First issue with my truck, any ideas what's wrong?

[George718]

Some months ago I noticed that sometimes, just sometimes, the shifter would be harder than usual to move on my 2018 with 56k miles. Resistance was present when shifting throughout the PRND gear range; it felt "sticky".

Fast forward to last weekend: Cold and wet morning. I took a short trip to the grocery store. After starting the motor to get ready to head home, I was greeted by the following lights on the dash:

(1) Check-engine
(2) TRAC OFF
(3) 4 LO (this one was blinking)

After getting home I pulled the codes:

• OBD2
  • P0705
    • Transmission Range Sensor “A” Circuit (PRNDL Input)
• ABS
  • U0073
    • Control Module Communication Bus “A” Off
  • U0100
    • Lost Communication With ECM/PCM “A”
  • U0114
    • Lost Communication With Four-Wheel Drive Clutch Control Module
  • U0123
    • Lost Communication With Yaw Rate Sensor Module
  • U0124
    • Lost Communication With Lateral Acceleration Sensor Module
  • U0126
    • Lost Communication With Steering Angle Sensor Module

I found this thread and decided to, as a first step, replace the Neutral Safety Switch.

This thread was really useful, thank you to everyone that contributed. In addition, I also found the following threads and youtube videos useful:

https://www.toyota-4runner.org/threads/nss-range-selector-switch-p0705-code.285833
https://www.toyota-4runner.org/thre...ad-neutral-sensor-switch.236120/#post-3737885

Video 1
Video 2
Video 3
Video 4

• my equipment
  • new neutral safety sensor: Toyota part number 84540-35061
  • ramps
  • two pry bars
    • one big one, one smaller one
  • vise grip
  • propane torch
  • mini sledge
  • 22mm open-ended wrench to remove o2 sensor
  • will need light if working after dark
• my procedure
  • front wheels on ramps
  • used penetrating oil, but wonder if this can be skipped next time; not sure it provides a benefit.
  • disconnect power plug
  • remove o2 sensor and move out of the way
  • remove nut and bolt securing the neutral safety sensor
  • use a cold chisel and mini metal sledge to knock off the four metal arms holding the sensor to the shaft. it was helpful to start with the transmission in P, then shift the transmission into D to make it easier to get a good angle when knocking off the metal arms with the chisel
  • sand the shaft smooth
  • simultaneously use two pry bars to remove the sensor’s body. did not need heat to do this.
    • big pry bar from the left
    • small pry bar from the top-top-right
  • now for the metal part of the sensor which has fused to the transmission shaft
    • note: tried using a dremel to cut notches and chisel or pop off with a screwdriver. did not work.
    • note: tried using a puller. did not work.
    • used a small propane torch to heat the sensor’s metal piece. DO NOT LAY UNDERNEATH AS IF YOU OVERDO IT, HOT MOLTEN METAL MIGHT DRIP DOWN ON YOU.
    • grab the metal cylinder with vise grip and pull
      • have also seen it get pried off, but this did not work for me
  • sand the shaft smooth
  • i dabbed a bit of dielectric grease inside electric connector. might skip this part next time, there was none from the factory and no evidence of corrosion.
  • anti-seize the shaft
  • mount new sensor
    • grab a small piece of wood, place it against the sensor, and hammer on the wood to push the sensor back into the correct position on the shaft
    • nut 5 ft/lb
    • bolt with a dab of anti-seize, 7 ft/lb
  • put o2 sensor back
    • small amount of anti-seize
      • ensure anti-seize you’re using is safe for o2 sensors
    • 32 ft/lb
  • ensure you can start the motor in P and N
  • you’re done

I would have preferred to not use heat given there's a seal on the transmission side of the shaft, but resorted to it as I couldn't break the old sensor's metal metal portion loose in any other fashion. As others have said the old sensor's metal part seizes to the shaft.

Good luck.. and if anyone has a good idea for doing this job without heat, please test it out and report back. I hope to keep the 4runner for a good long while, and the way we salt our roads in PA it's only a matter of time until I'm forced to repeat this job.. would love to be able to do it without risking damage to the transmission seals.

Photos: https://photos.app.goo.gl/H4ATUTiXwE4Xdw1S8

 

[fourwd1]

Nice write-up !