2012 Acura MDXFACTORY OEM SERVICE PROCEDURE

At high engine speed

The rocker arm oil control solenoid is turned on by the PCM. Oil pressure from the rocker arm control solenoid enters into the intake secondary rocker arm via the rocker shaft, and it moves the VTEC switching piston in the intake secondary rocker arm. This causes the VTEC switching piston to slide into the primary rocker arm, locking the primary and secondary rocker arms together. Both intake rocker arms are lifted by the high lift cam lobe.

Fig 1: VTEC System Operation Diagram (High Engine Speed)
G08052476Courtesy of AMERICAN HONDA MOTOR CO., INC.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.