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 provide an overview of each diagnostic category.

DTC Descriptors

DTC P0562: System Voltage Low

DTC P0563: System Voltage High

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Short to Voltage

Signal Performance

Ignition 1 Voltage

P2534

P0562

--

P0562, P0563

Accessory Voltage

--

--

--

P0562, P0563

Battery Positive Voltage

--

P0562

--

P0562, P0563

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.

Typical Scan Tool Data

Ignition Voltage

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Operating Conditions: Engine running in PARK, normal operating temperature

Parameter Normal Range: 12.5-14.5 volts

Ignition Voltage

0 volts

0 volts

12.5-14.5 volts

Circuit/System Description

The transmission control module (TCM) continuously monitors the system voltage on the ignition voltage and the battery voltage circuits.

Conditions for Running the DTC

P0562

The engine speed is greater than 1,200 RPM for 5 seconds.

P0563

The ignition is ON.

Conditions for Setting the DTC

P0562

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

P0563

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

Action Taken When the DTC Sets

DTC P0562 and P0563 are type C DTCs.

Conditions for Clearing the DTC

DTC P0562 and P0563 are type C DTCs.

Diagnostic Aids

    • DTC P0562 detects a unacceptable system voltage of less than or equal to 11 volts at the TCM.
    • DTC P0563 detects a unacceptable system voltage of greater than or equal to 18 volts at the TCM.
    • Observe the driver information center (DIC) messaging that would indicate the electrical system requires service.
    • Inspect for loose or damaged terminals at the generator.
    • Inspect for a loose or worn generator drive belt.
    • Use the scan tool in order to inspect all other modules for voltage related DTCs.
    • Running the engine with a battery charger attached may cause DTC P0563 to set.
    • Inspect the charging circuit for high resistance.
    • Inspect the vehicle battery for open or sulfated cells.

Reference Information

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

    •  Component Connector End Views
    •  Inline Harness Connector End Views

Description and Operation Reference

Charging System Description and Operation

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

  1. Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.0 and 15.0 volts.
  2. If the voltage is not within the specified range, refer to Charging System Test.
  3. Ignition ON, engine OFF, accessories OFF, observe the Battery Voltage parameter on the scan tool. The Battery Voltage should be between 12.0 and 14.5 volts.
  4. If the voltage is not within the specified range, refer to Charging System Test.
  5. Engine running, accessories OFF, observe the Ignition Voltage parameter on the scan tool. The Ignition Voltage should be between 12.0 and 14.5 volts.
  6. If the voltage is not within the specified range, refer to Charging System Test.
  7. Increase the engine speed to 1,500 RPM. The Ignition Voltage parameter should remain between 12.0-14.5 volts.
  8. If the voltage is not within the specified range when the engine speed is increased, refer to Charging System Test.
  9. 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

    Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

  1. Engine OFF, disconnect the TCM connector. Connect the negative probe of the DMM to a good ground.
  2. Important: When test probing TCM harness terminals, it is imperative to use the proper test probe from the most current version of the J 35616 GM terminal test kit. Use of the brown J 35616-6 (1.00 mm) PCM probe in a 0.64 mm terminal will deform the terminal, resulting in intermittent open conditions. The correct probe for TCM harnesses is the light blue 0.64 mm J 35616-64B probe.

  3. Ignition ON, engine OFF. Using the light blue 0.64 mm J 35616-64B probe, test for 11.0-14.5 V between the voltage circuit terminals listed below and the good ground.
  4. • Battery positive voltage, TCM connector Terminal 32
    • Ignition 1 voltage, TCM connector Terminal 31
    If 0 V, inspect the Powertrain Control Module ETC fuse, fuse 9, and the Powertrain Control Module Ignition fuse, fuse 14, located in the Underhood Fuse Block, for being open. If open, test the affected circuit for a short to ground.
    If the fuse is not open, test the affected circuit for an open.
  5. Compare the battery positive voltage value to the ignition 1 voltage value from step 3 above. The voltage drop between the circuits should be less than 0.2 volt.
  6. If the voltage drop is greater than 0.2 volt, repair the open or high resistance in the affected circuit.
  7. If all circuits and connections 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