DTC P2261 (LUJ)
Diagnostic Instructions
DTC Descriptor
DTC P2261 00: 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,
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 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 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 optimize 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 modeled airflow that is
derived from these inputs:
Conditions for Running the DTC
• |
DTCs P0033 00, P0034 00, P0035
00, P0097 00, P0098 00, P0100 00, P0101 00, P0102 00, P0103 00,
P0121 00, P0122 00, P0123 00, P0221 00, P0222 00, P0223 00, P0234
00, P0237 00, P0238 00, P0299 00, P2228 00, or P2229 00, are not
set. |
• |
The boost pressure versus the
Barometric Pressure (BARO) ratio is between 1.1-3.3. |
• |
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 compressor exceeds the calibrated pressure ratio
limit. |
• |
The battery voltage is between
10-18 V. |
• |
The engine coolant temperature
is above 39°C (102°F). |
• |
The intake air temperature is
above 4.5°C (40°F). |
• |
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
• |
DTCs P2261 00 is a Type C
DTC. |
• |
The service vehicle soon
indicator will illuminate. |
Conditions for Clearing the DTC
DTCs P2261 00 is a Type C 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
1. |
Verify that DTC P0033 00,
P0034 00, or P0035 00 are not set. |
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. |
3. |
Set up the scan tool for a
snapshot of the induction data list. With the parking 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. |
4. |
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 fluttering sound. There should not be any unusual
noise. |
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. |
Circuit/System Testing
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. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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