Cruze

DTC P2261

The turbocharger incorporates a wastegate that is controlled by a pressure differential, that is determined by the engine control module (ECM) by means of a pulse width modulation (PWM) solenoid, in order to regulate the pressure ratio of the compressor. A charge air bypass valve is integrated within the module, and is also controlled by the ECM by utilising 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 turbocharger 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 optimise turbocharger 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 modelled airflow that is derived from these inputs:

The ECM by comparing the measured MAF to the modelled MAF has detected a series of pulsations in the induction system that exceed a calibrated threshold.

DTCs P2261 00 is a Type C DTC.

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

1. Verify that DTC P0033 00, P0034 00, or P0035 00 are not set.

⇒	If any of the DTCs are set, refer to DTC P0033-P0035 .

2. Use the scan tool output controls to command the Turbocharger Bypass Solenoid to 100% and down to 0%. An audible click should be heard and felt.

⇒	If the click is not heard or felt, refer to DTC P0033-P0035 .

3. Set up the scan tool for a snapshot of the induction data list. With the handbrake 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 handbrake 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 fluttering sound. There should not be any unusual noise.

⇒	If there is unusual noise, refer to Turbocharger Cleaning and Inspection .

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.

1. Inspect for any vacuum leaks, damage, restrictions, improper routing or connecting of the vacuum hoses on the Q40 Turbocharger Bypass Solenoid Valve solenoid and the charge air bypass valve vacuum tank.
2. 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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for ECM replacement, setup, and programming