Output speed sensor problems P0720
check engine light is on showing code for the output speed sensor. I changed the output speed sensor, check engine light still on and occasionally the over drive light flashes. Any suggestions?
thanks
Mike

 

Fix the problem with the wiring harness between the PCM and the OSS.

 

like Mark said, this is what I did there's three senors disconect all three pull down the wire harness and check the wires mine was corroded about two inches from the connector in the conduit. while you have the harness down check all the others. also check your Grounds are all clean and making good contacts.

 

If I disconnect the wiring harness from the output sensor, and check it electrically how many volts should I have?

 

You should have zero volts if the circuit is good. If it's bad, you'll still have zero volts. That isn't how you check it. Check from the PCM to the sensor connector for continuity, short to power, and short to ground. Checking for voltage won't tell you anything.

 

Thank you, ill be checking the wiring in the next few days

 

just another thought< check the wire that goes to the overdrive button that wire sometimes breaks. its under the plastic cover in the steering column that might also giver you that code intermittently.

 

How in the world could that wire give you that code? That's quite a stretch.

 

Had truck to shop, they believe I have a weak coil, so far I've changed 4 coils, no luck so far, does it seem realistic that I have a weak coil that would not show a code for a coil but the output sensor code 0720?
thanks
Mike

 

No, it's not realistic.

-- Dave

 

Problem solved, bad electric connection as you have said. Thank you

 

My 1999 ford expeditions' speedometer is fluctuating when I climb the mountain to go to town. Either way there's a mountain, so it has to be driven across to get to.
Flat land its fine but climbing ids when it fluctuates and the transmission also downshifts when it fluctuates like that. what could be the problem?

 

There are a bunch of things that could be the problem. You should start your own thread about it if you want to fix it. This thread talks about a code for the output speed sensor. Is that what you have?

 

Hey guys my name is Mike, I see that you have a lot of knowledge with these issues. I have a few questions about my 2004 f250 SD XLT 5.4L. So I replaced my trans range sensor and I still sometimes get the P0705 code. I was also getting a P0720 output speed sensor code, so I replaced that as well and I still get that code sometimes, but that isn't all. A few months ago the truck just started stalling when in gear/ low idle, running rough and throwing P0171 too lean bank 1 and P0174 too lean bank 2 codes. I smoke tested and found 2 evap leaks that I fixed. Truck ran well for 10-15 mins and started stalling in gear/ idle and occasionally power loss again. Then hen someone said it could be the fuel pump relay or fuel pump but I did a new fuel pump a little over a yr ago and a new fuel filter 3 days ago. So then I replaced the fuse box bc fuel relay is built in, truck ran beautiful for 10-15 mins then started stalling in gear and low idle/ occasionally power loss again and im getting P0720 and P0171 codes now. Im so confused and frustrated, any idea what my problem is? Could all these things be related, maybe a wiring issue? I keep thinking I fix it and i haven't yet and I'm ready to drive it off a cliff. Anything you could think of would be GREATLY APPRECIATED! Thank you. -Mike

 

Having the P0720 codes does not mean you should change the output speed sensor. It means you should diagnose what's wrong. Most of the time the problem is in the wiring to the sensor, not the sensor itself.