I have two codes coming up po 720 and po 138

P0138 (M) 1/2 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normal operating range. (does this mean I need to replace an o2 sencer??)

P0720 (M) Low Output SPD Sensor RPM, Above 15 mph The relationship between the Output Shaft Speed Sensor and vehicle speed is not within acceptable limits. (bought this truck with a recently overhalled trany and it takes a wile to shift in to second is this why and does any one know what to do about this code??)

This is my first jeep and I realy enjoy it so far its a 96 grand cherokee any help would be much aprechiated. You can email me or pm me.

p_buck420@hotmail.com

Thanks Patrick

 

https://www.cherokeeforum.com/showthread.php?t=3323

This is all I know lol I have renix but it may help a lil or it may just tell you what you already know lol.

 

i would just contact your local jeep dealer and aske the service department what the codes mean.

 

We have the codes listed. Most of further explanation is in the FSM. If you don't have one most libraries have them.