I have a 99 Cherokee sport. Originally 2wd. I did a 4x4 swap. Had the tranny rebuilt and then had a transfer case from a 91 (I think a 91) rebuilt and put in. They had to mix and match speed sensors til they had one that fit but had the right wire setup. Ever since then I have had this code. I've read that if you drive under 15 mph the code won't come on. I'm up for an inspection this month. I either have to drive it below 15 mph for 50 miles or come up with another solution I really would like to get this code off. It drives fine and speedometer works correctly. HELP PLEASE!

 

Sounds like the wrong Output Speed Sensor installed or it was wired wrong.


P0720-OUTPUT SHAFT SPEED SENSOR ERROR

When Monitored: Continuously with the vehicle speed over 6 MPH(over the CCD bus) and the transmission is in a forward gear (1st, 2nd , 3rd orOD).

Set Condition: No signal from the Output Speed Sensor for 100seconds.

POSSIBLE CAUSES

INTERMITTENT WIRING AND/OR CONNECTORS
OUTPUT SPEED SENSOR GROUND CIRCUIT OPEN
OUTPUT SPEED SENSOR SIGNAL CIRCUIT OPEN
OSS SIGNAL CIRCUIT SHORTED TO OSS GROUND CIRCUIT
OUTPUT SPEED SENSOR GROUND CIRCUIT SHORT TO GND
OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO GROUND
OUTPUT SPEED SENSOR GROUND CIRCUIT SHORT TO VOLTAGE
OUTPUT SPEED SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
OUTPUT SPEED SENSOR (OUT OF RANGE)
TCM-OUTPUT SPEED SENSOR


This pic shows where the OSS goes.





This pic shows what the OSS looks like.



TEST ACTION APPLICABILITY