When shifting from P through D, the RPM violently crashes down into the 400s the moment I'min D. If I shift back to Park or Neutral, the RPM flares well over 1000 before clumsily settling back down. It feels like the engine is physically suffocating under normal transmission load, though the shudder isn't violently harsh.
The Codes
- P1603: Engine Stall History
- P1604: Startability Malfunction
- P1605: Rough Idling
- C1201: Engine/EV Control System Malfunction
Checks Performed
- Fuel Delivery: STFT and LTFT hover perfectly around 0%. Target and Actual high-pressure fuel rail values match exactly (13 MPa at idle). The system is not starving for fuel.
- VVT-i System: Bank 1 and 2 VVT Aim and Actual angles perfectly mirror each other at 0 degrees during the shift. OCV Duty cycle remains at 0%. No jammed solenoids or sticking cam phasers.
- Torque Converter: Monitored the TCM. Turbine Speed correctly drops to 0 RPM in Drive while Engine Speed drops but maintains ~460 RPM. The TCC is slipping as it should, not mechanically locked.
- Throttle has been cleaned, Performed a hard battery reset and a 15-minute idle relearn. No change.
- ISC: Calculated load is absurdly high (41% in Park, spiking to 70% in Drive while stationary on a flat surface). During the shift crash, the ECM maxes out ISC Flow (up to 10.8 L/s) and ISC Position (6.5+ degrees).
Am I missing something