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 P0244: Turbocharger Wastegate Solenoid Valve Control Performance

DTC P0245: Turbocharger Wastegate Solenoid Valve Control Circuit Low Voltage

DTC P0246: Turbocharger Wastegate Solenoid Valve Control Circuit High Voltage

Diagnostic Fault Information

Circuit

Short to Ground

High Resistance

Open

Short to Voltage

Signal Performance

Ignition 1 Voltage Circuit

P0245

P0244

P0245

--

P0244

Turbocharger Wastegate Solenoid Valve Control Circuit

P0245

P0244

P0245

P0246

P0244

Circuit/System Description

The engine control module (ECM) controls boost using the turbocharger wastegate solenoid valve. The wastegate valve is actuated by a rod from the diaphragm box located at the compressor housing. A spiral spring in the diaphragm box works in the closing direction while the pressure in the diaphragm works in the opening direction. The ECM supplies a PWM signal to a solenoid valve, which then allows pressure from the compressor to come through. When the pressure overcomes the spring force in the diaphragm box, the rod begins to move, opening the wastegate valve to a corresponding degree. The ECM changes wastegate valve opening by varying the PWM signal, which regulates the turbine speed. Ignition voltage is supplied directly to the wastegate solenoid valve. The ECM controls the solenoid valve by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

Conditions for Running the DTCs

DTC P0244

    • TBD
    • TBD
    • This DTC runs continuously within the enabling conditions.

DTC P0245 or P0246

    • The engine speed is greater than 80 RPM.
    • The battery voltage is between 10-18 volts.
    • This DTC runs continuously within the enabling conditions.

Conditions for Setting the DTCs

DTC P0244

TBD

DTC P0245 or P0246

The ECM detects an open, a short to ground, or a short to voltage on the TC wastegate solenoid valve control circuit for greater than 4 seconds continuously, or 50 seconds cumulative.

Action Taken When the DTCs Set

DTCs P0244, P0245, P0246 are Type B DTCs.

Conditions for Clearing the MIL/DTCs

DTCs P0244, P0245, P0246 are Type B DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Turbocharger System Description

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. Ignition ON, command the Turbocharger Wastegate Solenoid Valve to 50 percent with a scan tool. You should hear an audible click.
  2. 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. Inspect the turbocharger and the wastegate solenoid valve for damage. Refer to Turbocharger Cleaning and Inspection
  2. Ignition OFF, disconnect the harness connector at the Q42 turbocharger wastegate solenoid valve.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 2 and ground.
  4. If the test lamp does not illuminate, test the ignition circuit for a short to ground, or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test all components connected to the ignition circuit and replace as necessary.
  5. Connect a test lamp between the control circuit terminal 1 and the ignition circuit terminal 2.
  6. Command the Turbocharger Wastegate Solenoid Valve to 50 percent with a scan tool. The test lamp should illuminate when commanded to 50 percent and turn OFF when commanded to 0 percent.
  7. If the test lamp is always ON, test the control circuit terminal 1 for a short to ground. If the circuit tests normal, replace the K20 ECM.
    If the test lamp is always OFF, test the control circuit terminal 1 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  8. If all circuits test normal, test or replace the Q42 turbocharger wastegate solenoid valve.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turbocharger Disassemble
    •  Control Module References for engine control module replacement, setup, and programming