kcdee00

Got a 96 4runner Limited and am having problems with the Speedometer....
I replaced the speedo (thought it was the problem) and now get the Check Engine Light (Previous owner pulled bulb on old one!!) ---pulled codes and said Speed Sensor....
The speedo works most of the time, but not always...When it doesn't, the ABS light comes on too.
In the searching I have done, there are speed sensors on each wheel, so I will check those first... Any other opinions???
BTW, The dealer I got it from said they replaced a Rear Wheel Bearing and seal... Could they have screwed the speed sensor up also? Thanks

kcdee00

nobody??

DeathCougar

iTrader: (23)

The speed sensors also act as ABS sensors. So, whichever one is defective, will also fix the ABS lights. First check the wiring, and make sure nothing is pinched or broken.

kcdee00

Ok, pulled the sensors, they look fine-they replaced the rear pass. side seal/bearing...my speedo doesn't work and the abs light is on (also check engine)-the code says speed sensor. How do you tell if one of these are bad? I will see if I can get the exact code from the ABS system and I will pull the axle back out to see if that is all put together right..Hope I find it, it kind of sucks not having a speedo....

97ltd4x4

Ok,here is the deal..Are you getting code P0500,vehical speed sensor malfunction code?If you are this is how it works:
applies to 5vz:

speed sensors->Abs ecu->combo meter->Ecm

so a speed sensor code throws both a ABS and ECM codes

so any speed sensor can cause this,next lets go to ABS:

Next we need to check ABS codes:
1 turn ignition switch "on"
2 disconnect short pin from DLC1(black test box on driver's side intake)
(remove little metal jumper)

3short pins,connect E1 and Tc(you can use a wire,a metal paper clip,not coated, works well)..you can see from the inside cover which pins are where.

4 read ABS codes:they will blink..something like this: /////// // is 72,/////// /// is 73........../=abs light "on"

There are 9 codes:
71,low output voltage right front speed sensor
72,..........................left front....................
73...........................right rear...................
74...........................left rear....................
75abnormal change in output voltage of right front speed sensor
76................................................ ..left front.....................
77................................................ ..right rear.....................
78................................................ ..left rear......................
79 deceleration sensor faulty code

71-74 is speed sensor malfunction itself,or installation problem(too close,not close enough to,sensor ring(tone ring),wheel with teeth)
75-78 is problem with rotor ie chipped teeth,not pressed in straight,wrong rotor,too many,not enough teeth.

You can do a couple of checks on the sensors themselvs.

front sensors: reristance check, 1.4-1.8 Kohm value
rear sensors:resistance check, 1.0- 1.4 Kohm value

Another check with a meter is a/c voltage,this is a true check(not found in the book)..disconnect sensor,connect meter to sensor pins,set meter to a/c volts and spinn the wheel...This is the actual signal that the ABS ECM will see(this is assuming the wiring is good)...your a/c voltage will get higher you spin the wheel..Or negative depending on how your test leads are connected...All you wat to see is the Voltage numbers getting higher + or - the faster you spin the wheel.

Hopefully you will find your problem doing these checks...

If it all checks good at the sensors,ohm and a/c voltage you need to have an EWD to compare those readings to the ABS ECM coresponding pin readings(possible wiring problem between sensor and ABS ecm)..do a really good visual check from the sensor to the ABS ECM harness.

If it all still test good,possible rotor problem,like chipped teeth,pressed on crooked,or wrong rotor.

To clear ABS codes:
1. keep short pin removed
2 keep E1 and Tc connected with wire
3 cycle ignition key..on..off....on
4 as fast as you can depress and release brake pedal......8times or more within 3 seconds.
5 normal code will flash...just blinks rapidly
6. remove E1-Tc wire,replace short pin

kcdee00

ok I will do that in the next couple of days...man all this electrical stuff is getting me....what happened to the good ole speedo cable like on my 88......Its just weird that this problem is so random...the speedo didnt work, then it does for a couple days, then when I think its gonna keep working, it quits out of nowhere....I dont even care about the ABS, i just want my speedo to work!! If I had to guess, I am thinking it has something to do with the abs rotor on the pass. side axle since the used car dealer I got it from said they replaced the bearing and seals on that side, but I will check it...

kcdee00

Ok, I tried to jumper these two, but now I am getting nothing from the ABS light. It doesnt come on at all when I turn the key now- not even for the check cycle- whether I have them Jumped or not>>> I will drive it a little today to see if it comes back on...Oh yeah, did I mention the speedo isnt working either (j/k)Thanks

kcdee00

now, the ABS light comes on, along with check engine like it has been doing.... its when i jump the two terminals, the ABS light just goes blank..GRRRRRRR

97ltd4x4

The speedo will not work if the combometer does not see the speedsensor inputs through the ABS ECU to the combometer:

For the ABS warning light circuit.Did you skip the part where you remove the little SHORT PIN in DLC1? I am not sure if the abs light will "light" unless you do this.

If you did and its still not blinking...from the book..it goes down a worm hole of testing....

tests for combometer,ABS control relay,harnesses between DLC1 and ABS relay.

There is a quick check for the Tc terminal circuit(circuit that puts ABS into"check mode":

Check voltage between Tc and E1 in DLC1,turn ignition "on" measure voltage between terminals Tc and E1 of DLC1: 10-14volts is good(source,battery voltage)

If its good,Possible ABS ECU defective...I have never hear of one going bad,so highly unlikey,but possible)

If not good voltage,need to check harness between Tc and ABS ecu...and E1 to ground(easy check,test OHM from E1 to battery neg terminal)

Also, can you clear codes and get Abs light to "blink rapidly"?

At some point you might just have to bring it into dealer

kcdee00

yes I am removing the pin.... The cruise and airbag lights flash repeatedly but I am getting nothing from the ABS light when I jump the two...As soon as I "unjump" them, it comes back on... The CEL code was for a speed sensor, but thats all the code reader I had could tell me.... I will do a few more things.... Definitely dont wanna take it to the dealer if I can do anything...It will probably be something simple, maybe not---my fingers are crossed..Thanks for all the help, if you got anything else, by all means...

kcdee00

ok, I know this is gonna sound crazy...I have not been able to get ABS codes from the stupid thing... I did a little more research and got kind of mad so I went and "lightly" tapped on the kick panel where the ABS ECU is and the dang thing must have reset, the ABS light started blinking repeatedly, and everything is back to normal----- for now... I will drive it a little more and take the kick panel off to make sure the plugs are all tight tomorrow--This is the craziest thing ever... I have "built" an older 4runner and Jeeps and this thing has been more of a PITA than anything---but I love it and have always wanted a newer 4runner..Thanks for the help and I hope this thread will at least help someone else diagnose their ABS or speed sensor system...