Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC P0563: System Voltage High - ECMDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | P0562 | P0562 | -- | -- |
Ground | -- | P0562 | -- | -- |
Typical Scan Tool Data
Circuit | Short to Ground | Open | Short to Voltage |
|---|---|---|---|
Operating Conditions: Ignition ON, engine OFF. Parameter Normal Value: 12.6 Volts | |||
Ignition | 0.0 Volts | 0.0 Volts | 12.6 Volts |
Circuit/System Description
The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range. If the ECM detects high voltage, DTC P0563 sets.
Conditions for Running the DTC
| • | The engine is running. |
| • | The vehicle speed is greater than 8 km/h (5 mph). |
| • | The system voltage is between 9.5-18 volts. |
Conditions for Setting the DTC
The ECM detects that the system voltage is greater than 16 volts for 1 second.
Action Taken When the DTC Sets
The charge indicator turns ON.
Conditions for Clearing the DTC
| • | The ECM will command the indicator OFF after one trip in which the diagnostic test has been run and passed. |
| • | A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
Diagnostic Aids
A high voltage DTC in multiple modules indicates a concern in the charging system.
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 4.3L (LU3) engine |
| • | Engine Controls Schematics for the 6.6L (LMM) engine |
| • | Engine Controls Schematics for all other engines (w/o LU3 or LMM) |
Connector End View Reference
| • | Engine Control Module Connector End Views for the 4.3L (LU3) engine |
| • | Engine Control Module Connector End Views for the 6.6L (LMM) engine |
| • | Engine Control Module Connector End Views for all other engines (w/o LU3 or LMM) |
Description and Operation
Charging System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
- Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.
- Observe the scan tool ECM Ignition 1 Signal parameter. The reading should be between 12.6 and 15.0 volts.
| ⇒ | If not within the specified range, refer to Charging System Test . |
| ⇒ | If greater than the specified range, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming.
