Pinpoint Tests: Notes
System Voltage High
Refer to Wiring Diagrams Cell 12 for schematic and connector information.
NOTE:
Diagnostic Trouble Code (DTC) P0563 can be set if the vehicle has been recently jump started or the battery has been recently charged. The battery may become discharged due to excessive load(s) on the charging system from aftermarket accessories or if vehicle accessories have been operating for an extended period of time without the engine running.
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.
Diagnostic Trouble Code (DTC) Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P0563 | System Voltage High | This DTC sets in the PCM when the PCM detects voltage from the charging system greater than 15.9 volts with vehicle speed above 8 km/h (5 mph). |
| P1397 | System Voltage Out of Self-Test Range | If the voltage rises above or drops below the calibrated set point, the PCM sets this DTC. This DTC may also be set if the vehicle has been recently jump started or has had a discharged battery. |
Possible Sources
- Battery
- Generator
- Engine, generator or battery ground
- PCM
- Wiring, terminals or connectors
Visual Inspection and Diagnostic Pre-checks
- Inspect BJB fuse 55 (10A).
- Inspect grounds G105 and G106 for loose, damaged or corroded connections.
- Inspect the high current BJB for loose or corroded connections.