Speedo shut off OD light flashing

1qwik99

Registered User
Hey guys,

On the way back home on the FWY the speedo stopped working and the OD light started flashing. No check light. Any Ideas? I replaced the speedo / trip gear about a year ago and all has been fine since till now.
 
That talks about the flashing OD but not the speedo unless they two are connected which is what I suspect since they both went out at the same time. Don't remember any deep pot holes though :)
 
The speedo is electric, so....

I'd focus on the trans according to the light and then see if that also cures the speedo - you might find a wiring issue that affects both, such as a bad ground, perhaps.
 
I just saw another post about the V.S.S. which plugs into the trans. Maybe the gear broke or the sensor went out.
 
Checking underneath/there sounds like a good place to start. Good luck and keep us posted.
 
Speedo out

I checked for engine codes with my Ford OBD-1 tool and got a 452 which translates to: "No input from Vehicle Speed Sensor (VSS)" I guess that is at least part of the problem. Are there any gears that activate that sensor that may also be part of the problem? Thanks
 
The VSS has a speedometer gear attached to it, which rides on the drive gear on the transmission output shaft.
 
Speed VSS

Is there a difference between a VSS and an OSS sensor? I am getting a 452 code and the speedo is out along with the OD light flashing. This happened as I exited the FWY so the cruise was no longer set and the car seemed to shift ok. I had control of the OD button but the light still flashed.

Thanks

95 SC AT
 
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The sensor you need to look at is located on the transmission where the speedometer cable normally attaches. It is either the VSS sensor or the speedometer gear attached to the VSS sensor. The VSS feeds input to the speedometer and EEC. The VSS also provides an input to the cruise control module. The OSS sensor is also used in autos to directly measure transmission output shaft speed.


Is there a difference between a VSS and an OSS sensor? I am getting a 452 code and the speedo is out along with the OD light flashing. This happened as I exited the FWY so the cruise was no longer set and the car seemed to shift ok. I had control of the OD button but the light still flashed.

Thanks

95 SC AT
 
The VSS (vehicle speed sensor) and OSS (output shaft speed sensor) are different sensors. The first thing I'd do is pull the VSS from the transmission and inspect the connector for dirt and such and inspect the gear for signs of excessive wear. It's in a tight spot but it's doable without much headache.
 
VSS issue

The sensor you need to look at is located on the transmission where the speedometer cable normally attaches. It is either the VSS sensor or the speedometer gear attached to the VSS sensor. The VSS feeds input to the speedometer and EEC. The VSS also provides an input to the cruise control module. The OSS sensor is also used in autos to directly measure transmission output shaft speed.

Is the gear sold separately? I don't see it as part of the VSS. The part number I am referring to is Motorcraft #DY588

Thanks
 
Yes the gears are sold separately and vary based upon the gears in your Diff. I had a similar issue on my Cougar turned out the VSS was lose, tightened the retaining bolt and went away.
 
VSS issue

Hey all !

Just to let you know, I went to Oreily's and picked up a genuine Motorcraft Speed Sensor, removed the gear, reinstalled the gear and installed the new sensor. Works like a charm! Fixed both the flashing O/D light and speedo inop. situation. Thanks to all of you for your help. DYI saved me about $180.00. YouTube had a video on the procedure on a Mustang which was basically the same.
 
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