P226B
P226B-TURBOCHARGER BOOST PRESSURE NOT RESPONDING
For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation
The VGT (Variable Geometry Turbocharger) adjusts turbocharger performance by moving the position of the impeller nozzle, on the high-pressure (engine exhaust gas) side of the turbocharger assembly. Desired position of the actuator is commanded from the Powertrain Control Module (PCM). Actual position is sensed by the VGT, and reported back to the PCM as feedback. Discrepency in position feedback sent to the module, and commanded position sent to the VGT by more than a prescribed amount will result in failure of device rationality diagnostics. Failure to properly actuate the VGT will result in poor engine performance. The PCM lights the MIL lamp after the diagnostic runs and fails in two drive cycles. The PCM will turn off the MIL lamp immediately after this diagnostic runs and passes in four consecutive drive cycles.
- When Monitored:
When the engine is in regeneration of the aftertreatment system.
- Set Condition:
Turbo position is not within the commanded position during desoot or the difference between charge flow and charge flow command is over the calibrated limit.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. OTHER DTCS
1. Turn ignition on.
2. With the scan tool, read DTCs.
Are there any EGR Airflow Control Valve, Mass Air Flow Sensor, or Intake System leak related DTCs present?
Yes
- Repair those DTCs before proceeding.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 2
2. TURBOCHARGER CLEANING
1. Perform the Turbocharger cleaning procedure. Turbocharger - Cleaning.
2. With the scan tool, erase DTCs.
3. Turn the ignition off for 75 seconds.
4. Start the engine and test drive the vehicle.
5. With the scan tool. read DTCs.
Did DTC P2262 set as active or pending?
Yes
- Perform the P2262 diagnostic procedure. P2262.
No
- Repair complete.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.