Automatic Transmission (6L50/6L80/6L90)

DTC P0562 or P0563

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.

DTC Descriptor
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 11.0 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 indicates 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 (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics).
* Connector Repairs (Component Tests and General Diagnostics).
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics).
* Wiring Repairs (Component Tests and General Diagnostics).

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information
DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)

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, refer to Charging System Test (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

Important: Always perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.


Perform the Service Fast Learn Adapts (Programming and Relearning).