AHC rear sensor adjustment

[AtinLango]

The AHC rear sensor has a lever with 3 holes. I seem to see everyone using the bottom most hole (farthest from the sensor).

I am unable to use the bottom most hole due to some damage. Is it feasible / safe to use the middle (or even top hole)?

 

[IndroCruise]

The AHC rear sensor has a lever with 3 holes. I seem to see everyone using the bottom most hole (farthest from the sensor).

I am unable to use the bottom most hole due to some damage. Is it feasible / safe to use the middle (or even top hole)?

Suggest jack vehicle with at least LHS Rear wheel off the ground (full droop), then support with vehicle stand(s) at chassis rails for personal safety, then see what is possible under the vehicle by detaching the Sensor arm and re-attaching where you want it.

Then review very carefully -- can you be sure that the linkage will not go 'over centre' between up and down movements of the suspension and cause the linkage to close the wrong way around and damage the Sensor???

Even if that works safely, you may find that Sensor adjustment for "N" height is difficult or impossible.

It may be better to obtain a short piece of light steel, cut to length and drill holes at the the correct distance apart, then use this as a replacement.

 

[LJE]

I believe that using the wrong hole on the sensor arm will give you issues - thinking about how the linear (up/down) movement of the axle (well, really the body) gets translated into rotation of the potentiometer at the heart of the sensor, changing the "arm" length by using one of the other holes will throw the height change calculations of the system off.

This is because the same amount of linear motion of the body will now result in a greater amount of rotational motion at the potentiometer, making the AHC computer think that the vehicle height has changed more than it actually has.

 

[IndroCruise]

^^^^^
Strongly agree -- good if @AtinLango personally inspects under the vehicle to get a good understanding as mentioned in Post #2.

 

[AtinLango]

Suggest jack vehicle with at least LHS Rear wheel off the ground (full droop), then support with vehicle stand(s) at chassis rails for personal safety, then see what is possible under the vehicle by detaching the Sensor arm and re-attaching where you want it.

Then review very carefully -- can you be sure that the linkage will not go 'over centre' between up and down movements of the suspension and cause the linkage to close the wrong way around and damage the Sensor???

Even if that works safely, you may find that Sensor adjustment for "N" height is difficult or impossible.

It may be better to obtain a short piece of light steel, cut to length and drill holes at the the correct distance apart, then use this as a replacement.

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Thanks for the great insights.

 

[AtinLango]

I believe that using the wrong hole on the sensor arm will give you issues - thinking about how the linear (up/down) movement of the axle (well, really the body) gets translated into rotation of the potentiometer at the heart of the sensor, changing the "arm" length by using one of the other holes will throw the height change calculations of the system off.

This is because the same amount of linear motion of the body will now result in a greater amount of rotational motion at the potentiometer, making the AHC computer think that the vehicle height has changed more than it actually has.

Thanks very much. I appreciate.

 

[AtinLango]

Actually my problem started when i overloaded the boot one day. The rear end went down, but i managed to bring it back up (but it came higher than normal). Unfortunately from that time, the rear remained higher and quite unvomfortable to drive. By that time, the linkage had all along been attached to the bottom most (standard) lever hole.

I discovered through some testing that the rear comes back to standard height when i move the linkage to the middle hole. The car then rides very well, only trouble is that it drives only for a while and the lever flips over vertically, bottoming the rear.

The linkage side on the slider is at rock bottom. I cannot adjust it farther down. I believe if the lever could be adjusted over the splines at the shaft, that would have solved my problem right at the start by using the standard lever hole. But i opened it and there are no teeth to rotate over.

So that is the dilemma.

 

[AtinLango]

On a related note, there is a small screw hole on the upper part of the lever. It has a small pin (actually a screw). What is its use? Should i just remove the pin? It raised some interest.

 

[IndroCruise]

On a related note, there is a small screw hole on the upper part of the lever. It has a small pin (actually a screw). What is its use? Should i just remove the pin? It raised some interest.

If you mean the plastic holding pin which is found on new Front and Rear Sensors, go here for explanation:

Post in thread 'Did I just ruin my height sensor?'

