Honda StepWGN: Sport Hybrid i-MMD Low-Speed Shudder and EV-to-Engine Transition Jolt

The Step WGN Spada Hybrid uses Honda's Sport Hybrid i-MMD (Intelligent Multi-Mode Drive) two-motor system, which couples a 2.0L Atkinson-cycle engine with front and rear electric motors through a single fixed-ratio drive gear and a wet clutch. The transition from pure EV propulsion into engine-assist mode under light acceleration produces a characteristic shudder or lurch, caused by timing tolerances in wet-clutch engagement and torque handover between the motor and combustion engine; the symptom worsens as the clutch friction material wears and when the high-voltage battery state-of-charge is low. Honda issued software calibration updates in Japan to reduce symptom severity, but units that have accumulated urban stop-start mileage above 80,000 km often require clutch pack inspection or replacement.

• Shudder or vibration felt through floor and seat when pulling away from rest at light throttle
• Momentary hesitation or lurch when the combustion engine engages during gentle acceleration below 40 km/h
• HV system or IMA warning lamp illuminated on instrument cluster
• Fuel consumption higher than specification due to engine cutting in prematurely

1. 1

   Test drive in urban conditions with frequent stops; note any lurch or vibration when accelerating from 0-20 km/h after a full stop.

2. 2

   Check for DTCs P17F0, P17F1 or HV system warning lights.

3. 3

   Inspect high-voltage battery state of health via Honda diagnostic interface.

4. 4

   Verify software version matches latest Honda Japan service bulletin calibration.

Parts involved: Clutch.

$400 to $5,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the hybrid transmission software been updated to the latest Honda Japan calibration?”
• “Has the wet clutch pack ever been inspected or replaced?”
• “What is the current high-voltage battery state of health as measured by a Honda dealer scan tool?”
• “Does the vehicle shudder or lurch when pulling away gently in EV mode?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.