Played with my rear sensors a little today for science. At this point my sensors have been played with enough, that there is no telling what is right or wrong with them.
i have some thoughts on a more accurate approach at doing a sensor lift and also getting back to stock. I didn’t have time to fully vet out the thoughts, but the proof of concept worked out.
Ultimately my only goal today was to lower my rear end a little (I decided on 10mm). I think I can feel the horizontal left to right shimmy of my rear end because it’s lifted a bit. It’s not bad but I can feel it in the seat of my pants.
tools needed:
2 10mm wrenches
Either Techstream on a long cable or wireless, or OBD fusion with the AHC dashboard I shared earlier in this thread (I think, but definitely in the OBD Fusion thread). You need to be able to see the display while under the vehicle.
I put the truck on a somewhat flat surface and parked. Then did a N to L to N cycle and held the brakes a bit. At this point my height sensors were within 2mm of 0 Height registered.
i then turned AHC off and cut the ignition. OBD Fusion still reported sensor height after turning off the truck. The ECU was still working with ignition fully off for at least 30 seconds or so, but I put the car back in accessory mode just in case and it stayed on for 30 min or so while I messed with the sensors (I assume indefinitely until the battery dies).
I then climbed under the truck and loosened the US drivers side sensor. As an experiment I moved this sensor through its entire range in the bracket. The entire range was 30mm total (-13mm to 17mm). Then for giggles I disconnected the arm from the bracket to see what the total range was. My OBD Fusion dashboard has a range set to +-100mm and the sensor maxed out both directions. I didn’t bother reprogramming the widget to see what the ultimate range was. One interesting tidbit was that when you moved the sensor abruptly to an extreme the suspension stiffens up to max valving. Generally when just parked its sits in the middle at step 8, but it would switch to step 16 every time I would swing the sensor.
So here’s the fun part, it’s totally possible to move the sensor where you want based on the ECU height readings and lock the sensor down. I was able to lock the sensor down at 9.2 on driver and 9.5 on passenger, and I was in an uncomfortable position wedged under the truck. The theory is that if I lock down the sensor at about 10mm, when I turn AHC back on, because I’m in mode N (N=0) that the ECU will lower the truck 10mm and that will be my new N position. If you want to go up, swing the sensor to a negative number and the ECU will lift to get you back to 0. After getting the sensors set, I started the truck up, turned Ahc back on and waited for the magic. I thought it might adjust on its own and maybe would have if I waited long enough, ultimately I did a circle around the parking lot, it lowered almost immediately once I got going.
Interesting tidbit number 2. On my 2010, and I know at least some others, the rear passenger sensor is not a mirror of the drivers side. The bracket is very different with a smaller adjustable range and at a slightly different angle. Interestingly enough, the range of readings within this bracket was greater than the drivers side, even though the actual range of motion was smaller. Not really that important a fact unless you are blindly moving sensors like most of us have. This probably explains why a lot of Techstream screenshots of AHC lifted trucks show the passenger side 20-25mm higher. I suspect the passenger rear lifts/drops about twice as much based on how much the sensor is moved.
So the real fun part. Since all this is possible, you can easily jack your truck to whatever height you want it to be, then fiddle with the sensors until they say 0, and you are good to go. With that method, some care has to be taken with being on level ground. Alternatively, use the FSM to set the height based on the suspension components outlined and add or subtract whatever height, then set the sensors to 0, then you don’t even need to be concerned with level ground.
I didn’t bother measuring anything, I have no reason to believe that the truck didn’t lower the 10mm. On my short ride home I did feel like it made a difference, although entirely possible it was a placebo effect. I will say I did a N to L after, which my truck has trouble with, and it worked perfectly (although I only tested once so could have been a fluke).
The last piece to this puzzle, and I don’t know the answer is what the affect of the offset adjust is. Its function is to help calibrate the sensors if you follow the FSM plan with the Height offset utility. What I don’t know is when that value is added to the equation. The value can be between -20 and 20 mm, which is fairly significant. Does this value get factored in before Techstream shows you the height value or after. The question is, does the AHC ECU still target 0 and in the background it’s taking the value read from the sensor, adding the pad from the Height Offset Utility, and then displaying the height to you. Or is the target moved and if you have all your offset values set to 20mm, does that mean now that N=20. My guess is that it’s the former, But we kind of need to know one way or the other.
Either way, happy adjusting!
toyotaparts.ourismantoyotaofrichmond.com
. Guess that is proof that they do make a significant difference. If your truck is creeping up on 10 years, regardless of mileage, I'd totally recommend new globes!
forum.ih8mud.com
