this issue.  10$ says its the voltage regulator in the alternator.  maybe the refurb unit was bad  is the car going into a limp mode?

[Billy Bob]

It's likely the voltage regulator as noted earlier. I had a similar issue on my daily driver. I installed a refurbished alternator and that was money down the drain. You are better off buying a new voltage regulator.

If you absolutely want to be sure. Measure the voltage of the battery while the car is running with a multimeter. The voltage reading should be steady. A bad voltage regulator will show a low or fluctuating rate which causes the battery not to charge properly.

[mat59]

Forgot to report back in this!

My specialists both think the cluster is at fault and recommended a new one. I don't intend to do this because of the cost involved. Instead I will send it off to Steve Eiche who fixed it last time I have an issue with the oil level indicator. Will report back if this works but won't be for a while as I'm too busy driving the car!