Circuit/System Testing

WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.

Ignition ON, verify that no generator or battery current sensor DTCs are set that would cause a charging system concern.
- If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
Ignition OFF, measure the voltage across the battery terminals. The voltage should read 12.0 volts or greater at room temperature.
- If not within specified value, refer to Battery Inspection/Test .
Connect a carbon pile tester to the battery.
Start the engine and turn all accessories off. Observe the voltage reading on the tester. The voltage should read between 12.6-15.5 volts.
Adjust the carbon pile tester so that the 12 volt current on the APM data list is reading 175 amps.
- If not within specified value, replace the APM.