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 Descriptors

DTC P0562: System Voltage High
DTC P0563: System Voltage Low

### Circuit/System Description

The transmission control module (TCM) continuously monitors the system voltage on the Ignition 1 voltage circuits. Lower than normal voltage may be inadequate to operate the transmission control solenoids properly. Improper solenoid operation may cause erratic transmission operation, which may result in internal damage.

### Conditions for Running the DTC

#### P0562

• | Ignition voltage has been greater than 12 volts for 1 second this ignition cycle.

• | Engine speed is 1200 RPM or greater.

#### P0563

Ignition voltage has been greater than 12 volts for 1 second this ignition cycle.

### Conditions for Setting the DTC

#### P0562

The TCM detects system voltage is 11 volts or less for 10 seconds.

#### P0563

The TCM detects system voltage is 18 volts or greater for 10 seconds.

### Action Taken When the DTC Sets

DTCs P0562 and P0563 are Type C DTCs.

### Conditions for Clearing the DTC

DTCs P0562 and P0563 are Type C DTCs.

### Diagnostic Aids

• | Observe the driver information center (DIC) messaging that would indicate the electrical system requires service.

• | Inspect for the following conditions:

- | Loose or damaged terminals at the generator

- | Loose or worn generator drive belt

### Reference Information

#### Schematic Reference

Automatic Transmission Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Scan Tool Reference

• | Scan Tool Output Controls

• | Scan Tool Data List

• | Scan Tool Data Definitions

#### DTC Type Reference

• | Diagnostic Trouble Code (DTC) Type Definitions

• | Diagnostic Trouble Code (DTC) List/Type

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Verification

Engine ON, measure and record the battery voltage with a DMM. The battery voltage should be between 12.5-14.5 volts.

⇒ | If the voltage is not within the specified value, or the charge indicator light is ON, go to Charging System Test.

### Circuit/System Testing

Engine ON, the scan tool Ignition voltage parameter should display between 12.5-14.5 volts.

⇒ | If the voltage is not within the specified value, test the ignition voltage circuit for an open circuit or short to ground.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Perform the Service Fast Learn Adapts.