P226B
P226B-TURBOCHARGER BOOST PRESSURE NOT RESPONDING
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Variable Geometry Turbocharger (VGT) 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. Discrepancy 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 after treatment 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.
NOTE: If there are DTCs present with P2262, P226B, P226C, or P2563, address P2262, P226B, P226C, or P2563 before attempting to repair the other fault codes. If however, these DTCs are accompanied by DTC P0471, both DTCs should be addressed and repaired.
1. VEHICLE CONFIGURATION
1. The repair procedure is different depending on whether the vehicle is a Pick Up or Chassis Cab.
Is the vehicle a Pick Up or Chassis Cab?
Pick Up
- Go To 2
Chassis Cab
- Go To 4
2. OTHER DTCs PRESENT
1. Turn ignition on.
2. With the scan tool, read DTCs.
Are there any communication DTCs related to the J1939 Datalink present?
Yes
- Diagnose and repair the communication DTCs before proceeding.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 3
3. TURBOCHARGER CLEANING
NOTE: Do not erase the DTC before attempting to run the VG Turbocharger Cleaning procedure. The procedure can only run if the P2262, P226B, P226C, or P2563 are present (active, pending or stored).
1. Reconnect the Turbo Actuator harness connector.
2. Turn ignition on.
3. With the scan tool, navigate to miscellaneous functions and initialize the VG Turbocharger Cleaning Procedure. Follow the directions on the scan tool completely.
NOTE: When the procedure is initialized you will see one of two messages on the screen.
Which message displayed on the tool?
Turbo does not need to be cleaned;
- The Turbocharger does not need cleaning, or cleaning of the Turbocharger will not fix the stick condition. If DTC P2262, P226B, P226C, or P2563 are active or pending, replace the Turbocharger assembly. If the DTC is stored, erase the DTC. Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L Procedure. Component Tests and General Diagnostics
The engine must idle at 1,500 RPMS for 5 minutes prior to injecting the cleaner;
- The Turbocharger cleaning has initiated. Fasten the cleaning tool to the vehicle and follow the instructions on the screen completely. After the first attempt at cleaning is completed the test will run again automatically and determine if the Turbocharger has been cleaned. The scan tool can make up to three attempts to clean the Turbocharger before failing it. After the cleaning procedure has finished, the scan tool will display the results. If the scan tool displays VG Turbocharger cleaning was successful, the repair is complete. If the scan tool displays VG Turbocharger cleaning was unsuccessful, replace the Turbocharger assembly.
- Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L Procedure. Component Tests and General Diagnostics
4. OTHER DTCs PRESENT
1. Turn ignition on.
2. With the scan tool, read DTCs.
Are there any communication DTCs related to the J1939 Datalink present?
Yes
- Diagnose and repair those DTCs before replacing the Turbocharger assembly.
No
- Replace the Turbocharger assembly.
- Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L Procedure. Component Tests and General Diagnostics