Diagnostic Instructions
DTC Descriptor
DTC P2261: Turbocharger Bypass Valve Stuck Closed
System Description
The BorgWarner™ dual-scroll turbocharger (TC) incorporates a wastegate that is controlled by a pressure differential, that is determined by the engine control module (ECM) by means of a PWM solenoid, in order to regulate the pressure ratio of the
compressor. A charge air bypass valve is integrated within the unit, and is also controlled by the ECM by utilizing a remotely mounted solenoid to prevent compressor surging and damage from vibrations by opening during abrupt closed throttle conditions. When
the valve is commanded open during closed throttle deceleration conditions, the bypass valve allows the air to recirculate in the TC and maintain compressor speed. Within a calibrated range during the closed throttle event, or upon a wide open throttle command,
the valve will then close to optimize TC response.
Front wheel drive platforms also incorporate a charge air 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.
The purpose of this diagnostic is to determine if the charge air bypass valve is stuck closed. The ECM will first verify the integrity of the following sensors. The ECM then compares the actual measured mass air flow (MAF) to a modeled airflow that is
derived from these inputs:
• | Intake air pressure sensor |
• | Manifold absolute pressure (MAP) sensor |
Conditions for Running the DTC
• | DTCs P0033, P0034, P0035, P0096, P0097, P0098, P0099, P0100, P0101, P0102, P0103, P0106, P0107, P0108, P0121, P0122, P0123, P0221, P0222, P0223, P0234, P0236, P0237, P0238, P0299, P2227, P2228, or P2229, is not set. |
• | The boost pressure versus the BARO pressure ratio is between 1.1-3.3. |
• | The charge air bypass valve has been commanded ON for greater than 1 second immediately after an abrupt closed throttle has occurred and the resulting pressure ratio across the compressor exceeds the calibrated pressure ratio limit. |
• | The battery voltage is between 10-18 volts. |
• | This DTC runs continuously within the enabling conditions. |
Conditions for Setting the DTC
The ECM by comparing the measured MAF to the modeled MAF 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 Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
- Verify that DTC P0033, P0034, or P0035 is not set.
- Use the scan tool output controls to command the TC Bypass Solenoid ON and OFF. An audible click should be heard and felt.
- 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.
- 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 turkey gobble
sound. There should not be any unusual noise.
- 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
- Inspect for any vacuum leaks, damage, restrictions, improper routing or connecting of the vacuum hoses on the charge air bypass valve solenoid, the charge air bypass valve, and the charge air bypass valve vacuum tank.
- Clear the DTC and operate the vehicle within the Conditions for Running the DTC.
⇒ | If the DTC cannot be cleared or continues to reset, then replace the charge air bypass valve. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.