Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Ignition OFF, measure and record the battery voltage at the battery terminals.
Verify the battery voltage stabilizes between 12.4 and 12.8 V within a few minutes of turning the ignition OFF.
- If battery voltage is less than 12.4 V or more than 12.8 V
  Refer to Battery Inspection/Test .
- Go to next step: If battery voltage is between 12.4 and 12.8 V
Engine running, headlights ON, measure and record the battery voltage at the battery terminals.
Verify the voltage is at least 1 V greater than the voltage measured in step 1, but less than 15 V.
- If the voltage is not at least 1 V greater than the voltage measured in step 1 or is greater than 15 V.
  Refer to Charging System Test .
- Go to next step: If the voltage is at least 1 V greater than the voltage measured in step 1, but less than 15 V.
Verify the appropriate control module battery voltage and ignition voltage parameters are available in the scan tool.
- If parameters are not available in the scan tool
  Refer to Circuit/System Testing
- Go to next step: If parameters are available in the scan tool
Verify the appropriate control module scan tool battery voltage and ignition voltage parameters are within 1 V of the battery voltage.
- If not within 1 V of the battery voltage
  Refer to Circuit/System Testing
- Go to next step: If within 1 V of the battery voltage
All OK.