Hi there, I'm having strange electrical issues and wondering if someone here has some suggestions. Symptoms:

- Warning: Check Battery / Alternator light has come on sporadically for months. Happens once every 5 to 10 times I start the car. If I stop and re-start, the message goes away.

This morning for the first time many more things went wrong:
- Exterior Temp Sensor Warning, beeps every 30 seconds or so
- Warning: ABS failure + flashing lights
- Warning: PSM failure + flashing lights

When I stopped the car, it refused to start. I had a new Interstate battery installed this summer. I had a new battery-alternator cable replaced under warranty and part of a factory recall this spring.

The battery was almost dead, yet it had been fully charged just a few hours prior using my Porsche brand dual-mode trickle charger... it had been charging for days... and now my 911 would only make clicking noises when I tried to start it. I called AMA for a battery boost and potential tow (since my certified pre-owned warranty has recently expired)... the boost brought it back to life and I drove straight to the dealership. They seemed perplexed and will spend a few hours to diagnose the issue.

Alternator? Computer? Cabling? I'm inclined to think it's a faulty alternator, but I'm no expert.

The car is a 2005 C2S and it rocks otherwise!

Thanks

 

Do a quick charging test (no-load and load tests). It sounds like your alternator isn't charging your battery.

Some Schumacher battery chargers also have an alternator test switch. Mine does and it makes things convenient.

Good luck

 

The alternator cable harness has a known issue. With age and heat from the engine bay, the resistance of the original cable increases. This causes a voltage drop from the alternator to the battery. Bottom line the battery does not see a full charging voltage.

Check the voltage output at the alternator. Check again at the battery. If the voltage drops more than 0.5V, consider having the alternator battery harness changed out to the updated version.

Another thing to check is your battery's age. Your car is a 2005. How old is the battery?

 

I would also have the battery checked. I had a similar issue and the culprit was the battery.

 

[QUOTE=kellym;3974383]Hi there, I'm having strange electrical issues and wondering if someone here has some suggestions. Symptoms:

- Warning: Check Battery / Alternator light has come on sporadically for months. Happens once every 5 to 10 times I start the car. If I stop and re-start, the message goes away.

This morning for the first time many more things went wrong:
- Exterior Temp Sensor Warning, beeps every 30 seconds or so
- Warning: ABS failure + flashing lights
- Warning: PSM failure + flashing lights

When I stopped the car, it refused to start. I had a new Interstate battery installed this summer. I had a new battery-alternator cable replaced under warranty and part of a factory recall this spring.

The battery was almost dead, yet it had been fully charged just a few hours prior using my Porsche brand dual-mode trickle charger... it had been charging for days... and now my 911 would only make clicking noises when I tried to start it. I called AMA for a battery boost and potential tow (since my certified pre-owned warranty has recently expired)... the boost brought it back to life and I drove straight to the dealership. They seemed perplexed and will spend a few hours to diagnose the issue.

Alternator? Computer? Cabling? I'm inclined to think it's a faulty alternator, but I'm no expert.

The car is a 2005 C2S and it rocks otherwise!

Either a dead cell in the battery or, more likely, the alternator is going/gone. If you can start the car, check alternator out put (if the alt/bat harness was replaced it's not likely the harness causing the voltage drop.) If the engine will not start check the battery for a dead cell either at home if have the equipment, or at the place you bought it. If it checks out you need to have the alternator bench tested to confirm it's the problem.

 

Just a quick update in case anyone is interested. It was the alternator. I already put in a new battery and new battery-alternator cable, and the dealership confirmed the alternator was faulty. Works good now, although it's $1,600 later...

 

Painful

 

Cool. Problem solved---congratulations.

For everyone else, IMO, i believe that without much mechanical skills, anyone can replace their alternator. Expect about $175 for someone to rebuild it.

 

Would you mind posting you mileage?

 

Sure, it has just over 30,000km which is 18,700 miles. But it's a 2005. Still, pretty early for an alternator to go in my opinion.

I wish I'd known the alternator is easy to replace, I could have done it myself or with a friend's help. I took it to the dealer because I know electrical problems can sometimes be very hard to diagnose. Peace of mind that it's fixed again at least.

 

Yours is one of the lower mile failure. They average around 50k iirc. Mine failed a few weeks before yours (@ 56k miles).