Hello all,

I was driving my 05 C2S 51,000 miles to work this am and the Battery/generator warning light came on three different times in a 45 minute drive. The light only came on for a brief second then went away each time. The ! never came on. The car drove fine. The weather was 28 degrees and I was in slow moving traffic the entire trip. I’ve been driving this car the past week as I am having trouble w/ my 1series. No issues any this week w/ my 911 except for this message. Within the past three years I have replaced the battery, alternator and that battery strap thing.

I do do have a V1 that I believe is hard wired straight to the fuse box and a DSC w/ accelerometer. I did not have my cell phone charger plugged in. I only had the headlights on, ac set at 72 degrees and radio/Navi on.

Do you see any concerns or it was just a fluke?

No such thing as a fluke. Early earning of an issue but could be be battery, alternator, voltage regulator, who knows?

I’d stop at my Indy or P dealer or Auto Zone and see if they can plug in and find a fault code.

Also your Valentine may have a VDC display option so you could monitor the bus voltage static and charging. My Escort has this feature I leave it on as the default in the 993 and 997. Static should be about 12.5 vdc and charging 13.75 to 14.25 vdc.

The car is trying to tell you something.

I just ran to Firestone that is close to my work. They hooked up and checked my battery and alternator w/ their computer. They felt like it was fine. The mechanic just took a wild guess that it could possibly be a lose belt from the tensioner. Would this cause my light to come on & back off?

Gotcha yes I do have a duremetric enthusiast and a Foxwell NT520 Pro. Will either of these work.

The tapes look good for voltages. I suppose the belt could cause an intermittent issue more like instantaneous. Has the belt service been done? Was it wet when the lights came on? Thinking maybe a slipping belt like the old days when you drove through a puddle. Seems odd w a grooved serpentine belt though.

Pretty sure when the alternator was replaced about 3 yrs ago.

I would lean more on the side of a battery as it was cold. Two things kill batteries, hot and cold. You need to do a load test on the battery and not just a voltage test to see if it is good. Any car parts place will do that for free. I bet that is your issue.

I believe the test tape shows battery voltage drop while cranking - hence this is the load test of the battery. I’m not sure what the test parameters are but I think the tape is saying that the battery voltage didn’t collapse under cranking load. Hence a battery in good shape.

So crazy my car has driven just fine the past two days too & from work. About a 45 minute drive each time. I have romped on it and driven normal. I can’t believe that I’m having 1series trouble at the same time. I hooked up my Foxwell NT520 & cleared any codes Incase the car started acting weird so I could look it up. After I cleared the codes I realized that I should of looked at what I erased. Rookie move for sure.

Mechanic though it was a battery issue so he replaced it. Car drove fine for two days then the warning flashed again. Mechanic replaced the voltage regulator and I have made it two days trouble free. Hopefully this has satisfied the warning light situation. Here is a pic of the voltage regulator removed. The mechanic said that the two black tips should be the same size. One is just a little higher than the other. You can push them in & one side was just not making proper contact.

Thanks every one one for the advice.