GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2000 🢒 DeVille 🢒 DTC 🢒 DTC P0563 System Voltage High

Circuit Description

The PCM checks the system voltage to make sure that the voltage stays within the proper range. Damage to components, and incorrect input can occur when the voltage is out of range. The PCM monitors the system voltage over an extended length of time. If the PCM detects an excessively high system voltage, DTC P0563 will set.

Conditions for Running the DTC

System voltage above 16 volts.

Conditions for Setting the DTC

The PCM detects a system voltage above 16 volts for less than 1 second.

Action Taken When the DTC Sets
  1. The PCM will command a message to be displayed.
  2. The PCM will not illuminate the malfunction indicator lamp (MIL).
  3. The PCM will store conditions which were present when the DTC set as Fail Records data only.

Conditions for Clearing the DTC
  1. The PCM will command the message OFF after one trip in which the diagnostic test has been run and passed.
  2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
  3. The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

If the condition is intermittent, refer to Intermittent Conditions in Symptoms.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. If ignition voltage and IPC battery voltage are within 0.5 volt of each other, there may be a system voltage problem. If they are not within 0.5 volt of each other, find out why the PCM is different.

    2.

  2. Tests if the PCM ignition voltage is actually displaying system voltage.

Step

Action

Values

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Start the engine.
  2. Using the scan tool, observe the Ignition 1 voltage display.
  3. Compare the Ignition 1 display to the battery voltage displayed by the IPC message center.

Are PCM and IPC voltage readings different by more than the value specified?

0.5 V

Go to Step 3

Go to Charging System Test in Engine Electrical

3

Using the J 39200 DMM measure voltage to ground on the PCM fuse (installed).

Are the Ignition 1 and DMM voltage readings different by more than the value specified?

0.5 V

Go to Step 4

Go to Charging System Test in Engine Electrical

4

Important: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Is action complete?

--

Go to Step 5

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5
  1. Review and record the scan tool Fail Records data.
  2. Clear the DTCs.
  3. Operate the vehicle with the parameter listed in the Conditions for Running the DTC.
  4. Using the scan tool, observe the Specific DTC Information for DTC P0560 until the test runs.

Does the scan tool indicate that DTC P0560 failed this ignition?

--

Go to Step 2

System OK