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Discussion Starter · #1 ·
A few days ago I had a situation where my car's engine abruptly shutdown (in stop and go traffic luckily). The check engine and battery lights came on and were lit on the dash at the same time. I had to turn off the AC (it was close to 100F that day) and shift into park and push the start button again. The lights did not come on again. I hooked up a handheld scanner to the OBD2 port and no engine DTC codes were found. However I did run a battery and alternator test using the scanner, it says the battery voltage is below limit at 11.8 volts and that the alternator charging voltage is not within limits. Has anyone else experienced this? Can someone hook up an OBD2 scanner to their car and run a battery test? I have a 2015 sGT with all the tech options. Could it be that the scanner does not know how to handle the i-ELoop system and thinks there are faults?
 

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It might indicate a problem with your alternator. The OBD scanner doesn't actually diagnose the car. It only shows you PID values and DTCs. The errors are from the car's computer. Could you post the DTC's that you're getting?
 

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Discussion Starter · #3 ·
I'm not getting any specific DTCs. My handheld OBD2 scanner has a battery and alternator test mode, it reads a PID of 11.8 VDC for the battery and thus says it is low and the voltage values it reads for the alternator (I'm assuming these are PIDs as well) vary between 12.35 to 12.5 VDC and the scanner says this is below the acceptable limit for charging. For the alternator test, the scanner has me turn on the headlights and engine and rev up to 2K RPMs while it reads the alternator voltage.
 

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hello,

Your alternator voltage 2K rpm should read at least 13.5V if not more.
It looks like you have a problem with the alternator. It does not charges the battery -or very little.

Giora
 

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The i-Eloop system does do something with battery diagnostics, but not sure what. When I last had my 2014 sGT at the dealership for the oil change and such, they mentioned that the i-Eloop system keeps them from determining if the battery is operating within spec when they do their 30-point (or whatever) check on the car as part of the service. I didn't think to ask what specifically it throws off.
 
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