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

[Texas Marauder]

Use your scan tool or FORScan to read the ABS sensor speed values. Rock Auto shows to have the ABS sensors. Disconnect the ABS module connector and blow it dry. Spray some contact cleaner on the connector and the socket. Blow dry again. IMO, don't load it up with dielectric grease. People seem to go crazy with that. You can put a thin coat of dielectric grease on the seal of the connector.

 

[Qshiplvr]

Use your scan tool or FORScan to read the ABS sensor speed values. Rock Auto shows to have the ABS sensors. Disconnect the ABS module connector and blow it dry. Spray some contact cleaner on the connector and the socket. Blow dry again. IMO, don't load it up with dielectric grease. People seem to go crazy with that. You can put a thin coat of dielectric grease on the seal of the connector.

View attachment 95136

========================
Diving in

Took the opportunity of the cold wave hitting PS (only a high of 102 today) to work on the Gen3 SHO

Looked under the driver’s side dash at the fuse box, I pulled ABS fuse #9 10A and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.


ABS 10A mini fuse pulled from fuse block located under driver's side dash over parking brake pedal

Next popped the hood and removed the brand new Interstate Battery (2 wks old) because I was going to be fooling with the power distribution block high power fuses and manual said it was a good idea to disconnect the battery, so I did.

Son-of-a-gun this car drained a BRAND NEW (I trickled charged it until it was 100% before installing it 2 wks ago at mechanics house before driving it 70 miles home) 2 week old battery down BELOW 80%! Just sitting parked! So that means I’m going to let it trickle overnight in the tool shed tonight before re-installing it tomorrow (because I live in a condo w/ a carport, and don't have a dedicated garage).

On to the high-powered fuses. Opened the power distribution block, pulled the 40 amp ABS M.A.X.I. (gatekeeper software doesn't like the term) fuse #13 and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.


Pulling out the ABS 40A M.A.X.I. fuse (I use periods due to gatekeeper software redaction otherwise)


Finally pulled the 30 amp ABS mini fuse #18 and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.


ABS 30A mini fuse #18


So I’ve systematically eliminated the fuseable links as possible source of the electrical gremlins, that only now leaves the main ABS unit and connector.

The ABS unit is located UNDERNEATH the battery tray, which is held in place by 4 x 10mm bolts. What isn’t obvious is there is a covered power sub-block clipped on to the right side of the battery tray that you need to wrangle loose, and there is a ball-tipped prong attached to the airbox that pokes thru a rubber grommet at the top right corner of the battery tray to hold it steady in place that is a bee-atch to unfasten. You need to lift from the bottom left corner up first, then tilt and rotate so you can un-fasten and push out the ball-tipped prong from its rubber grommet. Once I got the tray out, I was faced with a 10mm hex nut locking down thru the center of the harness plug the ABS wiring to the control unit.


Power sub block on right under 2 clips that is held in place by battery tray, need to wrangle it away while staying attached



Rubber grommet on battery tray



Ball tipped prong attached to airbox that fits into rubber grommet on battery tray

I noticed that there is a protective plastic cap on top of the connector that is held down by 4 grooved slats w/ a clip at the end. One of the slats was OUTSIDE its grooves, and it could have twisted the connector or caused it to have a sufficiently tenuous connection to go hinky (I’m hoping). I start wrenching, and wrenching, and wrenching, and wrenching…this plug is in there good! Took a good number of turns to back out that bolt, and I FINALLY got the plug separated. I doused both the male side (connected to the car) and female side with DeOxitD5 and separated the top protective cap then re-installed w/ all 4 grooved slats correctly seated and clipped down before re-attaching the two halves of the ABS controller plug and wrench back together.


What I saw after lifting out the battery tray


Notice left plastic guide outside of tracks compared to right side and how left side of plug is slightly higher


Unfastened ABS Controller plug after many, many, many cranks on the 10mm hex center lock nut


Better focus on male side plug ABS controller


Female side of ABS controller plug


DeOxITD5 doused male plug on ABS controller


1999 (SHO only) ABS controller part number stamped on Bosch 927


I replaced the battery tray, and put everything away, waiting for the trickle charge to come back up to 100% (hopefully overnight will do it, otherwise I will have to wait another week to get back under the hood).


Back together for now, waiting on trickle charger to top up battery for re-install and testing

TO BE CONTINUED…

 

[Qshiplvr]

========================
Diving in

Took the opportunity of the cold wave hitting PS (only a high of 102 today) to work on the Gen3 SHO

Looked under the driver’s side dash at the fuse box, I pulled ABS fuse #9 10A and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.

View attachment 95204
ABS 10A mini fuse pulled from fuse block located under driver's side dash over parking brake pedal

Next popped the hood and removed the brand new Interstate Battery (2 wks old) because I was going to be fooling with the power distribution block high power fuses and manual said it was a good idea to disconnect the battery, so I did.

