For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P0563 : System Voltage High

### Circuit/System Description

The engine control module (ECM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components, and incorrect data may occur when the voltage is out of range.

### Conditions for Running the DTC

• | The vehicle speed is above 25 km/h.

• | Engine running time is greater than 120 seconds.

### Conditions for Setting the DTC

System voltage is greater than 16.58 volts.

### Action Taken When the DTC Sets

• | The ECM will command the charge indicator and or warning message to be illuminated on the instrument panel cluster (IPC) and the driver information center (DIC), if equipped.

• | The malfunction indicator lamp (MIL) will be illuminated after 3 valid driving cycles.

• | The ECM will store conditions, which were present when the DTC set as Fail Records data only.

• | A history DTC is stored.

### Conditions for Clearing the DTC

• | The ECM will command the message OFF after one trip in which the diagnostic test has been run and passed.

• | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | DTCs can be cleared by using the scan tool.

• | Disconnecting the ECM battery feed for 10 seconds

### Diagnostic Aids

If the DTC sets when an accessory is operated, check for a poor connection or excessive current draw.

Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for the following conditions:

• | Backed-out terminals

• | Improper mating

• | Broken locks

• | Improperly formed

• | Damaged terminals

• | Poor terminal-to-wiring connections

• | Physical damage to the wiring harness

### Circuit/System Verification

1. If the DTC is history, refer to Charging System Test .
2. Start the engine. Record the voltage at the battery terminals. Observe the Ignition 1 Signal parameter in the ECM data list. Voltages should not differ by more than 1 volt.

⇒ | If more than 1 volt, replace the ECM.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming