GM Service Manual Online
For 1990-2009 cars only

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) within the control solenoid, w/body and TCM, valve assembly continuously monitors the system voltage on the ignition voltage circuit.

Conditions for Running the DTC

Input Speed is 800 RPM or greater.

Conditions for Setting the DTC

P0562

The TCM detects that battery voltage is less than 9.0 volts for 1 second.

P0563

The TCM detects that battery voltage is greater than 18.0 volts for 1 second.

Action Taken When the DTC Sets

    • DTC P0562 and P0563 are Type A DTCs.
    • The TCM inhibits Adaptive Control.
    • The transmission will operate in 4th gear in D range, Reverse in R range.

Conditions for Clearing the DTC

DTC P0562 and P0563 are Type A DTCs.

Diagnostic Aids

A charging system malfunction may cause variances in system voltage and set voltage related DTCs.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Transmission General Information

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References

Circuit/System Verification

  1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 9.0-18.0 volts.
  2. If not within the specified range, refer to Charging System Test .
  3. Observe the scan tool TCM Battery Voltage parameter. The reading should be between 9.0-18.0 volts.
  4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the transmission control module (TCM).
  2. Test for less than 1.0 ohm of resistance between ground circuit terminal 40 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 41 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the TCM.
  6. If all circuits test normal, replace the TCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for TCM replacement, setup, and programming