CTSvOH

2004 CTS-V I have been getting the "Battery not charging" screen on my DIC every morning and when I leave work in the evening, along with the battery acting like it doesn't want to start the car. Took it to Autozone the other day and tested the battery, it was bad, tested the alt., it was good. Got a new battery. Next day the DIC show Battery not charging. Drop the car off at my mechanic to check it out, look at a exhaust leak and CEL. They told me that there is low voltage coming from the PCM to the alt. I believe he said there was 3v when it should be 8v. They suggested I get a new PCM and Flash since they don't know if it's a bad PCM or needs to be re-flashed. Or I could just re-flash and see if that works but if it doesn't I will still have to pay to have the new PCM flashed. I have no idea if there is an aftermarket tune on the car or if anything in the PCM has been messed with. I'm trying to figure out what will be the best way to go at this? Could I take the car to someone that does tunes and see if there is an aftermarket tune? Or buy the PCM myself and have it flashed and install it myself. Thanks for looking.

Mercier

iTrader: (15)

While I'm sure it's possible, that is the first time I've heard that diagnosis. Interesting. I would very carefully clean all the grounds and then pull the connectors off the PCM and see if any corrosion there before I bought a new one. Then check resistance across that wire from the PCM end pin to the alt connector pin.

05CTSV

iTrader: (16)

Do you have headers or stock exhaust manifolds? A few others on here have had the battery cable that runs to the alternator come in contact with the headers and cause similar issues. I only bring this up because you mentioned exhaust leak. Check the cable going from the alternator to the battery. It routes from the starter, up over the bell housing, and clips to the motor mount bolts. If those clips break, the cable can touch the headers, not sure about stock manifolds if you have those.

CTSvOH

Thanks. I will check the grounds. The tech told me that was no corrosion on the PCM or any of the connectors.

I am not 100% sure but I do believe the manifolds are stock. As for the exhaust leak, there were 3 bolts that where broke off on the manifolds. 2 on one side and 1 on the other side. I am having my mechanic fix those and I will ask him to look at that cable. Thanks.

ls1247

iTrader: (2)

You can buy a replacement PCM with a stock tune to your VIN# for 100 bucks off ebay. Once you install it, you will have to do a PCM relearn on the car before it will run. They will send you the directions...follow them to the letter.

After installing mine and doing the PCM relearn, I had a SES/CEL from second one so without having any sort of tuner/code checker I went to my local autozone so they could check the codes for me. The code came back as a downstream oxygen sensor but after dicking with it off and on for a couple of months, my friend checked the code with his device and it seems autozone's code checker gave me the wrong code. There's also a crank sensor relearn process that may or may not need to be done after a PCM replacement and after I did that, the light went away.

Don't always trust the autozone code reader.

CTSvOH

Thanks! I'll check eBay out and see what I can find. CEL on my car turned out to be because someone before me removed the cats. So I guess I'm going to get that code deleted sometime in the future so I don't have to look at that light all the time.

CTSvOH

I am at my wits end with this Battery Not Charging coming on the DIC and battery light on the dash. Here's what I've done so far:
Replaced the ECU as suggested by my mechanic, approved reman ACDelco alternator, ACDelco belt tensioner, and new belt. After throwing those parts at it nothing has worked.

I checked the grey and orange wires going to the alternator and they are getting continuity through them. I checked this by using a power probe 3 and a test light. I unplugged the ECU and ran power through it from the ECU end and used the test light on the alternator end. Also with the key on I checked this wires and the orange wire is getting 10.3v and the grey is 0v.With engine running the orange wire dropped down to 8.Xv and the grey was still 0v. The power wire going to the back of the alternator is getting the same voltage that the battery has. Also the DIC is showing the same voltage as the battery and my power probe shows.

When I start the car, voltage is around 11.8 and it will stay that way until I rev the engine past 3,000 RPMs. After it gets to 3,000 RPMs the battery light goes out and the Battery not Charging goes out on the DIC and the voltage goes up to 14.5. I am getting that same read out at the battery and with my power probe.

