GM Service Manual Online
For 1990-2009 cars only

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0563 System Voltage High

Conditions for Setting the DTC

    • The system voltage is too high.
    • The transmission control module (TCM) detects that the voltage is greater than 18 volts for 0.5 second continuously.
    • The engine revolution is 600 RPM or greater.

Action Taken When the DTC Sets

The TCM will request the illumination of the malfunction indicator lamp (MIL) and store the DTC when the TCM detects failures on 2 consecutive ignition cycles.

Conditions for Clearing the DTC

    • The TCM turns OFF the MIL when no further failures are detected on the next ignition cycles.
    • The scan tool can clear the DTC from the TCM history.
    • The TCM clears the DTC from the TCM history memory after 40 consecutive ignition cycles without fault.

Cause of Failure

    • The TCM wiring harness and connectors
    • The battery
    • The TCM

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Automatic Transmission?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

  1. Turn OFF the ignition.
  2. Install the scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Run the engine to 600 RPM or greater.
  5. Record then clear the DTCs.
  6. Select system voltage on the scan tool.
  7. Drive the vehicle and observe the scan tool for system voltage.

Is the voltage within the specified range?

9-16 V

Go to Step 5

Go to Step 3

3

  1. Disconnect the battery cable.
  2. Measure the battery voltage.

Is the voltage within the specified range?

9-16 V

Go to Step 5

Go to Step 4

4

Replace the battery.

Did you complete the replacement?

--

System OK

--

5

  1. Turn ON the headlamp.
  2. Turn ON the air conditioner.
  3. Run the engine to 600 RPM or greater.
  4. Observe the scan tool for System Voltage.

Is the voltage within the specified range?

9-16 V

Go to Step 7

Go to Step 6

6

  1. Turn the ignition LOCK.
  2. Repair the alternator circuit, if necessary.

Did you complete the action?

--

System OK

--

7

Test the EF7, F6 fuse for an open.

Was a condition found?

--

Go to Step 8

Go to Step 9

8

  1. Test the EF7, F6 fuse for a short.
  2. Replace the fuse, if necessary.

Did you complete the replacement?

--

System OK

--

9

  1. Turn ON the ignition.
  2. Measure the voltage of EF7, F6.

Is the voltage within the specified range?

9-16 V

Go to Step 11

Go to Step 10

10

Repair the fuse voltage supply lines for open.

Did you complete the repair?

--

System OK

--

11

  1. Turn the ignition LOCK.
  2. Disconnect the transmission control module (TCM) wiring connector.
  3. Measure the resistance between the EF7 fuse and terminal A24 of the TCM wiring connector.

Does the resistance measure the specified value?

0 Ω

Go to Step 13

Go to Step 12

12

Repair the circuit between EF7 and terminal A24 for a short to ground and an open.

Did you complete the repair?

--

System OK

--

13

  1. Disconnect the C204 connector and the TCM connector.
  2. Turn ON the ignition.
  3. Measure the voltage of the terminal A24.

Is the voltage within the specified range?

9-16 V

Go to Step 14

Go to Step 15

14

Repair the circuit from EF7 to terminal A24 of the TCM for a short to battery.

Did you complete the repair?

--

System OK

--

15

  1. Turn the ignition LOCK.
  2. Disconnect the C202 connector.
  3. Measure the resistance between the F6 fuse and terminal A6 of the TCM wiring connector.

Does the resistance measure the specified value?

0 Ω

Go to Step 17

Go to Step 16

16

Repair the circuit between F6 and terminal A6 for a short to ground and an open.

Did you complete the repair?

--

System OK

--

17

  1. Turn ON the ignition.
  2. Measure the voltage of the terminal A6.

Is the voltage within the specified range?

9-16 V

Go to Step 18

Go to Step 19

18

Repair the circuit between F6 and terminal A6 for a short to battery.

Did you complete the repair?

--

System OK

--

19

  1. Inspect the transaxle wiring for poor electrical connectors at the transaxle connector.
  2. Look for possible bent, backed out, deformed, or damaged terminals.
  3. Inspect for weak terminal tension.

Was a condition found?

--

Go to Step 20

--

20

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 21

--

21

  1. After the repair, use a scan tool Clear Info function and road test the vehicle.
  2. Review the DTC info.

Has the last test failed or is the current DTC displayed?

--

Go to Step 2

System OK