Engine Identification Number Locations: 4.0L
For both the Grand Cherokee and Wrangler, the engine build date code is located on a machined surface on the right side of the cylinder block. See Fig 1 . The digits of the code identify the following.
- 1st digit identifies the year (3 = 2003).
- 2nd and 3rd digits identify the month. Example; (01 - 12).
- 4th and 5th digits identify the engine type/fuel system/compression ratio. HX = 2.5L (150 CID) 9.1:1 compression ratio engine with a multipoint fuel injection system. MX = 4.0L (242 CID) engine with multipoint fuel injection system.
- 6th and 7th digits identify the day of engine build. Example; (01 - 31).