Gen3 SHO almost made it home by 2 miles, then P0500 and only 1st gear

[Qshiplvr]

Well tried driving the Gen3 home after a major maintenance and Cobra brake upgrade w/ bias plugs installed. Almost made it home, when on the freeway going 75 mph, suddenly the revs kick up, speedo goes to 0, and O/D OFF light starts blinking. I’m going like WTF just happened? I was almost to the offramp and took it because didn’t want to be stranded on I-10 with outside temps at 110 F. Driving streets reving about 3K in 3rd, I figured I was about the speed limit. When I stopped at a traffic light, I put it in park, set the parking brake, keyed off, restarted and SES light came on, and my Scangauge threw a P0500 code. OK. Didn’t know what that was, but figured it was electrical, because my AX4N was rebuilt about 5000 miles ago and upspeced to “almost road ripper” quality (the shop owner died shortly after I got my tranny back in the car, so can’t ask him exactly). The trans shifted fine, so probably not mechanical.

Anyway, got to another light, decided to try the shift into park, key off and back on again, and wouldn’t you know, it made everything WORSE! Now I couldn’t get out of 1st gear! So pulled off to a side street, called AAA and burned a tow for 1.8 miles to home.

So here are the clues:

Relatively freshly rebuilt AX4N only 5K on the rebuild, shifts fine
Sudden loss of speedo to zero, never came back
O/D OFF light flashing while on freeway, when keyed off, never came back
P0500 code on Scanguage

Previously my Cruise control went away and I could never get it to work again. No biggie, I’ll just drive w/o Cruise. I suspected something may be up w/ ABS module because the light kept coming on intermittently then extinguishing at random

JohntheSHOguy told me when I key on, the ABS light should be one of the lights that come on at startup and when i just went out to check, sure enough, no ABS light, so probably burnt out bulb

Somebody posted that he checked his ABS fuse and it was blown. Is that the one in the engine compartment power distribution block or is the the fuse panel under the driver side steering column above the parking brake? Also, should I be checking other fuses?

Under the driver side dash fuse panel:
I think there is a 5 amp mini fuse #24 that controls ICP, RCC, speedometer
There is also a 10 amp mini fuse #9 labelled ABS

Front engine compartment power distribution block:
30 amp mini fuse ABS #18
40 amp m-a-x-i fuse ABS #13

Any input would be greatly appreciated!

 

[gamefanatic]

Check the fuses first in the engine bay. But this sounds like a bad wheel sensor. Back probe the sensors at each wheel with a multimeter, while spinning the wheel and see if you get a good signal or not.

 

[Texas Marauder]

Vehicle Speed Circuit Check

P0500: CHECK VEHICLE SPEED PID​

• Diagnostic Trouble Code (DTC) P0500 indicates the powertrain control module (PCM) detected an error in the vehicle speed information received from the anti-lock brake system (ABS) control module, generic electronic module (GEM) or central timer module (CTM).

There are 4 fuses that affect the ABS. If the fuses are good and you don't get an ABS check light on the instrument cluster, the ABS module is probably bad.

 

[Qshiplvr]

Vehicle Speed Circuit Check

P0500: CHECK VEHICLE SPEED PID​

• Diagnostic Trouble Code (DTC) P0500 indicates the powertrain control module (PCM) detected an error in the vehicle speed information received from the anti-lock brake system (ABS) control module, generic electronic module (GEM) or central timer module (CTM).

There are 4 fuses and a relay that affect the ABS. If the fuses are good and you don't get an ABS check light on the instrument cluster, the ABS module is probably bad.

View attachment 95038

View attachment 95039

View attachment 95040

When I key on, this is what my dash looks like. I believe I SHOULD see an ABS yellow (amber) light show up somewhere in the yellow circle upon key ON position, but since it is missing, I am guessing the bulb is burned out?

 

[Texas Marauder]

You should see the ABS light prove out every ignition cycle. The warning light is probably an LED. Regardless, from the service manual:
The indicators are not serviceable separately.

 

[Qshiplvr]

I saw this on eBay: Based on what I've read elsewhere on the forum, the ABS module is SHO specific, yet this eBay listing says it is compatible w/ Mercury Sable and other Tauri. Can anyone confirm if this ABS is SHO compatible?

