P226C - Turbocharger Boost Control 'A' Slow Response
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Turbocharger Boost Control 'A' Slow Response (P226C).
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Turbocharger Boost Control 'A' Slow Response – Coil Resistance | Resistance (Ω) | 3 - 30 Ω (typical) | Connector disconnected at 20°C |
| Turbocharger Boost Control 'A' Slow Response – Duty Cycle | PWM (%) | 5 - 95 % (modulates with target) | Engine running, actuator in control |
| Turbocharger Boost Control 'A' Slow Response – Supply Voltage | Voltage (V) | 11.8 - 14.4 V | Ignition ON at connector |
Connector disconnected at 20°C
Engine running, actuator in control
Ignition ON at connector
Oscilloscope Waveform Analysis
2 ms/div, 20 V/divPossible Causes
Channel A:Verify dedicated wiring pins and signal pair for circuit A against the schematic.
Chafed or pinched wiring harness along the signal path to Turbocharger Boost Control 'A' Slow Response
Internal mechanical wear or carbon deposits inside Turbocharger Boost Control 'A' Slow Response
Defective internal output driver or reference circuit in the control module for Turbocharger Boost Control 'A' Slow Response
Symptoms
Recommended Solution
Compare signal voltage and resistance between circuit A and companion circuit B at module connector.
Review freeze-frame environmental data and perform fundamental voltage-drop and resistance checks on the circuit.
Verify loaded supply voltage and harness terminal pins at Turbocharger Boost Control 'A' Slow Response.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Turbocharger Boost Control 'A' Slow Response.
Check supply and the low-side driver at the ECM connector. Replace the actuator or repair the circuit based on the readings.
Mechanic's Tip
Use the scan-tool output test with the scope on the control side at the same time. If duty changes but the actuator does not move, the valve is stuck — not the electrical fault you were chasing.