What is the correct gear for automatic and manual transmissions during an ASM test?

• A. Automatic in Park, Manual in Neutral.
• B. Automatic in Drive, Manual in 3rd gear.
• C. Automatic in Drive, Manual in 2nd gear.
• D. Automatic in Reverse, Manual in 4th gear.

Answer: (D)

During an ASM test you want the engine under a real load, not idling with the drivetrain disengaged. Putting the automatic in Reverse provides the necessary load at low speed without moving the car, while a manual transmission in fourth gear gives a higher gear ratio that keeps engine RPM in the test range while maintaining that load. Using Park or Neutral removes drivetrain load and can skew readings, and other gear choices won’t consistently place the engine in the proper load/ RPM window for the test. So the setup where the automatic is in Reverse and the manual is in fourth gear aligns with maintaining an appropriate engine load during the ASM test.