 

[Qshiplvr]

I saw this on eBay: Based on what I've read elsewhere on the forum, the ABS module is SHO specific, yet this eBay listing says it is compatible w/ Mercury Sable and other Tauri. Can anyone confirm if this ABS is SHO compatible? View attachment 95042

View attachment 95043

It's odd...I ran across this eBay listing, and it seems to use the EXACT same picture as the eBay listing I found back on 2017, same tear in the NOS box and everything...

Here's the post from 2017:

 

[Qshiplvr]

I am doing a kind of post-mortem analysis of the failure mode to possibly point to a diagnosis of the problem. See if you agree with my findings

Mechanic performed the following upgrades:

Installed 13” Baer brake front disc upgrade w/ new pads
Installed bias plug mod
Replaced lower control arm and tie rod ends
Replaced front wheel bearings
Replaced coolant overflow tank
Changed oil & filter
Repaired broken shim, got motor running again

Driving back from mechanic’s place, SHO drove great. 70 miles of fwy driving no problem

10 miles to go on I-10, driving 75 mph:

4th gear lost
RPM spikes to 3500-4000 rpm (3rd gear on fwy)
“O/D OFF” green light flashes, even though I never touched the gear lever

Exit I-10 fwy to drive on city streets

5 miles to go on Hwy 111:

While driving in 3rd gear shifting from DO to D, then back to DO has no effect
Shifting from DO to N, then back to DO has no effect

Still only running in 3rd gear

4 miles to go, stopped at light, Shift into Park, key off, re-start, shift into DO

O/D OFF light goes away (never comes back on) still only drives in 3rd gear

Continue to drive city streets to get home

2 miles to go, stopped at light, Shift into Park, key off, re-start, shift into DO

Now 4th, 3rd & 2nd gear gone, will not shift out of 1st gear

Drive off main drag and park, call AAA and tow back home 1.8 miles

The fact that I drove 70 miles w/o incident, then having the trans/shifting progressively fail from losing 4th, then all at once, 3rd, and 2nd after key off, restart and driving 8 more miles leads me to believe this isn’t a fuse/relay failure, but possibly a sensor/wire or ABS computer failure. Also, would a VSS failure likely be progressive or binary (all at once)? For those with a more complete understanding of how the ‘99 SHO transmission operates, please enlighten me with your opinions / analysis. Any input would be greatly appreciated.

 

[gamefanatic]

Well this is typically a loss of VSS signal. Seeing fron wheel bearings where done recently, check the sensor there first as it could have been damaged. However, rears are the most common problem.

 

[Texas Marauder]

Do you have access to a diagnostic tool or FORScan? Scangauge will only read OBD codes. You need to read all codes. Otherwise you're just guessing.

The fact that the ABS light doesn't prove out or work tells me it's more than an ABS sensor.

 

[Qshiplvr]

Do you have access to a diagnostic tool or FORScan? Scangauge will only read OBD codes. You need to read all codes. Otherwise you're just guessing.

The fact that the ABS light doesn't prove out or work tells me it's more than an ABS sensor.

I bought a scan tool called Thinkcar. Never got a chance to use it. I guess now is a good time to start.

 

[Texas Marauder]

Since 99 was in the early stages of networking modules, hopefully you can get some useful information from your scan tool.

I revised my earlier post to show the correct fuse panels and wiring diagram for 99MY.

 

[Qshiplvr]

Since 99 was in the early stages of networking modules, hopefully you can get some useful information from your scan tool.

I revised my earlier post to show the correct fuse panels and wiring diagram for 99MY.

View attachment 95047

View attachment 95048
View attachment 95049
View attachment 95050
View attachment 95051
View attachment 95052

OK, after MD appt, was able to plug in OBDII scantool Thinkcar and it pulled these codes. I haven’t had time to go thru them as need to get to work, but it’s a start:

U1341
U2005
B1600
B2103
U1262
P0500
P1000
P1502
P1260
B1522

Thinkcar is a POS scantool. I think it is just a way to siphon money to the maker selling you upgrade modules and hardware. I’m going to have to spring for a REAL scan tool. I need it to diagnose a multitude of cars: 1999 SHO, 2005 Mitsu Lancer Ralliart 2.4l NA, 2008 Lexus ES350 and 2008 Vette LS3. Any suggestions from all the h*a*r*d*c*o*r*e diagnosticians out there?

