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Can someone suggest a scan tool I can purchase that will
allow me to read charging system codes?
I have a '19 Z51 2LT A8 and I am not sure if have a charge
system problem or not. The battery volt display on the DIC
reads (while driving) anywhere between 12.5 V to 15.3 V
and this doesn't seem normal to me. I replaced the battery
last January '21 as I deemed it to be failing since it
dropped to 11.2 V just with the headlights on.
Can't be positive that it would read them but I would assume it would, we had a check engine light on my wife's vehicle last week, went to Walmart and bought a Hyper Tough code reader for $19.95, plugged it in and said her thermostat was stuck open. I replaced the thermostat and reset the code and check engine light went off. If it would do that, would probably do what you want to do, handy to have around anyway. Might give a detailed description of what it does on Walmart's website or Hyper Tough's website.
You are seeing normal charging voltages , on a C7, which has a variable charging rate dependant on load and battery voltage . Sometimes mine will start out at 15. 0 volts just after starting on a cold morning and then drop down to as low as 12.8 after a few miles which is normal fully charged batter voltage for an AGM battery which I have
If you have an issue the car will tell you with a CEL and a check charging system message. No message , no CEL , = no code
Also you don't check charging system with an OBD II code reader , all u need is a simple volt meter or GM's GDS2 diagnostic software
Ebay has a number of cheap, little, plug-in volt guages, with cig-lighter plug that can be stuck in the center-console outlet if you just want something quick and easy on the fly once in a while.
You are seeing normal charging voltages , on a C7, which has a variable charging rate dependant on load and battery voltage . Sometimes mine will start out at 15. 0 volts just after starting on a cold morning and then drop down to as low as 12.8 after a few miles which is normal fully charged batter voltage for an AGM battery which I have
If you have an issue the car will tell you with a CEL and a check charging system message. No message , no CEL , = no code
Also you don't check charging system with an OBD II code reader , all u need is a simple volt meter or GM's GDS2 diagnostic software
Dave
Thanks Dave, I have a Fluke DVOM and I hooked it up to the charge port by the battery. I drove around for a couple
hours monitoring the volts on the DIC and comparing it to my meter. I found the DIC to be within - 0.1 V to - 0.15 V of
my meter. My '19 model was an early production 3/18 and the battery was code dated 1/18, so it was exactly 3 yrs.
old when I replaced it. I had expected to get 4 or 5 yrs. out of the original battery. I thought that the battery was
possibly damaged due to overcharging as I was getting DIC volt readings of 15.4 which was 15.5 at the battery.
My old school thinking is 14.8 V is the max one should see to avoid burning out bulbs and overcharging batteries.
So I replaced my battery with an AGM battery from Wal Mart (yes, Wally world, I have used their batteries for
years and never had a problem with them) it has a 4 year free replacement warranty
@Makitso I feel the oem battery is woefully way to small at 550 amps given all the modules etc in the car , my battery also started giving me issues at 3 years and I did not want to believe it .
Slow starting after sitting, guage always above 14.9 , always having to use the trickle charger if I left it parked for a while and the wierd electrical gremlins that would show up as modules would not boot up
Then one day at the track was the straw that broke the camels back , I had to keep moving up in line and on the 3rd start it almost did not kick over
Next day I searched for the biggest battery I could buy that fit in the hole . I found the platinum AGM with 960 AMPS , 760 CCA and have never looked back , no more trickle charger , starts like a jet engine no matter what but..... I still get the crazy voltage swings which is just part of GM's charging strategy for these cars as the ECM controls the Alternator
To add insult to injury, my wife recently was laid up for a period of about 8 weeks. Her AMG sat in the garage the whole time . When she went back to work it fired right up ..... lol lol 😆
You will be able to read all of the codes on the car, send commands to modules so you can do diagnostics. Tool is basically a clone of the MDI module used by GM dealerships.
You will be able to read all of the codes on the car, send commands to modules so you can do diagnostics. Tool is basically a clone of the MDI module used by GM dealerships.
Bill
Yep this is the one I have , works great but getting the software loaded and running is a real challenge. And unless you have a background in computers and VM ware be forwarned ...there is no customer support as it comes from China and they only will communicate thru email with bad Google translate
be prepared for it because it is NOT plug and play . I have helped no less than 10 people get this software up and running and one where I just could not get the device to communicate
The problem is not the device , the software is old as GM switched to the new CAMBUS standard and GDS2 starting back in 2012 . The software was designed to run on a windows 7 32 bit machine which now is rarer than diamonds . It also wants to run on the 1st or 2nd generation I core 5 processors, anything older or anything newer and it's a crap shoot . After trying to load it on my new laptop without success I bought a older Dell Latitude for 200 bucks On Amazon and with a few changes to the com ports it works great ...
It also comes with TECH II WIN for older GM cars. I am glad I got it running as I have used it on many of my friends cars....
That looks interesting, Bill. I have one of the BlueDriver modules that reads codes for all my vehicles but it does not do programming and ABS activation. The VXDIAG ad you link says you need to buy a subscription for many of the active functions? Is that needed to say, cycle and purge the ABS module? Do you have the ability to do that? How much does a subscription cost?
Oh, I have one of those DieHard AGM batteries and my running volts behave just like the OP's. I posted a thread about this a couple months ago. The consensus is that it is normal even though it behaves unlike any other charging system voltage I have ever experienced. The others are much steadier with not as much total swing. I suspect the ECM is analyzing the battery in real time and adjusting voltage accordingly.
You will be able to read all of the codes on the car, send commands to modules so you can do diagnostics. Tool is basically a clone of the MDI module used by GM dealerships.
Charge system code reader recommendations
