Hi, I have a '97 F-150 4.6 with 154,000 miles. I have owned the truck for about 2 1/2 years and it is a great truck but when I get on the highway and get up to about 60 the OD light starts to flash and will keep flashing until the engine is shut of. I don't notice any problem with the truck but I am concerned about the flashing. I took it into the shop last week and they told me no codes were pulled. It was not a Ford shop but a good local shop, could it be that their machine can't read all ford codes? I can take it to the local dealer but just wanted to check and see if anyone else has had this problem. I had a flush done last week but when I got back on the highway I drove about 10 miles and it started flashing again. Any help would be appreciated, I am hoping it doesn't need a new tranny. Thanks in advance for any help.

 

It takes a Ford specific reader to read Ford transmission codes. If they don't have the right reader it will report no codes.

When the OD light flashes a code is stored. You need to find someone that can read that code before it kills your trans.

 

Took my '97 F-150 152K miles, into ford garage to have flashing light checked. Code came up that it needed a VSS. Had Vss put in and after about 10 minutes of driving at 60MPH, the light started flashing again. I tried to use the cruise control and at any speed over 40 MPH the truck will not hold a steady speed while in cruise. It surges up and down by about 5-7 MPH. I took it back to ford garage and no new codes are coming up. I am concerned about driving it on the highway since the light starts flashing at 60MPH, don't want to harm the truck. Do you think that the cruise control which can't hold a steady speed have anything to do with the OD light flashing? I am taking it back to ford to have them replace the vss again but am concerned that they can't find the problem. Any help would be appreciated. Thank you

 

The code really means the signal from the VSS is bad. It does not necessarily mean the sensor itself is bad. It could be a bad tone ring that the VSS is reading, or it could be a wiring problem going to the VSS. It will take some diagnosis to figure out what's wrong.

The cruise control is a symptom, not the problem.

 

Thanks Casey 1 - I had the truck back in the shop today and they found that the gear in the rear end where the vss is installed is out of round so it does not mate up very well. They seem to think that replacing that gear will solve the problem. Thank you for your help.

 

Any word on your truck yet has it been fixed? We have a customer with a similar problem where the OD lisght flashes and the trans shifts funny. It would shift into OD then abrubtly shift out. Our tech found checked everything he could and pin pointed it to something inside the trans that was not working properly, however the customer has a very busy schedule and we havent had a chance to repair the problem.

 

I have a 97 f150 & it is doing the same thing. The light only comes on at speeds over 55 then will go out when the truck is turned off. The codes were 503 & 1500 even when the light is flashing the tranny shifts fine even when shifting in and out of overdrive.

Took it in to ford & they said it was a rear end sensor. changed that & same thing happened. Back in this time they told me it was the sensor on the tranny & told me to test it with a ohm meter should be between 170 & 250 ohms. Mine read 214. The next thing they came up with is that it is picking up a frequency from something like the alt. which causes the code.


My truck does have 33" tires on it & the odometer is off by about 2 tenths
I asked if they thought that could be the problem & they didn't think so. Asked then if there was a problem with the tranny & they didn't thing so

 

97 with oversized tires and stock speedo should not trigger a code. i dont see why. the only speedo related issue is when it gets no signal. usually the culprit there if the speedo gear is fine is the speedo drive gear (plastic gear on shaft) heats up and spins off the retaining ball. which i believe is a 4x4 only trait since 2wd speedo drive gear is actually part of the shaft.

perhaps yours is slipping but hasnt spun off yet? its a quick check, remove tail housing and u can see it. i had to cut the wire and lengthen it, want to make a splice that will fit thru the hole in tail housing.

 

I also have this problem the exact same as described above just wondering if these issues were ever fixed.Thanks

 

i fixed my issue by lathering a lil bit of epoxy on the speedo drive gear as i slid it on the shaft. has yet to come off and i wont take it off unless i have to since i know i'll have to cut it.