 

[gamefanatic]

My first suggestion is to always go with the cheapest option. I recommend ObdLink MX+. Okay, so it's not the cheapest, but it will get the job done on nearly any car as it's software agnostic.

Then follow that up with Forscan from https://forscan.org. It can do just about 80-90% of anything you are going to want to do with Ford and compatibles (Mazda,etc). Windows (preferred), Android / iOS.

Trying to support all the other vehicles, my first option would be to go with Torque (Android / iOS).

Torque — OBD2 Performance and Diagnostics for your Vehicle

torque-bhp.com

If you want something that is stand-alone and tries to be the all-in-one and is "new", I'd probably recommend something by TopDon these days. I've had pretty good luck with their devices.

Diagnostic Tools

Your trusted partner for automotive tools: diagnostic tools, battery chargers, battery testers, TPMS, jump starters, key programmers, thermal imaging, ADAS, and EV Chargers.

www.topdon.us

Keep in mind you pay more for those tools as they are a computer / screen / battery all-in-one before you get to the software. Take your pick of the devices only based on your budget... Some will have paid updates, others will include the updates depending on the target audience.

 

[gamefanatic]

Sounds like you've got something disconnected, pinched or dead...
Check the simple stuff, power, fuses, disconnected cabling.


U1341 - Loss of communications...



Once you are sure there is no power or wiring issue...

P0500 - VSS Signal (as noted before bad or no signal)
P1502 - Vehicle Speed Sensor no signal from ABS (Top Repair is to replace)

P1260 - Anti-Theft transceiver
B1600 - Ignition Key Responder bad or no signal. (Top repair replace Anti-Theft Transceiver)
B2103 - Anti-Theft tansceiver (Check antenna)
U1262 - SCP Bus fault (Check Fuse Box under dash for bad fuse or wiring issue)

B1522 - Hood Switch (bad switch or shorted)

 

[ScotSHO]

Forscan works great on all OBDII Ford cars and is free

 

[Qshiplvr]

Do you have access to a diagnostic tool or FORScan? Scangauge will only read OBD codes. You need to read all codes. Otherwise you're just guessing.

The fact that the ABS light doesn't prove out or work tells me it's more than an ABS sensor.

FORScan run using OBDII LinkEX dongle USB A connected to Windows laptop running Win 10 Pro
08-10-25

This is the log output of the OBDII LinkEX:

===PATS DTC B1600===
Code: B1600 - The PATS key has not been read successfully.

Module: Passive Anti-Theft System

Diagnostic Trouble Code details

At some time since last clear the ignition was switched on without any key code being read.

===END PATS DTC B1600===

===PATS DTC B2103===
Code: B2103 - No Signal detected at PATS module from transceiver. (Antenna not connected from transceiver)

Module: Passive Anti-Theft System

Diagnostic Trouble Code details

PATS transceiver circuit fault.

===END PATS DTC B2103===

===PATS DTC U1262===
Code: U1262 - SCP Data Link Fault

Module: Passive Anti-Theft System

Diagnostic Trouble Code details

SCP Data Link Fault

Operator Action

Run self test.

All CMDTCs

Fix all relevant DTCs then clear codes and retest.

Note:

DTCs that start with 'U' are faults which occur during module-to-module communication.

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

===END PATS DTC U1262===

===RCC DTC U1341===
Code: U1341 - Vehicle speed signal missing or incorrect

Module: Remote Climate Control

Diagnostic Trouble Code details

Vehicle speed signal missing or incorrect

Operator Action

Run self test.

All CMDTCs

Fix all relevant DTCs then clear codes and retest.

Note:

DTCs that start with 'U' are faults which occur during module-to-module communication.

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

===END RCC DTC U1341===

===RCC DTC U2005===
Code: U2005 - Audio Integrated Control Panel Unit is not responding

Module: Remote Climate Control

Diagnostic Trouble Code details

Audio Integrated Control Panel Unit is not responding

Operator Action

Run self test.

All CMDTCs

Fix all relevant DTCs then clear codes and retest.

Note:

DTCs that start with 'U' are faults which occur during module-to-module communication.

Modules should never be replaced based only on a 'U' code. These codes do not always indicate a problem, and can be caused by normal diagnostic functions, carried out on the vehicle.

===END RCC DTC U2005===

===OBDII DTC P0500-C===
Code: P0500 - VSS sensor circuit fault.

