battery voltage

[tedjan]

when i messure my battery voltage I read 14.4V, reading live data I see 13.1V. On my dash Voltmeter reads 13.1V
Is this normal?
Or have I some resistance somewhere? Relais? fuse?

[steveo]

check all your grounds. i wouldn't stress it though, it's kinda typical.

what's important is that the ECM has about the same reference voltage as any sensor that takes a +12v input, and injectors.

[84Elky]

when i messure my battery voltage I read 14.4V, reading live data I see 13.1V. On my dash Voltmeter reads 13.1V
Is this normal?
Or have I some resistance somewhere? Relais? fuse?
Quite normal. Many if not all of the available GM ADX files, code hacks, etc. incorrectly indicate that Battery Voltage is being reported. However, the real voltage reported is Keyed Ignition Voltage. This ensures voltage is only measured when the key is on -- the only time it is really meaningful to the ECM. In fact, most GM code determines if the key is off if voltage (KIV) is < approx 3.7v).

Can also have similar differences when looking at pump voltage .vs. KIV.