6L50/6L80/6L90 - Automatic Transmission

DTC P0562 or P0563

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 Low

DTC P0563
- System Voltage High




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. Theses DTC detects high or low TCM voltage for an extended period.


Conditions for Running the DTC


DTC P0562
* Ignition voltage is between 8.6-18.0 volts.
* Engine speed is 1200 RPM or greater.


DTC P0563

Ignition voltage is between 8.6-18.0 volts.


Conditions for Setting the DTC

DTC P0562

The TCM detects system voltage is 11 volts or less for 4 seconds.

DTC 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

Charging System Description and Operation
Scan Tool Reference

Control Module References for scan tool information
DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions


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 .



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.