Circuit/System Verification

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 .
- 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 .
- 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
- 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
- If within 1 V of the battery voltage
All OK.