I just went to get emissions done and it failed the guy said that the P0720 - Output Speed Sensor Circuit Malfunction. And that the MIL status fail in regards to Bulb Check, Mil Command, OBD readiness. That when the car starts the MIL light is supposed to come on then go out, but none of that is occurring he said with it like that I wouldn't be able to tell if the check engine light was on or off.

i forgot to ask has anyone encountered this or know a fix?

 

[:@]...........well that sucks

 

It might just be a bulb in the dash. The CEL should come on when you turn the key on and then turn off shortly after you start the car. Are you running MIL eliminators? Or is it turned off in your tune? I have heard of people having problems getting to pass the OBDII readiness test if its turned off in the tune.

 

Maybe someone pulled the old "take out the check engine light and its all good" trick

 

No I have hi flow cats, and no MIL Eliminators, i don't think I have a chip but im not really sure the car was bought completely hooked up. now if a bulb is out on the dash do or should I attempt to pull the cluster out?

 

I found this on line so I guess i'll try switching out the sensor on my tranny and see if thats the fix. P0720 - Insufficient input from Output Shaft Speed sensor The output shaft speed sensor inputs a signal to the PCM, based on the speed of the output shaft of the transmission. The PCM compares this signal with the signal of the VSS or TCSS and determines correct tire size and axle gear ratio. OSS sensor circuit short to GND
OSS sensor circuit short to PWR
OSS sensor circuit open
Damaged OSS sensor
Damaged PCM
Verify sensor signal output varies with vehicle speed.

 

Well if the light doesn't come on at all when you turn the key to the on position then yeah the light is probably out. Also if you don't have mil eliminators or turned off the 02's with a tuner you will fail. As far as the other thing though I can't help you with that. sorry

 

wait...

so your saying that if I have my o2 sensors turned off (with my tune), I will not pass my OBII tests? Even if the light works? and even if I also have MIL Eliminators? (redundant but got them before the tune)

 

sorry bad choice of wording

you will fail if.....
1. you don't have mil eliminators
2. you haven't turned off your rear o2 sensors

 

I'm curious... Where do you live? I'm a Licensed emissions inspector, and these checks are very different from the inspections I perform.
Of course, I'm licensed in the Province of Ontario, Canada
Might be a little different.