Check VPWR During Cranking
Purpose:
To verify PCM power-up during cranking. Lack of power to PCM can cause a no start condition as well as fault code loss. Scan tools often require a minimum system voltage of 9.5 volts to avoid resetting.
Recommended Procedure:
Connect the OBDII Scan Tool to the data link connector (DLC) under the dash. Access VPWR PID on OBDII Scan tool and monitor while cranking the engine.
Possible Causes:
- Low battery voltage.
- Charging system problem.
- Power circuit and ground faults to the PCM.
Note: Battery voltage below 9.5 volts can cause the Sacn tool to reset. If the OBDII Scan Tool resets during a self test or while PID monitoring, it may be necessary to install a battery charger to maintain the correct voltage.
Tools Required:
Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent Scan Tool.
- Check Fuel Pulse Width (FUEL PW) While Cranking
- Check RPM Signal While Cranking
- Monitor ICP While Cranking