Status (-43):
- Confirmed - malfunction is confirmed

Module: On Board Diagnostic II

Diagnostic Trouble Code details

VSS sensor circuit fault.

Open VSS circuit.

Shorted VSS circuit.

This DTC may be caused by :

Suspect VSS.

Worn or Damaged VSS drive gear on transmission output shaft.

Suspect PCM.

Faulty or damaged instrument cluster module.

===END OBDII DTC P0500-C===

===PCM DTC P0500===
Code: P0500 - VSS sensor circuit fault.

Module: Powertrain Control Module

Diagnostic Trouble Code details

VSS sensor circuit fault.

Open VSS circuit.

Shorted VSS circuit.

This DTC may be caused by :

Suspect VSS.

Worn or Damaged VSS drive gear on transmission output shaft.

Suspect PCM.

Faulty or damaged instrument cluster module.

===END PCM DTC P0500===

===PCM DTC P1000===
Code: P1000 - On-Board Diagnostic (OBD) Systems Readiness Test Not Complete

Module: Powertrain Control Module

Diagnostic Trouble Code details

On-Board Diagnostic (OBD) Systems Readiness Test Not Complete

Follow the routines in the service manual to resolve the DTC listed.

===END PCM DTC P1000===

===PCM DTC P1502===
Code: P1502 - Vehicle speed sensor signal intermittent

Module: Powertrain Control Module

Diagnostic Trouble Code details

Vehicle speed sensor signal intermittent

This DTC may be caused by :

Short circuit

Open circuit.

Possible causes are:

VSS

PCM

Harness wiring

Worn or Damaged VSS drive gear on transmission output shaft.

Refer to the workshop manual for further diagnosis and repair.

Follow the routines in the service manual to resolve the DTC listed.

===END PCM DTC P1502===

===PCM DTC P1260===
Code: P1260 - Engine disabled by PATS

Module: Powertrain Control Module

Diagnostic Trouble Code details

THEFT Detected, Vehicle Immobilized.

This DTC may be caused by :

Suspect PATS module.

Suspect circuit fault between PCM and PATS.

Suspect PCM.

===END PCM DTC P1260===

===RAP DTC B1522===
Code: B1522 - Hood switch circuit failure

Module: Remote Anti-Theft / Personality Module

Diagnostic Trouble Code details

Hood switch circuit failure

===END RAP DTC B1522===

 

[Qshiplvr]

Do you have access to a diagnostic tool or FORScan? Scangauge will only read OBD codes. You need to read all codes. Otherwise you're just guessing.

The fact that the ABS light doesn't prove out or work tells me it's more than an ABS sensor.

I'd like to note something the mechanic told me when I went to pick up the car: "I POWER WASHED the engine bay to make it look nice"...while I appreciate his meticulousness and attention to detail wanting me to have an "as new" car back after all his hard work, I'm thinking the power washing may have gotten moisture into the ABS connector, and it took driving 70 miles at fwy speeds to dry out the connector and start just enough corrosion to make the pins go intermittent / out to cause all my VSS codes and weird behavior. I say this due to this post on the V8SHO.com board where a commentor mentioned weird speedo behavior due to bad connector pin oxidation at the ABS module under the battery tray (BTW we replaced the battery w/ a new one when I picked it up) since the ABS module connector is forward facing: https://www.v8sho.com/SHO/Intermittent Speedo.htm

 

[Qshiplvr]

Well this is typically a loss of VSS signal. Seeing fron wheel bearings where done recently, check the sensor there first as it could have been damaged. However, rears are the most common problem.

What is the correct part number for the VSS on a '99 SHO? Rockauto seems to sell a couple of different versions (the plugs are obviously different), so can't really tell which one will fit a '99 SHO AX4N transmission.

 

[gamefanatic]

What is the correct part number for the VSS on a '99 SHO? Rockauto seems to sell a couple of different versions (the plugs are obviously different), so can't really tell which one will fit a '99 SHO AX4N transmission.

These don't have a VSS on the tranny. That's available only othe non-ABS models.

They are at each wheel so look at the ABS Wheel Speed sensors. There are too many to list.

Its unfortunate the mechanic power washed the engine bay. Unfortunately these older connectors don't handle this well (ask me how I know) as newer cars which have good insulation at the back of the connector as well as the connector its self.