Haulroad

Get a load of this gang,
I recently came close to ending the wagon's g22/csp sensor/fr charge valve induced hiatus; close being the essential word in that claim. As a result of a healthy dose of aimless thought and effort I was able to get to the bottom of a few headaches. Having missed driving the wagon for a few weeks I began to get a bit antsy as I was buttoning her up. In eagar anticipation to take a dusk canyon stroll, I jumped in the drivers seat, popped in the key and... The battery is dead, really dead. Unfortunately an inconspicuous gps was sleeping in there, plugged in for the whole time and it ate every single once of energy contained in that battery. Being a brand new battery I figured I could save it. I charged it on the least aggressive setting for almost 2 days and sure enough when I got in today the dash lit right up and the gauge read 12v, looks like we're In business; have I learned nothing? I turned the key and absolutely nothing, no turn over, no solenoid, not even a dim of the lights. I'm fairly certain it's not the starter for the one In there isn't more than 2 months old.My best guess is that although the battery can keep the lights on, it doesn't have the ***** to hold any real load. Any Kind of input is welcome, hopefully somebody has some interesting ideas.

amiram

When this happens it causes a lot of fault codes in the vehicle computers ECU TCU etc .... Delete the fault codes

Haulroad

I checked and cleared the ecu when this first happened, unfortunately that wasn't it.

Irish1004

You didn't indicate whether you checked the voltage at the battery (my apologies if you did) but I would check that and assuming the battery is at full charge I'd next check the cable connections and resistance of both cables at battery, starter and ground. Assuming all is well there could it be an issue with the immobilizer? If the battery is still discharged I would give it a full aggressive charge (not a slow trickle charge). A new battery should be able to endure a complete voltage run down and then accept a full charge.

Haulroad

The battery is fully charged, just over 12v iv checked all the starter to battery lines for continuity and all is good in that department. I'm now fairly certin that there's some kind of reset that needs to be done because when you go to start the car it behaves as it would if you weren't in park or you didn't have the brake on or something, you turn the key and basically the ecu won't let the car start for whatever reason. If anybody has any Information on a reset of some kind I think that may be the ticket.

Irish1004

I have heard of a similar situation incident when the car wouldn't start due to a faulty transmission neutral switch that in effect was indicating that the car was in reverse gear when it was actually in park. The indicator on the dash even showed reverse. I'm wondering if you put the car in neutral if that would allow it to start. Might be worth trying?

snagitseven

Unfortunately, clearing fault codes only clears the fault log and won't clear any problems that caused any faults to appear.

hqbmw1@gmail.com

A fully charged 12v battery should have a surface charge of 13.5 to 14.4 volts. Your 12v is not sufficient. Have you load tested the battery? If not and you dont have the equipment to test it, take it into a parts store where they test for free. You are jumping at problems of the ecu or otherwise complex issues without ascertaining the simple and proper steps of troubleshooting. Remember, KISS.

Haulroad

From what I could see on the cluster voltage meter it was just over 12v which equated to 13.2 when I tested it. Figuring it's possible that it just can't hold a load I tried a 14.0v Touareg battery and a 13.8v jeep battery, both yielded the same result, nada. So again I'm pretty sure it's not the battery. I tried about every reset sequence I could find and nothing, I'm hoping it's a relay or something and not the starter.

Haulroad

Also I tried the neutral thing irish1004 and that too was a no go.