What in the world is a code 55. I did a test on my 91 cherokee with the key on-off 3 times and it reads 12 then 55. any thoughts. I have a no spark issue read on here that if I have no spark to pull a plug after cranking it to look for wetness of gas and nothing. So I'm thinking it's the CPS. any thought guy's thanks in advanced

 

code 12 is (memory to controller has been cleared within 50-100 engine starts) and code 55 is (end of message)
these codes are from a chiltons book

 

I looked in my book but only found the 98 and later codes. guess these codes are of no help to me.

 

these are for 91-95. the codes that start with a "p" are for 96 and newer

 

Correct. Both are not codes indicating any problem.

The #1 cause of no spark in the 4.0 is the crankshaft position sensor. Test it.

The #2 cause is the ignition coil. Again, test it.

The #3 cause is a problem with the ASD circuit (try swapping ASD relay with another here first)

The #4 cause can be the ignition switch itself

But as the crank sensor is the most common sensor fail on the 4.0, I would start there.

Most of the time, a bad crank sensor will NOT set a check engine light or code!

 

Thank you everyone, replaced the ignition coil, how do I test the Cps?