with all due respect you didnt need a scanner, the WJ reads and displays its own codes with the 3 key trick
with that said, I would use a multimeter and test for continuity on the injector harness.
test things before buying parts to throw at it...
also did you read my previous post?
Did you rent a compression checker?....
2001 WJ Limited NV247 4.7
2008 KK Limited MP253 3.7
2008 WK Limited NV245 3.0 CRD