1985 Isuzu I-Mark 2D Hatchback, AutomaticFACTORY OEM SERVICE PROCEDURE

Open Loop Mode

In this mode, the ECM sends electrical signals to the vacuum control or M/C solenoid based on information stored within the ECM. This information has been calculated and used by the ECM to operate the engine at optimum efficiency for that particular operating condition of the engine, without any input from the sensors. Open loop mode is used when the engine has not reached operating temperature.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.

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.