Jul 6, 2025

I was looking to do some preventative maintenance and replace my front height sensors but I accidentally dropped my new sensor and broke that plastic tab that sits below the "L". I haven't tried to take off the old ones yet but looking at the rust, I'm gonna order some new mounting brackets before I try (any know part number?). If I can remove the old plastic pin from the old sensor, I may be able to just swap it on to the new one.

Any tips or advice?

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Here is one of my old posts explaining the purpose of the plastic tab and temporary...

• IndroCruise

• 

If you mean something else, please post a picture.

 

[AtinLango]

If you mean the plastic holding pin which is found on new Front and Rear Sensors, go here for explanation:

Post in thread 'Did I just ruin my height sensor?'

Jul 6, 2025

I was looking to do some preventative maintenance and replace my front height sensors but I accidentally dropped my new sensor and broke that plastic tab that sits below the "L". I haven't tried to take off the old ones yet but looking at the rust, I'm gonna order some new mounting brackets before I try (any know part number?). If I can remove the old plastic pin from the old sensor, I may be able to just swap it on to the new one.

Any tips or advice?

View attachment 3943240

View attachment 3943241

View attachment 3943243

Here is one of my old posts explaining the purpose of the plastic tab and temporary...

• IndroCruise

• 

If you mean something else, please post a picture.

Attached are pictures of the pin. I have failed to appreciate its use.

 

[IndroCruise]

Attached are pictures of the pin. I have failed to appreciate its use.

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If you look closely at the diagram (not the pictures) of the Rear Sensor attached to Post #2, you will see that the hole you have marked with a red arrow in your picture actually is the position of the temporary plastic post as described in Post #11. This also can be seen in the pics below.

For unknown reasons, your Rear Sensor incorrectly uses the link with the double-ended thread from a Front Sensor and not the correct fixed length link for a Rear Sensor. This incorrect link may be of the wrong length. As mentiond by @LJE, if the linkages are the wrong length, then the Sensor cannot work properly.

If the linkages have "flipped", the Sensor may have internal damage. Suggest remove the plastic cover (four screws) and inspect, clean and test the Sensor.

The Height Control Sensors are 'wear items'. If a Sensor is old or degraded, or causing erratic behaviours of the vehicle, then replacing the Sensor is the best solution AFTER first checking that the electrical connector and wiring harness are in good condition.

 

[AtinLango]

If you look closely at the diagram (not the pictures) of the Rear Sensor attached to Post #2, you will see that the hole you have marked with a red arrow in your picture actually is the position of the temporary plastic post as described in Post #11. This also can be seen in the pics below.

For unknown reasons, your Rear Sensor incorrectly uses the link with the double-ended thread from a Front Sensor and not the correct fixed length link for a Rear Sensor. This incorrect link may be of the wrong length. As mentiond by @LJE, if the linkages are the wrong length, then the Sensor cannot work properly.

If the linkages have "flipped", the Sensor may have internal damage. Suggest remove the plastic cover (four screws) and inspect, clean and test the Sensor.

The Height Control Sensors are 'wear items'. If a Sensor is old or degraded, or causing erratic behaviours of the vehicle, then replacing the Sensor is the best solution AFTER first checking that the connector and wiring harness are in good condition.

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The rear linkage is the adjustable type. It was replaced by the technician who used to work on my AHC after he changed the struts. I have the original one intact.

I am trying to see how to order for the one in the second picture you shared above.

 

[IndroCruise]

The rear linkage is the adjustable type. It was replaced by the technician who used to work on my AHC after he changed the struts. I have the original one intact.

I am trying to see how to order for the one in the second picture you shared above.

There are cheap substitutes but based on feedback on IH8MUD over the years, recommend buying only genuine Toyota/Lexus OEM Height Control Sensors -- more expensive but better for reliability and longevity and to avoid disappointment. Impex (Japan), Partsouq (UAE), Megazip (Singapore), Amayama (Japan) have stocks -- various prices, suggest compare with local Toyota/Lexus Dealer price in Uganda. As mentioned previously, first check that the Height Control Sensor electrical circuits (meaning electrical connectors and electrical wiring harness) are in good condition.