Somewhere in the system there is not a signal telling the alternator to charge until the RPMs go up to 3,000 and then it maintains the voltage at 14.5. Does anyone have any other suggestion on what I could be forgetting to check? Side note, I still have to get the Crankshaft variation relearn done from where I replaced the ECU. I don't know if this would have any affect. I will be getting that taken care of in the next few days.

heavymetals

iTrader: (3)

I assume you have cleaned every ground connection in the engine bay, the one under the hood support strut being #1.
Above the starter #2.
Near radiator driver side (frame) #3.
If that doesn't fix it, you might try replacing the alternator plug as engine vibration can break the wires inside the connector.
http://www.ebay.com/itm/271528807301...%3AMEBIDX%3AIT
Last, get the alternator rebuilt by a quality shop, stay away from "replacements".

CTSvOH

I haven't checked the ground by the starter. I'll have to do that. Thanks for the info. The eBay link doesn't work.

heavymetals

iTrader: (3)

try this:
http://www.ebay.com/itm/271528807301...%3AMEBIDX%3AIT

CTSvOH

I went through and checked all grounds. The ground by the fuse box wasn't getting a great connection so I cleaned that up. All the others were good. Unfortunately that did not help with my problem.

Anthony Toal

well you can check the alternator by removing the negative terminal on the battery, old school trick there. Also, I am not sure if our cars have them, but I know some may have a current sensor.

BudRacing

iTrader: (3)

Batteries themselves can be finicky and are replacement items anyway. How old is yours? What is the voltage when the car is off?

CTSvOH

I replaced the battery back in June because it wasn't holding a charge. The battery is at 12v when the key is off.

CTSvOH

I believe I have fixed my problem. Took the car to a tuner today to have some CELs deleted for my cats being removed. When he pulled up the trouble codes there were two codes for the L and F terminals (I believe) that had not been showing up on other scanners. He's scanner was saying that they were old codes that have passed and failed system checks. After deleting those two codes the battery is now charging. Man was this whole ordeal a headache. Weird those codes did not show up on other scanners. Good riddance to that problem. Now on to some other little problems.

CTSvOH

Took me a while to get to this but I've been determined to figure something out. The day after I got home the damn battery not charging indicator came back on. So I decided to wire in a new plug to the alternator. I cut the wires at the ECM and ran them from there to the alternator with a new plug. Wouldn't you know it that still didn't work. So I said F it and ran a wire to the alternator from a fuse tap in the fuse box that is switched on when the engine is running. Problem fixed. battery charges all the time now.

BudRacing

iTrader: (3)

What gauge wire did you use? Isn't this effectively one length of the "Big 3" upgrade?

CTSvOH

I used 14 gauge wire. I'm not sure about the Big 3. Doesn't that have to do with the power wire from the battery? I basically replaced the generator turn wire running from the ECU to the alternator with a wire running from the fuse box to the alternator. Now when the engine is running there is a signal going to the alternator telling it to charge the battery.

BudRacing

iTrader: (3)

The Big 3 includes upgrading the charge wire from the Alternator directly to the battery--often with a 100-150A fuse depending on the demands. The other two wires are grounds--one from engine to chassis and one from the battery (-) to chassis. It sounds like your swap was more of a signal wire than a charge wire? If it's the actual charge wire, 14 gauge is not enough. 8 gauge is probably the smallest I'd go, but 4 or 2 gauge wire is most common as an upgrade. This is also done as a piggy back so you're not eliminating any of the stock wiring, just adding to it so that electricity has a path of lower resistance. It also helps with dimming during high load usage (headlights on, turn signal flashing, stereo up, AC blasting, etc.).

Anthony Toal

Just out of curiosity, where in the fuse box did you run this wire? I am wondering if you just found your issue by jumping the original wire that gives you your signal that the battery is charging and no alarms/errors