Started working on my three yellow lights.I had my ABS codes read. Code 91 left front sensor output low and code 119 left front sensor output intermittent. I measured the resistance at the plug on left front inner fender. It measured 1042 ohms right in the middle for a good sensor reading. I then jacked up the left front wheel and spun it with my hand and I got about .5 volts AC. Code 91 said low sensor output. I could not find anything in the RAV about what good test results should be. Any body know?

 

Just replace the hub, along with the mounted sensor. Not a difficult or expensive job.
If you really wanted to check the voltage, you could try comparing to another wheel.

 

I agree with just replacing whole hub. If bearings are bad it can cause sensor issues with weight on wheels. Might be worth it to replace sensor connectors with something else or just hard wire them as well. They basically disintegrate after a while from the heat under the hood.

I replaced both front hubs recently with some cheap units (bout $60 each) that include sensors and confirmed with an ABS scanner that they both function properly. Can't speak to their longevity, but I've read around that people have used the cheap hubs with no problems.

 

I hope your cheap hubs last longer than the cheap hubs that I installed on my Dakota, which only lasted about 50,000km

 

I compared left and right front sensor voltage and indeed the left front one read .13 volts and the right read .18 volts when I spun the wheel hand over hand, probably 5 mph. I did all the tests on the ABS system as per British Atlantic. The shuttle valve also showed as bad. I changed out the left wheel sensor and the shuttle valve. Had the ABS codes removed and took for a drive. Two of the three Amigo light stayed on. Shut off the engine for 10 minutes started it up and the other two Amigo lights were off. I drove it 25 miles at highway speed and the three lights staid off. There really is hope. Thank you everyone for your help and sharing your knowledge.

 

Well I am back. Drove the Disco II 50 miles yesterday and the three Amigos came on and then the check engine light. The ABS code was 119 left front sensor low output came back and the code 306 came back. Code 306 is misfire on number 6 cylinder. I have been chasing this code. I have replaced the coils, the plug wires, exchanged new spark plugs, measured resistance in injectors and exchanged them, inspected all injector connections and measured the injector wires for continuity and resistance. Number six cylinder has good compression. I have also been chasing this code 119 also. I changed out left front sensor and ran the sensor wire all the way to the plug-in at the SLAB box. I replaced the shuttle valve and did the ground modification. I inspected the left front wheel bearing and the wheel that the sensor works off of, all looked good. Where do I go next? Some one on this forum mentioned about changing out the ECU. Do they go bad? Can these problems get created in the ECU? What do you think?

 

Ok back to brake problems. I have had the brake code for for low output on left front wheel. I replaced the sensor with the 144 inch wire that goes all the way to the ECM from Atlantic British, this eliminates the potential connector problems. Drove it still had all three yellow light problems. I had all the ABS brake codes removed. Going by advise I changed the wheel hubs out (180K miles on them) and took it for a drive today. At about 12 mph left front brake applies and ATC yellow light comes on. When I take my foot off the gas the brake releases and the yellow light goes off. I backed up 100 yd to "unconfuse" it and tried it several more times going forward same result. I went around and felt all 4 brake rotors and the left front was way warmer than the other three.

From what it appears to me is the computer is getting a signal that my left front wheel is spinning so it is applying the brake to slow it down. The only thing I changed is the wheel hubs on both sides. I did not change any sensors or connections.

Where do I go from here?

 

Well that is interesting. The sensor puts out a sine wave signal based on the square tooth reluctor on the wheel hub. All the sensor does is read the reluctor teeth. You may need to ask The Deputy if he has seen anything like this but the only thing I can think of is the reluctor teeth are incorrect on the new hub.

 

I have measured the voltage with the old wheel hubs by spinning the wheels by hand. I could do that same exercise again with the new hubs and compare the results. When I first did the spin the left sensor only made ½ the voltage of the right. After I changed the left sensor the readings were nearly equal. I never thought about counting the teeth on each hub, but it may come to that. I have to drop the drive shaft .Thank you for your thoughtful advise.

 

Yeah, anytime l have a drastic change in behavior from a changed/replaced component...my first thought is a 1) incorrect or 2) damaged or 3) poorly manufactured part or 4) l f'd something up (yes, there's always that possibility...lol). Very, very strange that the wheel sensor would indicate "wheel spin" to the WABCO ABS/TC unit, especially at that speed? Weird one for-sure. Even if the wheel sensor was a different style or something, you'd think you'd get an erratic signal code or loss on reading or something...not a "wheel is starting to spin" message.

Me, l guess l'd go back to the hub and check sensor ends to be sure they are exactly the same (new hub sensor and one you installed earlier).