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 Descriptor

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 voltage circuits. The TCM is located within the control solenoid (w/body and TCM) valve assembly and is not serviced separately. 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 transmission damage.

Conditions for Running the DTC

P0562

The engine is running.

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 10 volts or less for 5 out of 6 seconds.

P0563

The TCM detects system voltage is 18 volts or greater for 5 out of 6 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 battery terminals
       - Loose or corroded connections at the transmission
       - Loose or corroded connections at the accessory power module (APM)

Reference Information

Schematic Reference

    •  Automatic Transmission Controls Schematics
    •  Hybrid Controls Schematics

Connector End View Reference

Component Connector End Views

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 for scan tool information.

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

  1. Ignition OFF, disconnect the X175 transmission 16-way harness connector at the transmission.
  2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuits listed below and ground.
  3. • Terminal 4
    • Terminal 12
         ⇒If the test lamp does not illuminate, test the ignition circuit for a Short to Ground or an Open/High Resistance.
  4. If all circuits test normal, replace the control solenoid (w/body and TCM) valve assembly.
  5. If the voltage is not within the specified value, test the Ignition Voltage circuit for an Open/High Resistance or Short to Ground.
    If the voltage is within the specified range, replace the control solenoid (w/body and TCM) valve assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.