Howdy, I have a 1998 Dodge ram 1500 v8 5.2 L
I am getting a code of P0720 on the new handy dandie OBD2 code reader I bought. It says its a low speed sensor failure. The stuff in the p07XX range looks like transmission problems. But the thing is, the engine bogs when I stomp on the gas till I get to about 20 mph then it runs great again. The fuel efficiency seems to be down by about15% as well. Are these things related? They seem to be in sepperate areas, I really dont notice any problems with the tranny, but the bog is very noticeable. Any tips appreciated, TIA!

 

<FONT face=Arial size=2>Low Output speed sensor rpm above 15 mph.

The relationship between the output shaft speed sensor and vehicle speed is not within acceptable limits.

Did one of the speed sensor plugs become loose on the side of your trans? </FONT>

 

Well this one falls under the duhh category. The probe on the output of the tranny was good, even the probe continuity checked ok. The probe tip simply had some ferrous fuzz on it. The metal fuzz on the end was essentially preventing the target gear teeth from being read. The end of the probe is magnetic so it was covered uniformly. Since this probe works by detecting a metal tooth passing in front of it, it was hampered by being covered in ferrous material-it would see it as a much degraded signal, if any at all.

Cleaned the tip, reinserted and the bogg on the low end went away, check engine light stayed off at speeds greater than 20 mph. Problem solved looks like. One other thing was that I had not done a tranny flush on this truck yet-its just coming up on 100K too. The check engine light spurred me in to doing all the tuneup maintenance, when that didnt help I bought a OBD2 reader and it pointed out the tranny problem. It was $100, but what a huge savings compared to bringing it in to get it fixed.

I hope this can help someone out in the future.