U02AFLost Communication With Turbocharger Turbine Inlet Valve Position Sensor
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- In staged turbocharging a valve in the exhaust path decides how much gas passes through the small high-pressure stage and how much goes around it. GM's patent keeps this valve closed in one load and speed region, modulates it in a transition region and coordinates it with the variable vanes; Ford's two-stage patent opens the bypass fully and cuts torque when valve control is lost. Both depend on knowing the actual valve position. U02AF concerns a position sensor that sends that value digitally, for example as SENT frames, and has stopped doing so. No manufacturer documents U02AF publicly. An analog sensor would report P22D4 to P22D8 instead. CARB expects lost communication of digital inputs to set its own code. The engine typically limits boost and lights the MIL.
- What you may notice
- Check engine lamp
- Boost limited, sluggish response at low and medium engine speed
- Engine in reduced-power mode
- Likely causes
- LikelyHeat-damaged connector or wiring at the sensor near the exhaust
- PossiblePosition sensor electronics failed
- PossibleSensor supply or ground missing
- RareFault at the engine controller input
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.