Toyota and Lexus Firmware 89663-28420-A

89663-28420-A is a Toyota or Lexus calibration identifier associated with the related catalog entry 89663-28420. The 89663 part-number family is associated with engine control software, so an engine control module application is a tentative match.

Engine control software generally manages functions such as fuel delivery and ignition timing to support engine operation and emissions control. The identifier alone does not establish the vehicle application, the specific function of this calibration, or a change made by this revision.