P226C

P226C-TURBOCHARGER BOOST CONTROL "A" SLOW RESPONSE

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:
With the engine running.

- Set Condition:
The Powertrain Control Module (PCM) detects that the VGT is slow in responding to it's commanded position.





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, repair those DTCs before continuing?

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. Procedures.
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 P226C return?

Yes

- Replace the Turbocharger.
- Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L procedure. Component Tests and General Diagnostics

No

- Repair complete.
- Perform the DIESEL AFTERTREATMENT VALIDATION - 6.7L procedure. Component Tests and General Diagnostics