Hey everybody I need help. My 1999 xj is showing a no engine bus code everything is running great no blown fuses gauge cluster works but the "wonderful"state of California requires me to turn that stupid little CEL off for a smog tech to even look at it I'm at a loss suggestions are welcome I just need help just bought this jeep so I need to fix soon thanks for reading

 

I forgot to mention this jeep is a non abs automatic with part time and full time 4wd and the part time light will not turn off when disengaged from 4wd if that helps at all

 

Remove and clean grounds G100 and G101. G100 is next to the battery to the fender. G101 is just below the ignition coil. Sometimes that will fix a "NO BUS". If not, the gauge cluster itself may have a loose or dirty connection.

 

Check your 5v line connections with a multimeter. If no 5v line is present there is a short somewhere. The sensors that use the 5v lines are:

TPS
​​​Cranksensor
cam sensor
MAP sensor
Vehicle Speed Sensor
Oil pressure sensor
(Think I'm forgetting one)

prope the TPS with the multimeter and start removing sensors in hopes the 5v comes back. If you remove a sensor and your 5v does come back, you have found the short.

Had this problem recently, no bus no start. Ended up being a short at the oil pressure sensor harness.

If none of these sensors bring the 5v back, youre gonna need some wiring diagrams to test for shorts elsewhere along the + power line.

 

In case you start to get low on things to check:

https://www.cherokeeforum.com/f2/cod...166340/index5/