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2014 Prius ABS Question

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Rickinohio, Dec 23, 2023.

  1. Rickinohio

    Rickinohio Junior Member

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    ABS, VSC, TRAC lights on. C1466 code present, doesn't clear. Wires & connectors that can be seen by the right rear hub clean with no obvious signs of damage. My scan tool can only read and clear the ABS codes and is not capable of reading the actual speed sensor signals. I understand that the most likely suspect is the wheel speed sensor(~$300!!) itself but I’d like to confirm that by swapping the left & right side wires (or connectors) to see if the problem transfers to the left side. Swapping hubs (sensors) is an awful lot of work for me (physical limitations) and running jumpers from side to side isn’t practical either at the sensors themselves given the cramped area where the sensor side of the connectors are. Looking at the dealer’s parts diagrams, it appears that there are rather short (3 - 6 feet?) harnesses for both the left & right rear wheel speed sensors. I’m thinking these two harnesses appear to come together somewhere in the rear of the car and it might be as simple as swapping the two connectors at that junction point. Or, I’d be able to rig up some jumpers if it’s more accessible there than at the hubs. Has anybody done this, or know where these two harnesses lead to, or have a harness routing diagram showing the physical routing of these two harnesses? Thanks in advance.
     
  2. Tombukt2

    Tombukt2 Senior Member

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    My TRQ rear hubs with The sensor is built in like the originals are only like $95 a pair and I've logged a buttload of miles on one set and I've had no problems so I'm not paying the $288 from Toyota or whatever's going on here lately haven't seen that being needed yet and took me about 45 minutes aside to change them I can do the fronts faster but anyway I have some physical limitations but they're not serious yet I'm almost 70. What happens if you unplug the wheel speed sensor and run the test again what codes do you have now with it unplugged Do the same to the other side and see if you get similar I mean personally to be honest about it if there's no rubs on the harness and it passes through the body grommet and goes up into the channel like it's supposed to I would hate to think that low of voltage of wiring would be any kind of damage just by sitting there sending a signal back and forth or whatever it does But then again I guess anything is possible All the ones I have changed the harnesses have been noticeably damaged ripped out skinned until bare copper showing. Good luck
     
  3. Rickinohio

    Rickinohio Junior Member

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    UPDATE: I traced the wiring harness down and the connectors can be accessed behind the side trim panels just behind the rear seats. I was able to disconnect both the left and right wheel speed sensors at those points. Next I ran two jumper wires from the right connector from the ECU (or wherever it comes from) to the connector going to the LH wheel sensor. The C1466 was able to be cleared and a C1467 code then showed up. I had previously read 13.78 Vdc at the connector at the RH wheel sensor (disconnected from sensor) proving that the all the cables to the sensor were probably good. With the C1467 (LH wheel speed sensor code) now showing up I was able to pretty much definitively conclude that the right hand wheel speed sensor must be bad (and not other harness wiring or any upstream electronics). I bit the bullet and ordered a new hub assembly.

    I also took some readings from the LH rear wheel speed sensor: 13.08 Vdc and 12.25 Vdc. The two different readings come from when the sensor is either on or off a "tooth" on the tone ring and were taken when the the wheel was motionless (a 'scope wasn't used). I'm assuming these are the proper signals since no DTC codes are given for that wheel. Contrast this with the defective wheel which read a constant 13.78 Vdc whether on or off a tooth.

    I also ran ran across a very helpful YT video for disconnecting that $*^%$$#!! connector at the hub:

    .

    This guy did a really great job showing how to get that bugger off.
     
    Mendel Leisk likes this.
  4. Tombukt2

    Tombukt2 Senior Member

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    Upon reassembly you some break grease on the male part of the outside of the gray connector when you put it together makes a huge difference getting it apart and I do the same thing I just use long angled needle nose I have 45 and 90 makes a huge difference on doing lots of different plugs.
     
  5. Rickinohio

    Rickinohio Junior Member

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    Great idea Tom, thanks! Funny you should mention that about the 90 degree pliers, I was looking for mine just for this purpose but heck if I could find it.