Buick Regal: DTC P2261

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 P2261

Turbocharger Bypass Valve Stuck

Circuit/System Description

The dual-scroll turbocharger incorporates a wastegate that is controlled by the engine control module (ECM) by means of a pulse width modulation (PWM) solenoid, to regulate the pressure ratio of the compressor. An ECM controlled compressor bypass valve is integrated into the unit to prevent compressor surging and damage from vibrations by opening during abrupt closed throttle conditions.

The bypass valve is open during closed throttle deceleration conditions to allow air to recirculate in the turbocharger and maintain compressor speed.

Conditions for Running the DTC

• DTC P0033, P0034, P0035, P0101, P0102, P0103, P0236, P0237, or P0238 is not set.

  Engine speed is at least 1, 500 rpm

• The boost pressure versus the BARO pressure ratio is between 1.1 - 3.3.
• The turbocharger bypass valve has been commanded Open greater than 6% for greater than 1 s immediately after an abrupt closed throttle has occurred and the resulting pressure ratio across the compressor exceeds the calibrated pressure ratio limit.
• The DTC runs continuously when the above conditions have been met.

Conditions for Setting the DTC

The ECM has detected a series of pulsations in the induction system that exceed a calibrated threshold.

Action Taken When the DTC Sets

DTC P2261 is a Type B DTC.

Conditions for Clearing the MIL/DTC

DTC P2261 is a Type B DTC.

Reference Information

Schematic Reference

Engine Controls Wiring Schematics (LTG)

Connector End View Reference

Component Connector End View Index

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.

2. Verify that DTC P0033, P0034, or P0035 is not set

• If any of the DTCs are set

Refer to DTC P0033-P0035.

• Go to next step: If none of the DTCs are set

3. Verify the scan tool BARO Sensor parameter is within the range specified in the Altitude Versus Barometric Pressure table for the current testing altitude.

• If the parameter is not within the range specified in the table.

Refer to DTC P2227-P2230.

• Go to next step: If the parameter is within the range specified in the table.

4. Verify the scan tool Boost Pressure Sensor and BARO Sensor parameters are within 3 kPa (0.4 psi).

• If the parameters are not within 3 kPa (0.4 psi).

Refer to DTC P0236.

• Go to next step: If the parameters are within 3 kPa (0.4 psi).

5. Verify a click is heard or felt from the Q40 Turbocharger Bypass Solenoid Valve when commanding the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool.

• If a click is not heard or felt

Refer to Circuit/System Testing

• Go to next step: If a click is heard or felt

6. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

7. Verify a DTC does not set.

• If a DTC sets

Refer to Circuit/System Testing

• Go to next step: If a DTC does not set

8. All OK

Circuit/System Testing

NOTE: Leave harness connector connected or re-connect it after removing valve.

1. Ignition Off, remove the Q40 Turbocharger Bypass Solenoid Valve from the turbocharger, ignition On.

2. Verify the turbocharger bypass valve plunger retracts and extends when commanding the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool.

• The valve plunger does not retract and extend

Replace the Q40 Turbocharger Bypass Solenoid Valve

• Go to next step: The valve plunger retracts and extends

3. Verify the conditions listed below do not exist with the turbocharger assembly. Refer to Camshaft Cover and Compressor Air Intake Turbocharger Cleaning and Inspection

• Cracked, damaged or worn turbine blades
• Restricted wastegate, turbine, ports or passages
• Foreign material
• If a condition exists

Repair or replace the turbocharger as necessary

• Go to next step: If none of the conditions exist

4. Replace the Q40 Turbocharger Bypass Solenoid Valve

Component Testing

Static Test

1. Ignition Off, disconnect the harness connector at the Q40 Turbocharger Bypass Solenoid Valve.

2. Test for 10 - 14 Ω between the control terminal 2 and the Ignition terminal 1 of the Q40 Turbocharger Bypass Solenoid Valve.

• If not between 10 - 14 Ω

Replace the Q40 Turbocharger Bypass Solenoid Valve.

• Go to next step: If between 10 - 14 Ω

3. All OK

Dynamic Test

1. Install a 10 A fused jumper wire between the ignition terminal 2 of the Q40 Turbocharger Bypass Solenoid Valve and 12 V. Install a jumper wire between the control terminal 1 and ground.

2. Verify the Q40 Turbocharger Bypass Solenoid Valve plunger retracts.

• If the plunger does not retract.

Replace the Q40 Turbocharger Bypass Solenoid Valve.

• Go to next step: If the plunger retracts.

3. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Turbocharger Bypass Valve Solenoid Replacement

DTC P2618 OR P2619

Diagnostic Instructions

• Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis
• An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions

DTC Descriptor

DTC P2618

Crankshaft Position Signal Output Circuit Low Voltage

DTC P2619

Crankshaft Position Signal Output Circuit High Voltage

Conditions for Running the DTC

• Ignition Voltage=Greater than 11 V
• Ignition=On
• Crankshaft Position Sensor Circuit=Active

Frequency the DTC runs=Continuously - After the running conditions are met

Conditions for Setting the DTC

P2618

Crankshaft Position Signal Output Circuit=Short to Groundor Open - For greater than 5 s

P2619

Crankshaft Position Signal Output Circuit=Short to Voltage - For greater than 5 s

Actions Taken When the DTC Sets

DTCs listed in the DTC Descriptor Category=Type C DTC

Conditions for Clearing the DTC

DTCs listed in the DTC Descriptor Category=Type C DTC

Reference Information

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Circuit/System Verification

1. Engine - Running.

2. Verify there are no DTCs/symptoms related to the following system/component, if equipped:

• K71 Transmission Control Module
• K103 Fuel Injector Control Module
• T3 Audio Amplifier
• T6 Power Inverter Module
• If a DTC or symptom exists

Refer to:

• Diagnostic Trouble Code (DTC) List - Vehicle
• Symptoms - Vehicle
• Go to next step: If no DTC or symptom exists

3. All OK.

READ NEXT: