Speedometer/ABS Issues

[gretagreenbean]

Context: My 99 has never not had an ABS light on for the 3 years I have owned it. I have never experienced the throbbing brake pedal and so I ended up completely removing the ABS pump and tying everything together. Bled the brakes and have had zero issues.

However, when cruising at high speeds on washboard roads, my speedometer falls off at the dash. I stop completely, then start driving again and have speed readings again. This happens often and is annoying but not the end of the world.

Recently, I have noticed that there is a small rattle that occurs around the Driver rear wheel at low speeds. Im trying to understand if the ABS system in the rear and the speedometer are connected at all and if any of you have found a fix to the speedometer issue?

 

[phattyduck]

Recently, I have noticed that there is a small rattle that occurs around the Driver rear wheel at low speeds. Im trying to understand if the ABS system in the rear and the speedometer are connected at all and if any of you have found a fix to the speedometer issue?

Unless you converted your speedo to read from an (added) speed sensor on the output of the transfer case, the ABS computer is the source of the signal for the cluster, which then sends it to the ECU.

Does your ABS light exist at all? (PO removed the bulb?) You need to have at least two working wheel speed sensors for the ABS system to output a speed signal to the cluster. If you don't want that, you need to convert to an electronic speedo drive...

-Charlie

 

[JohnMc]

When my wife initially did the manual front hub conversion on her 4Runner, it disabled the ABS because the manual hubs didn't have ABS sensors. The speedometer gets it's speed reading from the ABS system, and with only the rear sensors sending signals, it acted more or less the same way. In some situations it would work normally, and sometimes, often at speed, it would drop to zero and stay that way until she stopped and started up again.

She did what phattyduck suggests - she added the Tacoma speed sensor on the transfer case and wired that up and the speedo worked normally again. (And later rebuilt the front hubs with the ABS tone rings and got ABS working again, but left the Tacoma speed sensor in place).

 

[vegask]

I ran mine with just 2 ABS sensors for awhile (I did a full float setup in the rear). And yeah, the speedo sometimes would just drop off and quit until I shut the truck off and fired it back up again.

Get the VSS for the tcase. Its 3 wires, power/gnd/signal, run that into the passenger kick panel. Get a dakota digital converter and remove the ABS computer and mount the dakota in its spot. The wire to control the speedo is available in that kick panel so its a pretty easy job to do.

 

[phattyduck]

I ran mine with just 2 ABS sensors for awhile (I did a full float setup in the rear). And yeah, the speedo sometimes would just drop off and quit until I shut the truck off and fired it back up again.

Get the VSS for the tcase. Its 3 wires, power/gnd/signal, run that into the passenger kick panel. Get a dakota digital converter and remove the ABS computer and mount the dakota in its spot. The wire to control the speedo is available in that kick panel so its a pretty easy job to do.

Adding the Dakota box is a good idea - then you don't have to futz with getting the right gear ratios for the speedo drive... just fix it digitally. I did that for my truck when I went from small to big tires (while keeping ABS).

-Charlie

 

[gretagreenbean]

Ill look into that. Thank you!