Refer to
Circuit Description
The PCM continuously monitors the system voltage. The system voltage
information is taken from the PCMs ignition feed circuits. Since voltages
below 8.0 volts or above 17.1 volts, could cause improper
system operation and/or component damage. Class 2 Serial Data is shut
down when system voltage is below 9.2 volts or above 16.0 volts.
A scan tool will not display data if system voltage is outside this
range. Because of this, use a DMM in order to monitor system voltage
when checking to see if the fault is currently present.
Conditions for Running the DTC
The engine is operating.
Conditions for Setting the DTC
The PCM senses system voltage above 18.0 volts for 2 seconds.
Action Taken When the DTC Sets
• | The PCM stores DTC P0563 in the PCM memory when the diagnostic
runs and fails. |
• | The malfunction indicator lamp (MIL) will not illuminate. |
• | The PCM will record the operating conditions at the time the diagnostic
fails. The PCM stores this information in Failure Records. |
• | The PCM disables most outputs. |
Conditions for Clearing the MIL/DTC
• | A History DTC will clear after forty consecutive warm-up cycles,
if this or any other emission related diagnostic does not report any failures. |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing
the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing
the module. Ensure that the gaskets are installed correctly. The
gaskets prevent water intrusion into the PCM module.
• | Check the generator voltage sense circuit for high resistance
or loose connections. These could cause an intermittent overcharging condition.
Refer to Charging and Starting for circuit details. |
• | Using Freeze Frame and/or Failure Records data may aid in locating
an intermittent condition. If you cannot duplicate the DTC, the information
included in the Freeze Frame and/or Failure Records data can aid
in determining how many miles since the DTC set. The Fail Counter
and Pass Counter can also aid determining how many ignition cycles
the diagnostic reported a pass and/or a fail. Operate the vehicle
within the same freeze frame conditions (RPM, load, vehicle speed,
temperature etc.) that you observed. This will isolate when the DTC
failed. |