2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1866
Component Testing
1. Ignition OFF, disconnect the KR25 secondary air injection pump relay.
2. Test for 70-110 ohm between terminals 85 and 86.
瀚慖f the resistance is not within the specified range, replace the KR25 secondary air injection pump relay.
3. Test for infinite resistance between the following terminals:
* 86 and 87
* 86 and 30
* 85 and 87
* 87 and 30
瀚慖f not the specified value, replace the KR25 secondary air injection pump relay.
4. Install a 20 A fused jumper wire between relay terminal 86 and B+. Install a jumper wire between relay terminal 85 and ground. Test for less
than 2 ohm between terminals 87 and 30.
瀚慖f greater than the specified range, replace the KR25 secondary air injection pump relay.
Repair Instructions
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
