2010 Cadillac Truck SRX FWD V6-3.0L Page 2026

2010 Cadillac Truck SRX FWD V6-3.0L Page 2026

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

Control Module References (See: Testing and Inspection/Programming and Relearning)for engine control module replacement, setup, and

programming

P2261

DTC P2261

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.

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:

* The throttle position

* The engine speed

* Intake Air (Boost) Pressure and Temperature Sensor

* Barometric Pressure (BARO)

Conditions for Running the DTC

* DTC P0101, P0111, P0112, P0113, or P0114 is not set.

* The boost pressure versus BARO ratio is between 1.1-3.2.

* 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.

* The engine is running.

* The ignition voltage is between 10-18 V.

* The ECM has commanded the bypass valve.

* The intake air temperature is greater than 15掳C (59掳F).

* The DTCs run continuously when the above conditions are met.

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.