Check Vehicle Power (VPWR) During Cranking Test: Purpose

WARNING: This page is about a different car, the 2008 Ford Pickup, 2008 Ford F550 Super Duty, 2008 Ford F450 Super Duty, and 2008 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The purpose of this test is to verify PCM power during cranking.

Scan Tool - Data List Monitoring

NOTE: The 8 volt specification represents the minimum battery voltage required for engine starting. Greater than average crank times are encountered if the battery voltage is less than 9.5 volts. If excessive crank time is a concern, verify battery voltage is greater than 9.5 volts.

NOTE: You may need to use an outside power source for the scan tool.

The scan tool may reset below 9.5 volts.
Select the parameters indicated from the scan tool parameter list and monitor while cranking the engine.

Parameter	Specification	Measurement
VPWR	8 volts minimum

If a low voltage condition is present, check the battery, charging system or power and ground circuits to the PCM.