Powertrain Diagnosis

Schematic:

The ECM monitors ignition voltage on circuit 339 at all times with reference to ECM case ground when the engine is running. Ignition voltage from circuit 339 can be read on the Scan tool as IGNITION 1 voltage. DTC P0563 sets when the ECM detects high system voltage above a calibrated value outside of the normal charging system voltage range.

DTC PARAMETERS
DTC P0563 will set if ignition voltage is greater than 16 volts when:
^ Condition exists for longer than 200 ms
^ Engine running greater than 3 minutes
^ Vehicle speed is present

DTC P0563 diagnostic runs continuously with engine running and vehicle speed present.

P0563 is a (type D) DTC

DIAGNOSTIC AIDS
To locate an intermittent problem, use Scan tool to monitor IGNITION 1 voltage with engine running at 1300 RPM. With all accessories On or all accessories Off, charging voltage should be in the range of 12.5-15.5 volts.

With engine Off, compare IGNITION 1 voltage on Scan tool with actual battery voltage with a DVOM. If readings do not fall within ± 0.2 volts, check circuit 339 and bolts for ECM case ground for corrosion and tightness.

DTC P0563 could set with ignition On and battery charger connected.

Perform a charging system test. Refer to "Starting and Charging Section". Testing and Inspection