Son-of-a-gun this car drained a BRAND NEW (I trickled charged it until it was 100% before installing it 2 wks ago at mechanics house before driving it 70 miles home) 2 week old battery down BELOW 80%! Just sitting parked! So that means I’m going to let it trickle overnight in the tool shed tonight before re-installing it tomorrow (because I live in a condo w/ a carport, and don't have a dedicated garage).

On to the high-powered fuses. Opened the power distribution block, pulled the 40 amp ABS M.A.X.I. (gatekeeper software doesn't like the term) fuse #13 and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.

View attachment 95205
Pulling out the ABS 40A M.A.X.I. fuse (I use periods due to gatekeeper software redaction otherwise)


Finally pulled the 30 amp ABS mini fuse #18 and tested w/ Fluke meter for continuity, tested fine. Sprayed DeOxitD5 on prongs and replaced.

View attachment 95206
ABS 30A mini fuse #18


So I’ve systematically eliminated the fuseable links as possible source of the electrical gremlins, that only now leaves the main ABS unit and connector.

The ABS unit is located UNDERNEATH the battery tray, which is held in place by 4 x 10mm bolts. What isn’t obvious is there is a covered power sub-block clipped on to the right side of the battery tray that you need to wrangle loose, and there is a ball-tipped prong attached to the airbox that pokes thru a rubber grommet at the top right corner of the battery tray to hold it steady in place that is a bee-atch to unfasten. You need to lift from the bottom left corner up first, then tilt and rotate so you can un-fasten and push out the ball-tipped prong from its rubber grommet. Once I got the tray out, I was faced with a 10mm hex nut locking down thru the center of the harness plug the ABS wiring to the control unit.

View attachment 95207
Power sub block on right under 2 clips that is held in place by battery tray, need to wrangle it away while staying attached


View attachment 95208
Rubber grommet on battery tray


View attachment 95209
Ball tipped prong attached to airbox that fits into rubber grommet on battery tray

I noticed that there is a protective plastic cap on top of the connector that is held down by 4 grooved slats w/ a clip at the end. One of the slats was OUTSIDE its grooves, and it could have twisted the connector or caused it to have a sufficiently tenuous connection to go hinky (I’m hoping). I start wrenching, and wrenching, and wrenching, and wrenching…this plug is in there good! Took a good number of turns to back out that bolt, and I FINALLY got the plug separated. I doused both the male side (connected to the car) and female side with DeOxitD5 and separated the top protective cap then re-installed w/ all 4 grooved slats correctly seated and clipped down before re-attaching the two halves of the ABS controller plug and wrench back together.

View attachment 95210
What I saw after lifting out the battery tray

View attachment 95211
Notice left plastic guide outside of tracks compared to right side and how left side of plug is slightly higher

View attachment 95212
Unfastened ABS Controller plug after many, many, many cranks on the 10mm hex center lock nut

View attachment 95213
Better focus on male side plug ABS controller

View attachment 95214
Female side of ABS controller plug

View attachment 95215
DeOxITD5 doused male plug on ABS controller

View attachment 95216
1999 (SHO only) ABS controller part number stamped on Bosch 927


I replaced the battery tray, and put everything away, waiting for the trickle charge to come back up to 100% (hopefully overnight will do it, otherwise I will have to wait another week to get back under the hood).

View attachment 95217
Back together for now, waiting on trickle charger to top up battery for re-install and testing

TO BE CONTINUED…

08/17/25

Battery back at 100%, dropped in, scanned and…

Thinkcar says no ABS installed. I believe the ABS control module is dead

Cleared the codes and went for a spin.

Immediately, the “O/D Off” green light is flashing. Good news is the car shifts through all 3 gears, but it is acting confused. Kick down doesn’t really work. Also, no speedo (stuck at 0 mph). On key on, no ABS light prove pretty much confirms the ABS control module is not talking at all, as Texas Marauder speculated.

When I called up MPH in the Scanguage, it also shows 0mph which makes sense. If the Thinkcar couldn’t detect the presence of the ABS module thru the OBDII port, then there is no mph signal coming from VSS.

So now I am stuck trying to find a mechanic that will install a used ABS controller for me. Supposedly it is in good working condition. Hopefully installing a new ABS Controller will bring this car back to driveable.

 

[GEN 3 SHO FAN]

The speed is calculated with the informations from the abs sensors.

IIRC the ABS module for the SHO isn't the same for SLO (-> be very careful with Ebay and Amazon crossnumber system...) and they were able to manage a faulty abs sensor (no speedo = faulty module > faulty sensor). It could be not related to the wash too...

Also note that there were discussion that SHO ABS modules were differents between years too 96-97 vs 98-99.

