Need help with wheel speed sensors

I agree with you 100%. But I have already changed the passenger rear sensor and also the ABS rear harness. Reset the code but it came back. Granted that it could still mean that the wire from the ECU to the rear harness can the culprit but the again, from ohm reading it's less likely. By no means I am trying to convince that it is a wheel bearing issue and that's why I am holding off the bearing swap but it's interesting that some others faced the same exact issue and got it fixed after wheel bearing swap.

Anyway I guess I'll update on my side after I do the connectivity check from S1 to S22.

 

Btw really really appreciate posting the PDF. I had some previous versions but this one seems to drill even more specially the rear ABS harness as well. Thank you so much!

 

Also check voltage between Connector S22 Pin 4 (Yellow) and a known good ground with the key on, it should be battery voltage.

Also might check Connector EB2 in the engine bay.

 

We replaced the wheel bearing. Basically had 2 drivers side wheel bearings. we didn’t think it would matter and less things to worry about for spares but after replacing the wiring and sensor replacing the wheel bearing did the trick.

 

I checked the wirings today and here's what I see:

S1-5 RR+ to Xa1-2 RR+: Continuity is good
S1-19 RR- to Xa1-1 RR-: Continuity is good

S1-20 RL+ to Xa2-2 RL+: Continuity is good
S1-6 RL- to Xa2-1 RL-: Continuity is good





Next I turned the ignition to ON (but not start the engine) and confirmed that Xa1-2 RR+ to Battery GND and also Xa2-2 RR+ to Battery GND both are 12.x volts. Previously I checked the resistance between Xa1 - 1 and 2 and also Xa1 - 1 and 2 with the S1 connected to the Skid control ECU and both had 150k ohms telling me that they are still connected to the main board inside the ECU. Note that my issue is C1407 i.e the Rear passenger sensor but for the sake of comparison I got the numbers for both rear passenger and rear driver to make sure all the readings are correct.

So S22-4 connects to Xa1-2 and I have confirmed above that it's 12.x volts with the ignition ON.

I didn't have time to check this. So maybe I will give it a shot over the weekend.

So now that I am at square one, I went back and read the service manual again for C1407. Looks like all the connectivity and voltage check is done at step 4 - 6 which seems to be fine in my case. But Step 1 - 3 seems to be checking data on Techstream for "momentary interruption". Is there any other way to do this check without a Techstream. As a starter I don't have a Techstream, I know that I can get a bootleg version from Amazon but everywhere it says I need to use a burner laptop to use the bootleg version.

Secondly, at the very top of C1407 diagnosis, it mentions that one reason for this DTC trigger is an actual open/short in the sensor for 0.5 seconds but the other reason is "With the IG1 terminal voltage at 9.5 V or higher, the sensor power supply voltage decreases for 0.5 seconds or more". Anyone knows if there's any way to check the latter without a Techstream?

 

Any scan tool that can read data from the ABS Module should be able to view those PIDs, you don't necessarily need Techstream.

 

My bad for this dumb question but do you mind explaining what you mean by "should be able to view those PIDs"? Meaning I know that scan tools can read each sensor's speed data real time, is that what you mean?

Btw this is the specific diag step (i.e step 1) that I am talking about. I know that Step 2 is reading speed sensor and Step 3 is clearing DTC and re-check again can be done with a scan tool so no issues there. I just to double check that you are saying I can do the below step 1 on a scan tool too, right?

 

Yes those 2 parameters (PIDs) are in the data list so a scan tool that can read ABS data should be able to access them.
The file below shows every data parameter and bi-directional control available for the ABS.

 

Update!

So while I was waiting for the weekend to do the testing, happens to be that I found out a Toyota mechanic who said he can check the truck out at his dealership. So I took the truck to him on Wednesday and mind you that I have new rear harness and new rear passenger speed sensor (both OEM) installed on the truck already. He calls me back on Thursday afternoon saying that he replaced (the already new) rear passenger speed sensor and now everything is resolved?!?!?! Anyway I go pick up the truck and yepp he wasn't lying. Anyway I drive for an hour and half back home and the moment I take the exit I drive over some road debris and bam the ABS lights come back on again! I call him and he said most likely there's terminal contact issue and he can take a look at it on Saturday. So today I go out to get gas and to my surprise the ABS light is gone! I drove for about an hour, drove over every single pothole that I know of, drove on the freeway shoulder on the dirt, jumped the curbs but nope nothing. Dash is clean and no ABS lights. In any case I am still going to take the truck to him tomorrow to do a check but for now this is promising. Now that I think about it, I think the whole issue was contact problem but what doesn't make sense in all this drama is that how come clearing the code didn't help and it would come back right after!

For anyone who is reading this in future, if you are in San Francisco Bay Area and having issues with dealerships not looking at your truck properly because it's lifted, take it to Santa Cruz Toyota. Even better, DM me and I will give you the contact of the mechanic who does the lift at the dealership and he can do the diagnosis of your lifted truck. He wasn't comfortable with me posting his name on a public forum and hence I am not mentioning it here.

 

Update

Saturday morning I start the truck, no ABS lights or whatsoever. I drive for like 5 mins, go over the train tracks and bam the lights come back on again! Anyway I take it to the dealership and they re-opened the RO order and took a look at it. The mechanic called me and told me that apparently when they pulled the truck to the service bay there was no lights and the dash was clean. He asked me if he could take the truck to his home and drive it more to see if he can bring the lights back on. I said yes and thankfully that helped. The next day he called me and said he was able to get the ABS lights on again and it happens when the rear wheel gets a hit from a pothole or something. So he drained the rear diff, pulled the axle and confirmed that the wheel bearing looks worn out. After replacing the wheel bearing, I drove it for about 100 miles and so far no issues. He told me he will keep the RO open for another week to get a final confirmation that the ABS lights is gone for good. If not, he asked me to bring the truck back and he will talk to the Toyota engineers at that point. Meanwhile I am going to take the truck over the weekend to the Eastern Sierra in Northern California and possibly try to see if I can get some desert running and rock crawling in to really really test it out. But so far I am hopeful that this time the issue might have been fixed for good!

 

Off topic (sorry) but nice truck.