Gear 4 Incorrect Ratio, what steps do I need to take in finding the problem repair. I would rather not start with replacing the transmission computer.

 

How many times has it come up?
Sometimes it comes up as a fluke.

 

Only once for me, the tranny was winding out and wouldn't shift. Got the flashing arrow, engine light on the dash. Arrow reset after a day. Has happened to my daughter before as well as a solid arrow. Many, many problems with this car once it got over 150k miles. I have a ghost electrical problem currently that will cut off the car at low RPMs, sometimes the radio code has to be reset. Always starts back up. Replaced battery/checked cables, checked/tightened all the grounds, replaced alternator, had computer flashed. One last suggestion was to replace the ignition switch. Spent way too much, car has 170k miles on it.

 

I would reset the code and see how long it takes to come back.