P2261

DTC P2261

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P2261
- Turbocharger Bypass Valve Stuck

System Description

The BorgWarner(TM) 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, which uses a remotely mounted solenoid, 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. The valve closes during open throttle commands, to optimize turbo response.

Front wheel drive platforms also incorporate a bypass valve vacuum tank. The purpose of the tank is to provide an instant source of vacuum to the bypass valve, when it is commanded open by the ECM. This results in less pressure buildup under closed throttle conditions, thereby reducing compressor noise and surge.

Conditions for Running the DTC

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

* 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.

Diagnostic Aids

The turbocharger bypass valve vacuum tank contains an internal check valve to prevent the tank from being pressurized during boost conditions. A leaking check valve will result in insufficient vacuum to open the turbocharger bypass valve after a quick throttle closing, causing abnormal pulsations and unusual noise.

Reference Information

Schematic Reference

Engine Controls Schematics [1][2]Electrical Diagrams

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

Turbocharger System Description Description and Operation

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information.

Special Tools

J-23738-A - Mityvac

Circuit/System Verification

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

• If a DTC is set, refer to DTC P0033-P0035 P0033 for further diagnosis.

2. Engine running, command the Turbocharger Bypass Solenoid Valve between Active and Inactive with a scan tool. A click should be heard and felt.

3. Set up the scan tool for a snapshot of the induction data list. With the emergency brake on, the vehicle transmission in neutral, and the engine idling, perform a wide open throttle and then quickly release the accelerator. Review the Boost Pressure Sensor parameter. There should not be any abnormal pulsations of the parameter.

4. With the parking brake ON and the engine idling in neutral, perform an audible test of the valve by depressing the throttle wide open, then quickly releasing it to a closed throttle position. A valve that is stuck shut will generate a rapid pulsating or fluttering sound. There should not be any unusual noise.

5. 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. Verify the conditions listed below do not exist:

* Vacuum leaks

* Vacuum line restrictions

* Improper routing or connecting of the vacuum hoses on the turbocharger bypass valve solenoid, the bypass valve, and the bypass valve vacuum tank

• If a condition is found, repair or replace the affected component as necessary.

2. Ignition OFF, disconnect the vacuum supply hose from the Q40 turbocharger bypass solenoid valve and connect the J-23738-A or a suitable vacuum gauge to the hose.

Note:

* Engine temperature, accessory load, and elevation level will affect engine vacuum.

* Vacuum readings will decrease by approximately 2.7 kPa (0.8 in Hg) for every 305 m (1,000 ft) of elevation above sea level.

3. Engine Idling, the gauge should read between 47-68 kPa (14-20 in Hg).

• If not within the specified range, inspect and repair the vacuum source or the vacuum leak in the areas listed below:

* The vacuum hose between the Q40 turbocharger bypass solenoid valve and the turbocharger bypass valve vacuum tank

* The turbocharger bypass valve vacuum tank

* The vacuum hose between the turbocharger bypass valve vacuum tank and the intake manifold

4. Ignition OFF, disconnect the J-23738-A or vacuum gauge and reconnect the hose to the Q40 turbocharger bypass solenoid valve

5. Disconnect the vacuum hose from the turbocharger bypass valve and connect the J-23738-A or a suitable vacuum gauge to the hose.

6. Engine Idling, command the turbocharger bypass solenoid valve between Active and Inactive with a scan tool while observing the vacuum gauge. The gauge should read between 47-68 kPa (14-20 in Hg) when commanded Active and 0 kPa (0 in Hg) when commanded Inactive.

• If not within the specified range, inspect the vacuum hose for a leak or restriction. If a condition is found, replace the hose. If a condition is not found, replace the Q40 turbocharger bypass solenoid valve.

7. Ignition OFF, inspect the turbocharger bypass valve assembly for damage. Refer to Turbocharger Cleaning and Inspection (LDK, LHU) Turbocharger Cleaning and Inspection.

8. Disconnect the vacuum hose that runs from the turbocharger bypass valve vacuum tank to the Q40 turbocharger bypass solenoid valve at the tank.

9. Connect the J-23738-A to the turbocharger bypass valve vacuum tank.

10. Apply 51 kPa (15 inches Hg) of vacuum to the tank. Verify the tank maintains vacuum without decay.

• If the tank does not maintain vacuum, replace the turbocharger bypass valve vacuum tank.

11. If all components test normal, replace the charge air bypass valve.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Charge Air Bypass Valve Replacement Charge Air Bypass Valve Replacement

* Charge Air Bypass Valve Vacuum Tank Replacement Charge Air Bypass Valve Vacuum Tank Replacement

* Turbocharger Control Solenoid Valve Replacement Turbocharger Control Solenoid Valve Replacement for turbocharger bypass valve solenoid replacement.