P0662

P0662 sets when the PCM commands the IMRC actuator on bank 1 and the driver circuit reads a voltage HIGHER than expected — typically the driver pulled the line to ground and the line stayed at 12V, indicating an open in the actuator coil, an open in the wiring, or a high-side driver fault inside the PCM. This is the complement of P0661 and uses the same physical hardware; the diagnostic flow shares most of its steps. Cheapest-first ladder: (1) Visual the IMRC connector for backed-out pins or corrosion — diesel and high-mileage gas engines both kill these connectors. (2) Resistance-check the IMRC actuator coil (8-16 ohms cold) — an open coil reads OL on a DMM and is the most common P0662 cause; replace the actuator. (3) Wiggle-test the harness from the actuator back to the PCM with the actuator commanded — intermittent opens at chafe points show up as the code re-setting on motion. (4) If wiring and actuator both check good, the PCM's high-side driver may have failed (rare, but it happens). Target thresholds: actuator coil 8-16 ohms, command line drops to <1V when commanded on, returns to 12V when off, actuator current 0.3-1.5A during sweep. Expensive-misdiagnosis caveat: an open IMRC coil and a broken linkage both throw the same family of codes on some platforms (the PCM can't always distinguish them), and replacing the actuator without checking the linkage means the new actuator stalls against the same jammed butterflies — always free the linkage and confirm full sweep before installing a new actuator.

Vehicle-specific patterns: 2003-2007 Ford 3.0L Duratec (Escape, Tribute, Mariner, Taurus) throws P0662 alongside P0661 when the IMRC actuator coil opens — Ford redesigned the actuator midway through the production run, get the updated part number. 2004-2013 Mazda MZR 2.3L/2.5L (3, 5, 6, CX-7) throws P0662 from the actuator solenoid failing internally; the failure rate climbs sharply past 90k miles. 2010-2017 GM 3.6L LFX/LLT throws P0662 from corroded actuator pins on the front-of-manifold connector or from a failed PCM high-side driver after a poorly grounded jump-start. 2011-2018 Hyundai Theta II 2.4L throws P0662 when carbon buildup increases the mechanical resistance on the IMRC butterflies and the actuator burns out trying to drive against it — fix the carbon, then the actuator. 2007-2014 Subaru Forester/Legacy with the FB25 throws P0662 from the tumble-generator valve (Subaru's IMRC equivalent) failing. Estimated repair: $80 (connector repair) to $750 (full intake manifold + actuator on a GM 3.6).