cgaites

Hi all,

For the first time in seven years of ownership my Carrera has let me down by failing to start. I’m hoping the forum can point me toward the cause so that I can either DYI the repair, or at least minimize the number of parts my mechanic throws at the problem.

Here are the basics about the car:

- It’s a 2010 Carrera
- 3.6L DFI engine and manual transmission
​​​​- Approximately 78K mikes
- The battery is 3 years old

Here’s the behavior it’s exhibiting:
- The engine will crank one or twice when I turn the key
- After the first crank it seems like the electrics are going haywire - light dim and come back on, PCM starts and then goes off, dashboard lights up, daytime running lights come on and go off
- After the second crank it gives up and it just clicks
- Following the start-up attempt the dash gives both ABS and PSM failure warnings

If I keep the key in the accessory position, then everything (windows, PCM, etc.) seems to work fine. Also, if I roll the car down my driveway and pop the clutch the car starts and runs totally fine.

I see the same behavior with both keys, so don’t think it is related to the key batteries. Also, if I try to start the car without pressing the clutch, the car does not attempt to crank, and gives the “Depress Clutch” message on the dash. So, I don’t think it is the clutch interlock (or whatever the switch that detects the clutch is in is called).

Anyone have any idea what to look at from here?

Thanks in advance

Ironman88

Sounds like a weak battery.

ADias

Rodent problem?

cgaites

Thanks guys

The battery seems too new to be the problem, but going to go get it tested later anyway. Fingers crossed that is it.

Don’t see any signs of rodents under the bonnet or hood, but who knows. The car does live in a detached garage, so it’s a possibility that something got chewed where I can’t see it. Will keep looking after I get the battery tested.

Ironman88

Going forward, I would recommend investing in one of these ($35). Reports a variety of conditions to your android or iOS phone via a free app. You can monitor the health of your battery on a continual basis, as well as the charging system of the car.

It also detects (and reports) anomalies with the alternator (overcharging for example) when the car is being driven. The app tracks conditions historically over a rolling 31 day period of time.

https://antigravitybatteries.com/pro...ker-lead-acid/



Battery Tracker for Lead Acid batteries.

anewman

Sounds like the battery to me

cgaites

Thanks everyone. Had the battery tested and it was indeed bad. 37 months old and just out of its 3 year warranty

Oh well. New battery is in, and now the car starts no problem.

ADias

Low batteries trigger out all kinds of gremlins/spurious CAN bus signals causing all kinds of issues; PDK cars often think the transmission is bad with a low battery. Glad it was that simple!

jchapura

Regarding the AG-BTR-2, does anyone have experience with it interacting poorly with a CTEK battery maintainer? When my car is in the garage it is almost always on the battery maintainer.

Ironman88

I have one on my battery along with a CTEK unit. No issues whatsoever.

Antigravity

Hey JChapura,

If you ever have any questions feel free to ask us, our contact is in the signature below.

The Antigravity Battery Tracker only has a 1 mA (milliamp) Draw when connected so it can't play a real part in draining the battery, on the other hand if you have the Phone App on all the time it can drain the PHONE'S battery a little faster because the Bluetooth App is constanly trying to Connect to the Battery Tracker to get its data for you. So best to use the Phone App for the Battery Tracker when you are by the Car and using its features, then turn it off once it downloads it data then you can review all the data anytime but don't have the bluetooth searching to connect if you are not requiring it.

jchapura

Howdy Scott @Antigravity ,

I did write to your corporate info@ email address - no response yet.

My question really isn't about battery drain (car or smartphone) but about your voltage meter interacting poorly with either the battery maintainer or my car (which seemingly has some sensitive electronics) - either getting fried or wonky because your voltage meter and the battery maintainer will be connected and running for a majority of the time (while the car is parked at home).

Antigravity

Hey Jchapura,

Let me know the date you wrote to us... I want to make sure they didn't drop the ball. You should most always get a response withing a few hours except on the weekend when they come back on Monday the emails are quite full on Monday from the weekend.

In any event the Battery Tracker is such a low-draw device that it will not have any effect on the charger at all. It cannot fry anything, or have anything fry it. It is not something that can draw a high current, and it can't short-circuit itself or anything. It simply records voltage at the terminals, and could easily be powered by a 9v battery for over a month by itself

It will actually show the charging profile of the charger itself when the charger is connected to the battery and doing its thing.YOu can see the profile in the History page of the Battery Tracker's App. So rest assured it will not interfer with any Charger or any other part of the battery system. Top right was the Charging profile of an Optimate 5 Amp Charger.

If I didn't get you answered correctly let me know..

jchapura

Thanks for the device info. I emailed yesterday.

jchapura

I installed my new Battery Tracker in the late afternoon yesterday. (I disconnected (and have not yet reconnected) my battery maintainer.)

Interesting behavior - the battery state/percentage (as reported by Battery Tracker) started out in the low single digits. Over a few hours, it rose to 100%. Is that expected behavior? If not, what does it mean?