97 Taurus SHO VSS? No Spedo - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

tunerworld · 06-04-2008, 05:20

I Just bought a 97 SHO Taurus and the owner told me that the VSS (Vehicle Speed Sensor) was bad and needed to be replaced. I bought a Chilton's manual but it doesn't show me where it's located at.

Then i read a forum that said the SHO's don't have VSS modules but use ABS to monitor speed. Is this true or is there a VSS on the tranny. If so, I sure as heck can't find it.

Help! (The Speedo doesn't register any speed at all, sits at 0 and lots of trouble shifting)

**tbird100636** · 06-04-2008, 17:49

97 SHO does speedo, speed control, and trans. shifting based on vehicle speed read by Wheel Speed Sensors and sent out by ABS module. No VSS on Trans. Here's the test procedure:

G1 Check Speedometer
Road test vehicle
Is speedometer operating?
Yes
Go to G2
No
Go to G5

G2 Check The Odometer Reading
drive vehicle over a known distance
Is odometer reading inaccurately?
Yes
Go to G3
No
Go to G4

G3 Check Speedometer Accuracy
Drive vehicle at a steady speed over a 0 km (16 mile) distance and record the total distance travelled.
Does speedometer meet speedometer calibration tolerance specification?
Yes
System OK
No
REPLACE speedometer assembly

G4 Check SARC Vehicle Speed PID
connect Rotunda New Generation Star Tester or equivalent to data link connector C229 beneath instrument cluster.
Access SARC PID: VSS_SRC. Refer to Suspension Control for procedure and entre PID list.
Drive vehicle.
Observe vehicle speed via PID VS_SRC
Does vehicle speed indicated in PID: VSS_SRC reflect approximate vehicle speed?
Yes
Go to G5
No
SERVICE Circuit 679 (GY/BK). Go to Antilock Brakes / Traction Control Systems.

G5 Check Circuit 679 (GY/BK) For Open Circuit
Using an ohmmeter connect one lead to Circuit 679 (GY/BK) at anti-lock brake control module connector Pin C1057 and the other lead to instrument cluster Pin C251, Circuit 679 (GY/BK).
Measure resistance.
Is resistance less than 5 ohms?
Yes
GO to G6.
No
SERVICE Circuit 679 (GY/BK) for open circuit. RESTORE vehicle. RETEST system.

G6 Check Circuit 398 (BK/Y) Ground
Connect ohmmeter to instrument cluster connector Pin C250 , Circuit 398 (BK/Y).
Measure resistance to known good ground.
Is resistance 5 ohms or less?
Yes
GO to G7.
No
SERVICE Circuit 398 (BK/Y) for open circuit. RESTORE vehicle. RETEST system.

G7 Check Clip To Cluster Circuit Connector
Disconnect instrument cluster connectors C250 and C251
Using an ohmmeter, measure resistance of speedometer indicator terminals to printed circuit where they seat.
Is resistance 1 ohm or less at each indicator terminal?
Yes
GO to G8.
No
REPLACE contact clips. RESTORE vehicle. RETEST system.

G8 Check Printed Circuit
Reconnect cluster connectors.
Using an ohmmeter, measure resistance from speedometer contact clips to instrument cluster connector according to chart.
Pin/Clip Function
C251 Power Input (RUN)
C250 Ground
C251 Vehicle Speed Input Signal
Is resistance less than 1 ohm?
Yes
REPLACE speedometer assembly. RESTORE vehicle. RETEST system.
No
REPLACE instrument cluster printed circuit. RESTORE vehicle. RETEST system.
A note, the ABS Module is under the battery tray, make sure there is no acid or corrosion on the module connector terminals.

tunerworld · 06-05-2008, 05:55

Ah! Thank you, I had taken the car to the shop yesterday and they thought they found a VSS (and the engine error code says VSS) but when they ordered the part, it wasn't the right one. I'm going to test this myself and then take it to them if I find the problem. I'm not a great mechanic, but I know how to test electronics :) .... now if it would just stop raining :)

tunerworld · 06-05-2008, 14:02

Ok, so I found the ABS this morning but I can't find where the "instrument cluster" connector is at. Is it somwhere under the dash? My multitester doesn't have leads long enough to go that far. Also, I've seen on other sites that the connections could become corroded and to clean them but mine look fine.

Finally, I'm too much of a newb to have any idea what I would do if the resistance was higher than 5ohm, you said to treat it like an "open circuit" but I don't know what that means.

SHOZ123 · 06-06-2008, 12:48

I would bet the ABS module is bad. Major PITA to change out and no way can you afford a new one. Mine went bad a couple of years ago. First the ABS light would come on and then finally the speedo would drop out. When the speedo drops out the tranny gets real stupid.

You could make sure the ABS connector is clean and tight. You can also test the individual sensors with a voltmeter set on AC and spinning the wheels by hand. But the SHO ABS can use any speed sensor as an input so I doubt if one of them is the problem.

**tbird100636** · 06-06-2008, 17:37

Quote:

Originally Posted by tunerworld

Ok, so I found the ABS this morning but I can't find where the "instrument cluster" connector is at. Is it somwhere under the dash? My multitester doesn't have leads long enough to go that far. Also, I've seen on other sites that the connections could become corroded and to clean them but mine look fine.

Finally, I'm too much of a newb to have any idea what I would do if the resistance was higher than 5 ohm, you said to treat it like an "open circuit" but I don't know what that means.

You have to remove the cluster to access the connectors. Very easy on a console car. Remove the 2 screws on the cluster bezel then pop it out. Cluster is held by 4 screws. If the resistance is over 5 ohms when testing a circuit then this means there is an issue somewhere in the circuit. Using the wiring diagram look for joint connectors in the circuit and disconnect them and test each side of the circuit. An example would be the 679 circuit going to the PCM. Lets say the circuit is open between the ABS module and the PCM only. After the splice going to the PCM is Joint Connector C130. You disconnect it and test from the PCM to C130, and from the opposite side of C130 to the ABS module. Then when you find out which circuit is open you then potentially have to open the harness and find the issue with the wire. Or you could just cut most of that section of wire out and solder in a new wire.

drscore · 06-06-2008, 23:19

I had the same problem on my 97 SHO. It was the ABS module, and it is somewhere that isn't easy to replace (under the battery?). It was not a cheap fix, but had to be done. The car was not driving well.

SHOZ123 · 06-07-2008, 00:00

Indeed. I think the ABS pump/module is the first part they start with on the car :)

You may be able to just replace the front part which is the electronics. If you can it really not that bad. I could not get the middle bolt out and broke two T30 bits trying. And the 4 smaller torx bolts on the corners are some of the softest metal know to man.

To remove the whole thing is much more work. :(

**tbird100636** · 06-07-2008, 11:16

Quote:

Originally Posted by SHOZ123

Indeed. I think the ABS pump/module is the first part they start with on the car :)

You may be able to just replace the front part which is the electronics. If you can it really not that bad. I could not get the middle bolt out and broke two T30 bits trying. And the 4 smaller torx bolts on the corners are some of the softest metal know to man.

To remove the whole thing is much more work. :(

I've had similar experiences with Chrysler ABS Modules on Trucks. You have to hammer on the end of the screwdriver to get a better bite when turning the screw. After a few shots for the hammer grasp the screwdriver and push down on the screw while loosening. If you get it right it will break loose and come out.

SHOZ123 · 06-07-2008, 12:57

Well you aren't going to do that with a SHO ABS pump. You can barely get a wrench on it.