trying to help family by keeping this 4runner with 300K miles in service.
ABS error , the right front and rear sensor on the wheel show zero in Techstream when I drive
here is the snap shot of data from techstream below

found them both shipped from aliexpress for under 40$ the question is how involved is replacing them?

could it be just dirty? how do you clean them? the problem came about after changing tires .. so the tire shop did something I have to check but a quick pick I don't see any major issues

is it normal for these 2 sensors to read zero?
Zero Yaw Rate Sensor 0 deg/s
Master Cylinder Sensor 0.0 MPa


2002 4Runner 5VZ-FE




9/27/2021 1:32:50 PM

[ABS/VSC/TRAC Stored] System

[Parameter] [Value] [Unit]
ABS Motor Relay OFF
Solenoid Relay ON
High Hydraulic Boost SW OFF
Low Hydraulic Boost SW OFF
VSC/TRAC OFF SW OFF
Main Idle SW OFF
Stop Light SW OFF
FR Wheel ABS Control Before
FL Wheel ABS Control Before
RR Wheel ABS Control Before
RL Wheel ABS Control Before
FR Wheel Speed 0 MPH
FL Wheel Speed 17 MPH
RR Wheel Speed 0 MPH
RL Wheel Speed 17 MPH
Deceleration Sensor1 0.16 G
Deceleration Sensor2 0.02 G
IG VOLTAGE Normal
ABS Solenoid (SFRR) OFF
ABS Solenoid (SFRH) OFF
ABS Solenoid (SFLR) OFF
ABS Solenoid (SFLH) OFF
ABS Solenoid (SRRR) OFF
ABS Solenoid (SRRH) OFF
ABS Solenoid (SRLR) OFF
ABS Solenoid (SRLH) OFF
TRAC Solenoid (SMFR) OFF
TRAC Solenoid (SMFL) OFF
TRAC Solenoid (SMR) OFF
TRAC Solenoid (SPFR) OFF
Throttle Sensor 0 deg
Engine Speed 1062 rpm
Vehicle Speed 16 MPH
Yaw Rate Sensor 3 deg/s
Zero Yaw Rate Sensor 0 deg/s
Steering Angle Sensor 1150 deg
Master Cylinder Sensor 0.0 MPa
Test Mode Normal
Number of DTC 5







Parts
right front Toyota 8954235050
right rear toyota 8954535030

Attached Images

     

The wheel speed sensors are pretty easy to replace. 1 bolt holds each of them in then take a pair of slip joint pliers and twist/pull the sensors out. When you take the rear wheel speed sensor out spin the wheel if you can and look at the tone ring. If there is any oil on the tone ring then it's time to do rear axle seals and possibly rear wheel bearings.

I have no experience with those sensors. Sorry

I don't need to take the wheel off or anything else?
I can get it done by going under the car while the car on a ramp, no need for full on lift?

The rear wheel speed sensor can be done with the vehicle on the ground.

I'm not entirely sure about the front wheel speed sensor. You may need to remove the wheel and possibly the rotor to get to the wheel speed sensor bolt and clearance to pull it out.