"Brake" light and "Battery" light on.

[Odakrem]

Hello all.

I have an 05 WRX and both of said lights are on. I just replaced my battery that did not change anything. I also checked my fluids and did a visual inspection of my brakes and everything seemed peachy. Anyone have any idea on what's up?

[michaelwfox]

Pull the negative cable from the battery for 5-10 minutes. When you reconnect it the ECU should have reset. If it doesn't then there might be another problem, which I have no idea about.

[SD_GR]

It's a charging problem. Suspect alternator.

[Ingo]

Check voltage at battery with engine off and engine running. Should get up to 14.5 volts with engine running. Engine off = 12.5 to 13.5 V (for a charged battery) If voltage is not higher when engine is running you will have to check the alternator/regulator (part of the alternator, usually).

[Odakrem]

Alright Ingo, I'll check the voltage tomorrow and post results. Thanks for the quick replys.

[Odakrem]

Ok does any one have any input?

I replaced my battery and replaced the alternator...still have both my "brake and battery" lights still on...any idea?

[SD_GR]

I'd still suspect charging problem. Check voltage (carefully!) across battery terminals with car off vs. car running. Check (carefully!) all harnesses to battery and alternator. All this assumes a good belt and no pulley or tensioner problems.

[Odakrem]

Checked voltage with DMM with car off I was at 12.65 with car on I was at 14.04.

Car has new battery and alternator...any ideas?

[Ingo]

I just went and checked mine for comparison: Voltage with engine running was 14.75 (engine cold @1500-2000rpm), after shut down it was reading 12.9 and slowly dropping. I did not get a reading before starting because sitting against the wall and had to back up to get under the hood. Bottom line, your charging voltage looks still low. I had a problem once with my BMW motorbike: the ABS light would stay blinking with no other indication of a problem, other than weak starting, was a bad battery. The ABS electronics turned out to be VERY sensitive to low batt. Maybe the subie is like that, don't really know if so. Anyways, again, your batt volt seems fine, charging seems low. The numbers above are from my 2009 WRX.