GXP25

iTrader: (3)

When they changed the battery in my car, I thought that maybe they messed around with it so I untapped it and repositioned it.

I don't think mine is malfunctioning because I measured the voltage across the alternator terminal and noticed that it was lower than it needed to be when I was having my issues.

If it acts up again I'll just replace it (the alternator).

Ill_Born_ss

SO simply replacing an alternator or a battery or a computer without proper testing can lead to the mud in your face when you give up and have it tested properly and they tell you it is the current sensor that is failed/incorrect.

blkchevyz

where is that sensor? i'm still thinking my issue is the alternator since replacement fixed it before, but i might throw one of those on as well.
alternator has a lifetime warranty so i'm not worried about that lol

blkchevyz

also does everyones lights dim when rolling up the windows? probably a stupid question but none of my other cars were that noticeable.

neilownz

I've thought about relocating the battery to the trunk and putting something bigger in before, but now it's like -20 outside and I'm using my truck.

Ill_Born_ss

You can get the sensor (#5 above) at your GM dealer (I would recommend calling a dealer with your VIN# and getting the latest P/N for your application FIRST)

OR
http://www.rockauto.com/ P/N search 5S6706

ALSO you should remove and clean and protect (die-electric grease) all the GROUNDS.

Here is some help: http://www.gmls4.com/index.php?topic=1412.0

blkchevyz

thanks for the info.
if i had a scanner hooked up to the computer, would the displayed voltage be driving off that sensor? if so would i see a difference in the the gauge vs the scanning voltage?

Ill_Born_ss

The sensor operates on a pulse width and with each pulse, it in turn sends a given voltage to both the BCM/TCM and they tell everything what to do and how to react to the given conditions.

As sensors get old, contaminated or what not they either slow down or send incorrect data/voltage to the computers. Now some of these cars had an improper P/N installed when built and they are/were so close in the required voltage/info that the owners got some use out of them prior to failure. That is why I recommended you call a dealer with your VIN. and they can tell you the current P/N and you can compare it with the one installed on your car.

As far a using a scanner, yes if you can see the actual pluse width voltage and then compare it to the required #`s for your car. It is something like .0- .03 or .2- .5 volts (examples only not the actual for your system) That I would have to look up to know for sure. Again maybe your dealer could tell you for sure.

blkchevyz

So I guess you have to cut off the ground connector for the battery to get that sensor off?

Ill_Born_ss

The manual says to remove the neg cable and slide it all the way off the bottom. We usually just cut off the connector/ terminal and install a new one. Be sure to face the tail of the sensor away from the battery terminal.

blkchevyz

thanks.

blkchevyz

dealer will only sell a full ground harness... do you just use a universal terminal?

91parkave

iTrader: (4)

The universal terminals work , I was using the Autozone gold terminals for neg and pos when I ha my battery up in the front of the car.

blkchevyz

thanks.
cutting that off and putting a new one on, seems like a ton less work than chasing that cable and pulling it out of the wire looms.

blkchevyz

swapped that out, now I have a service vehicle soon notification... first time I've seen that..\
scanned it and of course that doesn't show code for it.

GXP25

iTrader: (3)

I've had that same notification on my vehicle for a couple years now. I've just been too busy to take it to the dealership to spend some money to get it cleared.

If you figure it out please let me know.

Ill_Born_ss

Glad to hear you got the sensor changed. You have made the repair. As for the "service vehicle soon" light yes you need to find a scanner/reader that can show all modules to clear/reset the history/ pending codes held within the units. Your ABS module will at least be holding a low voltage code and your BCM will be holding all your low voltage and battery disconnects history. You may even be experiencing no low cooling fans due to the BCM calling on electrical load shedding (sets it to ACTIVE) when it sees low voltage. A simple CODE clearing or Battery Disconnect does not remove this info from other modules.

If you drop by your dealer and ask if they can read and clear all codes for you, they may do it! Just say I want to see what history there is and clear it prior to bringing it in for troubleshooting/repair. Want to see if the symptoms re-appear.

Be sure your battery is fully charged, I recommend a trickle charger for at least 12-24 hours.
Here is something you can try as it has been rumoured to me that sometimes they cannot clear the BCM or reprogram it due to some gremlin in the system caused by the grounds. ( if a ground other than the main battery ground is disconnected while the main battery ground is hooked up it will cause the BCM to search for an alternate ground)

Here is what to do:

With the doors closed and e-brake set

Turn off ignition and remove the key

Remove the fuses that power up the following modules/components for a min. of 2 minutes

1-BCM
2-EBCM
3-ECM
4-IS LPS (located in the left IP fusebox)
5-TCM

Now open and close the drivers door. Allow enough time for the RAP (retained accessory power) to turn off.

Now re-install the fuses then start the car. This may clear your light but the info is more for you incase the dealer cannot get into the BCM to clear/re-program.

blkchevyz

is that something a tech2 will pick up?

i think i did do that, i un did the chassis ground right by the battery when i was cutting the wires. i started hooking the battery up then noticed i didnt connect that back up.

Ill_Born_ss

Yes the tech2 has to be used if the BCM has turned/switched the load shedding mode to "active"
It may be able to be reset by clearing it, but there is a greater possibility it (BCM) has to be re-flashed (which involves re-flashing all modules if the BCM actually had/has searched for the alternate ground.
Good news is you have no codes so your system is most likely repaired and just requires a reset. If by any chance the tech says you need a new BCM as they cannot re-flash tell them to look up TSB 09-08-47-001a (unable to reprogram BCM, programming did not complete) THERE IS NO NEED TO REPLACE IT!

blkchevyz

thanks for the info.