No speedometer, OD flashing???
 

Hello guys,

I've seached the forum at length, and can't find any new answers to this problem.

This morning, my 2001 F350 4x4 7.3L PSD automatic started acting funny. No speedo, and OD light on the shifter blinking. VSS was the first thought. I drove the truck to the dealership and bought the sensor. On the way home, the truck died driving down the highway. I got it restarted, about 75 times (really) and finally got it home and in the garage. It would run for 10-15 seconds and then die suddenly. No tach while cranking.

I replaced the VSS, and bought a new CPS from the Ford dealer. Replaced both this morning. Truck seems to run fine now, but I still have no speedo at any speed, and the OD light is blinking steadily. There is no ABS light on.

After searching the forum, I'm going out to check the wiring in the steering columm right now. All fuses in both fuse boxes check good.

Any suggestions on where to look next? Truck has me spooked right now. Afraid to drive it any long distance after this morning's repeated dying episode. Seriously, I probably had to restart it 75 times just to get home.

Thanks in advance for the help.

Stacey

Pulled the bottom cover off the steering column, and although I don't know exactly what I'm looking for, the wires look OK. I don't see any nicked or broken wires.

Oh, and I read somewhere on here about turn signals not working. The turn signals work fine.

Stacey

Search forum for speed sensor replacement. i believe that might be the cause fro the speedo not working/OD light flashing. Good Luck!

did you make sure the ground wire on top of the VSS was connected securely?

Other than that you've done everything right so far.

Keep us posted

I hate to tell you but the flashing OD light is the first sign of a tranny going south, hope I'm wrong. Pull the fuse under the hood for the PCM and re-install it, this will reset the PCM and the flashing OD light will go out. If it stays out...good.

Check all fuses under hood and under the dash for the speedo.

Check the wireing to the VSS. These have been know get a little rot on the pins and sockets. Pull on the harness end for loose connections.

Cuda_Jim are you thinking that maybe the torque converter is not unlocking and that's why all the stalling?

I think there is another speed sensor in the trans. Maybe that one went bad although it is much more common for the one you changed

Took it into a trans shop earlier today. The code was the VSS. He ran the diagnostics while driving the truck, and the two trans sensors are working correctly. The VSS on the diff was not working. I replaced the VSS again this afternoon with another new sensor, and it's still not working.

I checked the wires from about 6" away from the connector, reading the pins inside the connector, and have continuity from both wires to the pins. I read continuity when I place probes on each pin on the wiring harness that plugs into the VSS. I'm stumped.

Broken wire somewhere? I've tried to trace the wires back under the hood, and good grief....what a mess of wires. Could someone tell me where the two wires from the VSS go? I'll run new wires if I have to, just to eliminate a broken wire problem.

All help appreciated.

Thanks,
Stacey

Oh, and where is this ground wire on the VSS? I don't see any other wires going anywhere around it, except the two-pin plug that plugs into the sensor. The ground wire under the hood, behind the driver's side battery is firmly connected.

Anxiously awaiting...

Stacey

Is there a relay or anything under the hood that has anything to do with the VSS? I've tried everything, and no luck.

Any wierd things that might cause this?

I need to drive this truck to Atlanta this next week, and I don't want to take off on a 4-hour drive with it acting like this.

Thanks again,
Stacey

I seem to remember someone suggested changing out the rear in lube here on the forum.. Maybe you have a bunch of metal shavings and messing up the VSS.

The electronic speedometer receives a speed signal from the 4WABS module (if equipped with 4WABS) or the generic electronic module (GEM)/central timer module (CTM) (if equipped with RABS)

01's have 4WABS and in the event of VSS failure the OD light will blink but Speedo will be driven off a front wheel sensor. Hang tight and let me dig a little.

Update:

OK, Changed the differential fluid (Mobil 75-140 synthetic) and added some LS additive, and now the speedo works, but the OD light is still flashing. I disconnected both negative battery terminals, and I'm going to let it sit for about 15 minutes to clear any codes and see if the OD comes back on.

Everything seems to work fine. Even with the OD button flashing and the tranny in overdrive, when I push the OD button, it shifts back into 3rd. Push it again, and back to overdrive.

Maybe clearing the codes will solve all this...

Thanks,
Stacey

My 99 F250 deisel did the same thing, flashing o/d light first and then no speedo. I replaced the the VSS in the rear diff and it fixed my problem completely. I was told that that truck has 3 Vss on it and the Ford dealer stocks more of the rear diff VSS because that goes bad more often.
Kevin
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99 F250 Superduty 4x4 crew
95 F350 Dually Flat Bed
63 F100 Project
29 Ford Sedan Delivery

When you turn the OD off, is the light still blinking?
If yes, then I'm sorry but I'll have to agree with Cuda_Jim on this one that your tranny is going south.

Kwik, A locked up converter would only cause stalling in stop and go instances. He stated that it stalled on the highway ("75 times"). You'd have to slow waaaaaaay down for a locked converter to stall the motor. Unless it was stuck in a higher gear, like 3rd and slowing down to 10-15 mph.