Pinpoint Test A : System Voltage High: Notes
Diagnostic Overview
Diagnostics in this service information assume a certain skill level and knowledge of Ford-specific diagnostic practices. Refer to Diagnostic Methods in Service Information for more information.
Refer to CHARGING SYSTEM for schematic and connector information.
Normal Operation and Fault Conditions
With the engine running, the charging system supplies voltage to the battery and the vehicle electrical system through the high current BJB and battery B+ cable. The voltage that is supplied to the vehicle electrical system is used for the operation of the various vehicle systems and modules. Many modules monitor this voltage and if it rises above or below their calibrated setpoints, a DTC sets.
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0563 | System Voltage High | This DTC sets if the PCM detects a voltage from the charging system greater than 15.2 volts with vehicle speed above 8 km/h (5 mph). |
| P1397 | System Voltage Out of Self-Test Range | The PCM sets this DTC if the voltage rises above or drops below the calibrated setpoint. This DTC can also set if the vehicle has been recently jump started or has had a discharged battery. |
| U3003:17 | Battery Voltage: Circuit Voltage Above Threshold | Sets in the BCM when the BCM detects that battery voltage has gone above 15.9 volts from the voltage supply circuit. |
Possible Sources
- Battery
- Engine, generator and battery grounds
- Fuses
- Generator
- PCM
- Wiring, terminals or connectors
Visual Inspection and Diagnostic Pre-checks
- Verify the fusible links.
- Inspect for loose or corroded connections.
- Inspect high current BJB for loose or corroded connections.