charging problem
#21
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Here is something directly related to your symptoms.
https://ls1tech.com/forums/ls4-perfo...l#post17510500
scroll down and read about the CURRENT SENSOR
I will see if I can find the TSB
https://ls1tech.com/forums/ls4-perfo...l#post17510500
scroll down and read about the CURRENT SENSOR
I will see if I can find the TSB
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).
#22
When they changed the battery in my car, I thought that maybe they messed around with it so I untapped it and repositioned it.
The TSB I refer to simply states that some models have the improper sensor installed and this wrong sensor gives the wrong info to the other computers and in turn tells components like the alternator to produce less or more than actually required.
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.
This is a really simple sensor and cheap, but you cannot think it is malfunctioning or not it has to be accurate to your system for it to tell the other computers what and when to do it!
Here is a link to an article that will explain the system in brief:
http://www.spectroscopyonline.com/sp....jsp?id=577608
If it acts up again I'll just replace it (the alternator).
The TSB I refer to simply states that some models have the improper sensor installed and this wrong sensor gives the wrong info to the other computers and in turn tells components like the alternator to produce less or more than actually required.
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.
This is a really simple sensor and cheap, but you cannot think it is malfunctioning or not it has to be accurate to your system for it to tell the other computers what and when to do it!
Here is a link to an article that will explain the system in brief:
http://www.spectroscopyonline.com/sp....jsp?id=577608
If it acts up again I'll just replace it (the alternator).
#23
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
alternator has a lifetime warranty so i'm not worried about that lol
#26
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
Last edited by Ill_Born_ss; 12-07-2013 at 06:24 AM.
#27
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?
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?
#28
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.
#30
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.
#36
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If you figure it out please let me know.
#37
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.
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.
Last edited by Ill_Born_ss; 12-30-2013 at 06:57 AM.
#38
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.
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
#39
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!
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!