PRE-RELEASE
DTC P2261
| DTC P2261 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptor |
DTC P2261
Turbocharger Bypass Valve Stuck
| Circuit/System Description |
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 valve , in order to regulate the pressure ratio. A charge air bypass valve is integrated within the unit, and is also controlled by the ECM by utilizing a remotely mounted solenoid valve to prevent surging and damage from vibrations by opening during abrupt closed throttle conditions. When the bypass valve is commanded open during closed throttle deceleration conditions, the bypass valve allows the air to recirculate in the turbocharger and maintain speed. Within a calibrated range during the closed throttle event, or upon a wide open throttle command, the bypass valve will then close to optimize turbocharger response.
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 to a modeled airflow that is derived from these inputs:
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The throttle position
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Engine speed
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Intake Air (Boost) Pressure and Temperature Sensor
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Barometric Pressure (BARO)
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| Conditions for Running the DTC |
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DTC P0101, P0111, P0112, P0113, or P0114 is not set.
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The boost pressure versus BARO ratio is between 1.1-3.2.
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The charge air bypass valve has been commanded ON for greater than 1 s immediately after an abrupt closed throttle has occurred and the resulting pressure ratio across the turbo exceeds the calibrated pressure ratio limit.
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The engine is running.
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The ignition voltage is between 10-18 V.
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The ECM has commanded the bypass valve.
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The intake air temperature is greater than 15°C (59°F).
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The DTCs run continuously when the above conditions are met.
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| Conditions for Setting the DTC |
The ECM detects that the bypass valve is stuck in the closed position. 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 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
Turbocharger System Description
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
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Ignition ON, check the diagnostic trouble code (DTC) information with a scan tool. DTCs P0033, P0034 or P0035 should not set.
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If any of the DTCs are set, refer to
DTC P0033-P0035
for further diagnosis.
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Ignition ON, command the Turbocharger Bypass Solenoid Valve between Inactive and Active with a scan tool. An audible click should be heard.
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Engine running, command the Turbocharger Bypass Solenoid Valve between Inactive and Active with a scan tool while observing the following control circuit status parameters:
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Turbocharger Bypass Solenoid Valve Control Circuit High Voltage Test Status
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Turbocharger Bypass Solenoid Valve Control Circuit Open Test Status
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Turbocharger Bypass Solenoid Valve Control Circuit Low Voltage Test Status
The parameters should alternate between OK and Not Run with each change in command. |
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Engine idling, rapidly depress the accelerator pedal from the rest position to the wide open throttle (WOT) position and release pedal. A valve that is stuck shut will generate an unusual pulsating noise. Compare to similar vehicle. There should not be any unusual noise.
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If there is unusual noise, refer to
Turbocharger Cleaning and Inspection
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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.
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| Circuit/System Testing |
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Inspect for any damage, restrictions, improper routing or connecting of the vacuum hoses on the charge air bypass solenoid valve and the charge air bypass valve.
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If a condition is found, repair as necessary.
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Clear the DTC and operate the vehicle within the Conditions for Running the DTC.
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If the DTC cannot be cleared or continues to reset, replace the charge air bypass valve.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Turbocharger Disassemble
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Control Module References
for ECM replacement, setup, and programming
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