Bronco Forum - Full Size Ford Bronco Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
I have an automatic 95 F150 4x4 with a 351W. The other day all of a sudden my speedometer and odometer stopped working, my overdrive light is flashing, and it has a real hard 1 to 2 shift. It all happened at the same time. When i searched online it seemed like it was the vehicle speed sensor. I've since replaced that and the problems haven't gone away.

Can someone please help me as to what i should do next?

Thanks
Bubba
 

·
JEEP CREEP
Joined
·
2,503 Posts
My speedo stopped working and while swapping out my steering column I had the battery disconnected when I hooked it back up it was working. May be a long shot but you could try that
 

·
Super Moderator
Joined
·
26,319 Posts
yo,

There are abour 4 connectors from the ABS Sensor on the 8.8 thru the 4WABS Control Module & then up to da PSOM (Speedo/odometer) and then to the EEC/Cruise Control/ Overhead Console.

Is the Amber ABS Light lit all da time?

Suggest you do a SELF TEST;
COMPREHENSIVE & Connector Location pics, Bronco & Ford; miesk5 NOTE, The self-test plugs were mounted on the passenger side fender on 1985-86 EFI trucks; The self-test plugs are located along the driver's side fender behind the air filter box on 1987-95 EFI trucks
http://fullsizebronco.com/forum/showthread.php?t=44736 by Steve83
Post any codes found here.

Speed Input Signal Test in 93-96 Bronco; "...NOTE: Only wiring harness end of connector is to be probed. * Connect Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent to Pin 4 (speed in ) and Pin 5 (speed in -). * Does the voltage increase smoothly and continuously from 0 to approximately 3.5 volts as vehicle speed increases from 0 to 48 km/h (0 to 30 mph)? OR: If available, a frequency counter may be connected to Pin 4 (Speed in ) and Pin 5 (Speed in -). Does the displayed frequency of the signal increase smoothly and continuously from 0 to approximately 667 Hz at approximately 48 km/h (30 mph)? OR: * If neither a voltmeter nor frequency counter is available, vehicle speed control may be used as a good indicator. If it works normally, then the speedometer module is at least receiving a speed input signal and the wiring and sensor can be assumed to be good. Rear axle sensor should read 800-1400 Ohms across the pins, and more than 10 Ohms from the metal shell to either pin. To bypass the 4WABS module & feed the ABS signal directly to the PSOM, jumper LG/Bk to LG/Y, and R/Pk to O/LB..."
Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/registry/media/170517_1

Use this for F series..check color codes here for the above continuity test
Wiring Diagram in 96 F Series, 92-95 are Similar
Source: by Ford via Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/registry/media/95932_1
Tone Ring Inspection; "Take off the rear diff cover. Check the Ring Tone gear. It is located on the left hand side of the ring gear. Look to see if any of the teeth have been notched (from debris floating around in the diff.) Usually a spider gear. If the ring tone gear has been notched, it will need to be replaced to fix your speedo reading. Jack it up and rotate the tires to look for the teeth to be notched/broken/bent..."
Source: by Bighibbi at FSB


also see same info Plus more in this thread here in FSB http://fullsizebronco.com/forum/showthread.php?t=171136&page=2
 

·
Registered
Joined
·
8 Posts
Discussion Starter #4
The ABS light isn't on. I tried disconnecting the battery after i replaced the vss, but that didnt help either. I went ahead and made sure the vss was screwed on snug and the harness was on properly, but that still didnt help. I went ahead and pulled the codes earlier today and it threw me code 452, which says there is a problem with the vss. So basically im back where i started and dont know what to check next.
 

·
Premium Member
Joined
·
23,549 Posts
how many miles on the rig?

was there alot of metal shavings on the old VSS when you pulled it out?
 

·
Registered
Joined
·
8 Posts
Discussion Starter #6
Theres 173,xxx miles on her right now. Yes when i pulled out the old vss its was covered in metal shavings and when i pulled out the new one today to check to make sure i put it in right, it was already covered in metal shaving too. (I put the new one in yesterday.)
 

·
Registered
Joined
·
75 Posts
i believe the flashing overdrive light and the hard shifts means its in fail safe mode. Save the time and money, take it to the dealer and they will get you up and running in no time.
 

·
Premium Member
Joined
·
23,549 Posts
i believe the flashing overdrive light and the hard shifts means its in fail safe mode. Save the time and money, take it to the dealer and they will get you up and running in no time.
maybe if you have ass loads of money to burn

Theres 173,xxx miles on her right now. Yes when i pulled out the old vss its was covered in metal shavings and when i pulled out the new one today to check to make sure i put it in right, it was already covered in metal shaving too. (I put the new one in yesterday.)
excessive metal shavings on the VSS sensor is a bad sign. pull your diff cover because I bet your going to need a axle rebuild.

if the VSS fills up with shavings it can no longer read the tone ring correctly.
 

·
Super Moderator
Joined
·
26,319 Posts
yo,
Yeak-h, Jopes is on da mark.

Here is the Ford PSOM Pointer Waiver TSB 96-21-11 for 92-96; "..The speedometer needle may waver and or a light surge may occur on some vehicles...This may be due to slight dents/chips in either the exciter ring or the Vehicle Speed Sensor (VSS) and air gaps between the VSS and the exciter ring. Any slight dents, chips, etc., in either the exciter ring or VSS will create needle waver. Measure air gap between the VSS and exciter ring. It should be 0.38-0.51mm (0.015-0.020"). Check exciter ring runout per the same ring gear backface runout procedure of the appropriate model 1996 Powertrain/Drivetrain Service Manual, Section 05-00. Make sure the exciter ring is mounted correctly to the ring gear. If runout is more than 0.1mm (0.004"), perform the differential runout check per the procedure in the appropriate model 1996 Powertrain/Drivetrain Service Manual, Section 05-02A or 05-02D, to find cause and repair as needed. If all items listed above check good, replace the Instrument Cluster Assembly. Obtain the correct service part number from the Parts Catalogue and then contact the Electronic Odometer Exchange Center at (800) 259-9700 for U.S. Dealers and (800) 663-9974 for Canadian Dealers..." read more
Source: by Ford via miesk5 @ http://home.comcast.net/~miesk5/tec...tm#PSOM Pointer Waiver TSB 96-21-11 for 92-96

I messed-up on the 4WABS stuff, I forgot that you have a F 150 so you don't have a 4WABS Sys nor a 4WABS module;
 

·
Registered
Joined
·
1 Posts
What to do?

So I am having the same problem bubba explained and after reading this thread I decided to take off the differential cover. As soon as I did that, out came some bolts, shredded pieces of gear, ect... There is also a gear that you can see in the picture completely loose. I am pretty sure this would cause my speed sensor to mess up :duh. So talking to some mechanics, they tell me the best think I can do is go to the junk yard and get a used differential instead of rebuilding it. What do you guys think?

 

·
Registered
Joined
·
1 Posts
I replaced mine about 3 months ago and its workin great. I am, however having the same issue as you but no shavings at all. The I'm thinking about disconnecting my ABS to see if that takes care of the hard shifting and speed o problem
 

·
Super Moderator
Joined
·
26,319 Posts
1 - 14 of 14 Posts
Top