GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series Motorhome (Cutaway) C4/C5 🢒 DTC 🢒 DTC P0563

Circuit Description

The powertrain control module (PCM) continuously monitors the system voltage. The PCM monitors the system voltage to make sure that the voltage stays within the proper range. If the PCM detects an excessively high system voltage, DTC P0563 will set. A high voltage condition may cause a stalling condition or other driveability concerns.

Conditions for Running the DTC
    • The engine run time is more than 20 seconds.
    • Engine running above 1200 RPM.
    • Vehicle speed above 8 km/h (5 mph).

Conditions for Setting the DTC
    • The PCM senses the system voltage is above 19 volts.
    • All of the conditions are present for 5 seconds.

Action Taken When the DTC Sets
    • The PCM stores DTC P0563 in the PCM memory when the diagnostic runs and fails.
    • 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.
    • The transmission defaults to a predetermined gear.
    • The torque converter clutch (TCC) operation is inhibited.
    • The instrument panel cluster (IPC) displays a message.
    • The malfunction indicator lamp (MIL) will not illuminate.

Conditions for Clearing the DTC
    • The Conditions for Setting the DTC are no longer present.
    • A history DTC will clear after 40 malfunction free ignition cycles.
    • The powertrain control module (PCM) receives the clear code command from the scan tool.

Step

Action

Value(s)

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Engine Electrical Connector End Views

1

Did you perform the Engine Electrical Diagnostic System Check?

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Go to Step 2

Refer to Diagnostic System Check - Engine Electrical

2
  1. Turn OFF all the accessories.
  2. Measure the battery voltage at the battery using the DMM .
  3. Operate the engine speed above 2000 RPM.

Is the battery voltage less than the specified value?

19 V

Go to Step 4

Go to Step 3

3

Replace the generator. Refer to Generator Replacement .

Is the action complete?

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Go to Step 5

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4

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls-8.1L.

Is the action complete?

--

Go to Step 5

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5
  1. Select the diagnostic trouble code (DTC) option and the Clear DTC Information option using the scan tool.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the DTC reset?

--

Go to Step 2

System OK