Circuit/System Verification

Ignition OFF.
Test for 12.4-12.8 V at the battery terminals and record the reading. The battery voltage should stabilize after a few minutes of turning the ignition OFF.
- If not between 12.4 V-12.8 V
  Refer to Battery Inspection/Test
- If between 12.4 V-12.8 V
Engine running, accessories OFF.
Test for 13.4-15 V at the battery terminals and record the reading.
- If not between 13.4-15 V
  Refer to Charging System Test
- If between 13.4-15 V
Verify the engine control module scan tool Ignition 1 Signal voltage parameter is 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.