Just to be sure, the number you need if you have to buy one is F8DC-2C346-BB, NOT F8CD-2C346-AB and new, they will have a yellow "SHO only" sticker (as your's).
(For others owners 1996-97 is F6DC-2C286-BA IIRC)

If its the module is going bad, most of the time, its the small internals soldering that just gives up. They can be repaired also (maybe less risky). According on what Im seeing on my photos, you don't have to unbolt all the module (and hoses) to repair them, only the missing part on the 2nd photo and part at the right on the 3rd. (No towing, no additionnal unwanted engine pressure washing, just small soldering in half of the box.)

I din't do this job myself, I'm just watching my bunch of archives photos so wait for a veteran to confirm what I'm saying for more security.

Keep us informed,

 

[Qshiplvr]

08/17/25

Battery back at 100%, dropped in, scanned and…

Thinkcar says no ABS installed. I believe the ABS control module is dead

Cleared the codes and went for a spin.

Immediately, the “O/D Off” green light is flashing. Good news is the car shifts through all 3 gears, but it is acting confused. Kick down doesn’t really work. Also, no speedo (stuck at 0 mph). On key on, no ABS light prove pretty much confirms the ABS control module is not talking at all, as Texas Marauder speculated.

When I called up MPH in the Scanguage, it also shows 0mph which makes sense. If the Thinkcar couldn’t detect the presence of the ABS module thru the OBDII port, then there is no mph signal coming from VSS.

So now I am stuck trying to find a mechanic that will install a used ABS controller for me. Supposedly it is in good working condition. Hopefully installing a new ABS Controller will bring this car back to driveable.

08/26/25 (Update and resolution)

Found a local mechanic that installed the salvaged ABS controller from ‘98 SHO. They took off the brake lines and swapped in the controller unit, bled the brakes, buttoned everything back up, and gave it an alignment (JohntheSHOguy replaced tie rods so geometry was altered, needed an alignment).

The write up showed the following codes: P0500, P1000, P1502

Got the SHO back today, and it appears to drive normally. No “O/D OFF” light, speedo and odo now work, and I get all 4 gears.

Scanguage shows No codes, 2 not ready, so won’t know until I put on more miles.

Still don’t have cruise control (dash light won’t come on, none of the buttons appear to work). In fact the entire lower portion of the tach is dark (no lights at all, key on, nor on start). If anyone can please post a screenshot of what their dash looks like (preferably ‘98 or ‘99) that would be great!

I still cannot see the ABS light prove on key on, so am thinking maybe my instrument cluster has burnt traces or possibly has bulbs out? I found this in section 13-01-39 of the factory service manual. I guess I need to be ordering a gaggle of mini-bulb 13465.

Turns out I think I may have been thinking ahead and already bought some. I found these in my SHO pile of stuff to do to the car








I guess I need to bust out the screwdriver and pull the dash out to replace some bulbs.

 

[GEN 3 SHO FAN]

It will be surprising that all these bulbs wear out all at the same time... and its strange that your cruise stop working at the same time. (Related ?) Did you check the fuse for cruise ? You could try a cruise module from a salvage SLO (same part).

For instrument cluster lights, if you change them for led for the upper cluster part, think about to not put too high or too low beam led. And Im not sure they dimmable. You could be tired at night to look at them. (Most of them are too high in comparison of original bulbs but lower can be found, they are still higher than original ones).

For your problem, it could be useful to check these fuses under the dash :

 

[SLOWgod]

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

Random question about none of this. I was told to ask you. Are the abs modules the same for all years?

 

[Qshiplvr]

Random question about none of this. I was told to ask you. Are the abs modules the same for all years?

I cannot claim any knowledge for this paste from the original poster Gen 3 SHO lover above (post #24):

Also note that there were discussion that SHO ABS modules were differents between years too 96-97 vs 98-99.

Just to be sure, the number you need if you have to buy one is F8DC-2C346-BB, NOT F8CD-2C346-AB and new, they will have a yellow "SHO only" sticker (as your's).
(For others owners 1996-97 is F6DC-2C286-BA IIRC)

 

[SLOWgod]

Welp I got one from a 97 same years as mine just making sure hopefully it works

 

[Qshiplvr]

Welp I got one from a 97 same years as mine just making sure hopefully it works

If it doesn't work, you could send your original one here to be refurb: https://shoforum.com/threads/gen3-s...-also-eatc-instrument-cluster-refurbs.147605/

 

[SLOWgod]

If it doesn't work, you could send your original one here to be refurb: https://shoforum.com/threads/gen3-s...-also-eatc-instrument-cluster-refurbs.147605/

I think I’m going to send my old one forsure regardless maybe I’ll buy another one send it out too it just cost money hahaha

 

[Qshiplvr]

I think I’m going to send my old one forsure regardless maybe I’ll buy another one send it out too it just cost money hahaha

Just remember to follow the instructions I posted about how to order "off menu" - call them first