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 P0560: System Voltage

Circuit/System Description

The powertrain control module (PCM) monitors the system voltage to ensure that the voltage stays within the proper range. Damage to components and incorrect data may occur when the voltage is out of range.

Conditions for Running the DTC

    • The vehicle speed is below 40 km/h(25 mph).
    • The system voltage is below 11 volts or above 16 volts.
    • Engine speed is above 1,500 RPM.

Conditions for Setting the DTC

The PCM detects a system voltage out of range for 2 seconds.

Action Taken When the DTC Sets

DTC P0560 is a C type DTC.

Conditions for Clearing the DTC

DTC P0560 is a C type DTC.

Diagnostic Aids

    • A high or low voltage DTC set in multiple modules indicates a concern in the charging system.
    • A possible cause of this DTC could be overcharging with a battery charger or jump starting.
    • A high or low voltage value in multiple modules indicates a concern in the charging system.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

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. Verify DTC P0560 is set as current.
  2. Engine running, accessories OFF, measure and record the voltage at the battery terminals.
  3. The voltage should be between 12.6 and 15.5  volts.
  4. If battery voltage not within the specified range, refer to Charging System Test
  5. Engine running, observe the scan tool PCM Ignition  1 signal parameter.
  6. Verify that the scan tool displays a value that is within 2 volts of the battery terminal voltage.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connectors at the PCM.
  2. Ignition OFF, verify that there is less than 3.0 ohms between the ground circuit X2 terminal 73 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify a test lamp illuminates between the Ignition  1 circuit X1 terminal 19 and ground.
  5. If the test lamp did not illuminate , test the Ignition  1 circuit for a short to ground or an open/high resistance.
  6. If all circuits test normal, replace the PCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for PCM replacement, setup, and programming