Just bought a 2006 m35, battery and brake light on?

[Brian35XR]

Hi all. I come from g35driver.com as I use to own a 2004 G35 but recently bought a 2006 M35x with 125k miles on it and like it a lot better. Nice community here I been reading and learning alot. However I have a small problem. The car has been running smoothly however recently I went to go start it in the morning and the seats and the steering wheel didn't adjust, they just stayed in their complete pulled back/upright positions so I had to readjust them myself. Then I noticed the Brake and Battery Light were on. They went off after about 5 minutes and haven't come back on since yesterday but I was reading this is indicative of an bad alternator... is this always true?

Also my car is throwing a C1185 code. The dealer says I need a new Cruise Control module but my cruise control works completely fine! I read any sort of problem can make that code come up. Any idea on that?

Thanks all!

[Brian35XR]

Forgot to add me and my friend tested the battery with a mulimeter and it's around 12.2v with the car off. Goes up to ~14v with the car on but when I put the car under load (lights on, AC on, heated seats, music loud, rolling windows up and down) it drops back down to around ~12v. I think this is normal but he says it should stay up at 14 always. Any comment?

[kmiles]

Here is what my alldata account says about C1185:

C1185: ICC Sensor Integrated Unit Circuit (With ICC)

INSPECTION PROCEDURE
1. CHECK SELF-DIAGNOSIS RESULTS
Check self-diagnosis results.

If the self-diagnosis displays: ACC CONT

Is above displayed on the self-diagnosis display?
YES >> GO TO 2.
NO >> INSPECTION END
2. CHECK ICC SENSOR INTEGRATED UNIT CIRCUIT

1.Perform ICC sensor integrated unit self-diagnosis. Repair or replace items indicated, then perform ICC sensor integrated unit self-diagnosis again. Refer to ACS-29, "TROUBLE DIAGNOSIS - GENERAL DESCRIPTION".
2.Perform ABS actuator and electric unit (control unit) self-diagnosis. OK or NG

OK >> INSPECTION END

NG >>

•Repair or replace malfunctioning components.
•Perform the self-diagnosis, and make sure that the result shows "NO DTC IS DETECTED".

Note that ICC = Intelligent Cruise Control. One thing that you might look at is the ICC Brake switch, and whether it is either stuck or failed. There is a link on this site to the service manuals and you'll want the ACS section. It has all of the troubleshooting steps for the various cruise control components.

[The00Dustin]

Pretty sure the voltage should stay up with the alternator running. Definitely less expensive to replace the alternator than the ICC stuff, and could solve both problems. I'd replace the battery first just because of the odd things I've seen with weak batteries in these cars. For instance, I wouldn't be surprised to find that a weak battery caused an ICC DTC to trip, and I certainly wouldn't be surprised to find that a weak battery put enough additional load on the alternator that it couldn't keep up with everything else running too.

ETA: Also, I think your battery should show 13.1V when the car is off, so 12.2V is almost low enough to indicate a bad cell in the battery, which would be even more likely to cause problems than just having one that doesn't hold a charge well.

[svard75]

If the battery is original replace that first. Our cars are notorious for tripping other DTC's when it's simply the battery. I don't think it's unheard of for the voltage to drop down while under load especially if the car is idle. Remember the alternator needs to spin to generate more power so try loading it up again and keep the RPMs around 2k then measure the voltage.