Hi -

Hoping someone can help troubleshoot my AHC (stuck in the hi position - truck was in my garage for a month as I was changing fluids, etc - drove it out and now won't return to normal position - led flashes when depress switch to change modes but nothing happens).
Others items:
Fluid is OE - not below min level
Fuses are good
Pulled rear sensor and drivers side sensor - both show increasing impedance as manually rotated - don't have shop manual to check impedance but the range/rate of change is consitant across both.
I haven't had a chance to pull and check the passenger side (the good folks of Slee Off Road said the rear is the first to go - but it apprears "consistant" with the drivers side)

Can anyone tell me what the impedances are for the sensors (maybe they are both bad - the ones I checked).
If the passenger side were bad, would it stick in the "hi" position?
Anything else I should check?

Closest L dealer (where I purchased the truck is 100 miles away) - really not thrilled about taking it out at hi way speed - really don't want to tow it.

Thanks for any advice!

Bill

 

easiest way for me to tell u. going to need a lexus scanner and go into what i call super enhanced mode and read the codes off that otherwise i dont know if there is a way to check it with out that scanner

 

... provide any impedance readings. The scanner reads off the height as measured by the sensor. It may be easier for you to consider the following two options.

1. Just get a new rear sensor and replace.
2. Open up the old one. The circular electronic part comes off the metal bracket, and then four screws will give you access to the innards. There are three gold plated spring loaded contacts. The problem is usually against the deeper end with corrosion. Meticulous cleaning will often make the sensor work properly. You may get increasing readings when rotating the sensor by hand, but when installed, the ECU will often get erratic readings and then get confused, raising the rear end sky high. Try troubleshooting the rear sensor first before the front ones.

What ever you do, new or cleaned old sensor, apply some dielectric grease to the sealing O-ring. This means opening up the new sensor too. Then, seal around the join with liquid electrical tape. This will prevent the same thnig happening again in the future.

 

...even though the impedance "appears" consistant there might be "hiccups" as the potentiometer is rotated. Additionally, it is your experience with properly maintained LXs as well that a bad sensor is usually the root cause? And to follow, the rear sensor is usually the culprit?

I will inspect the inards of the sensor again tonight - I did pull apart the rear - it was clean and dry inside and didn't show any signs of contamination - I did not check the "deep" portion of the spring contacts though. I did manually rotate the rear sensor by hand with the engine running (doors closed) to listen for the actuator kick in (had a jack stand in place to save my skull in case it DID actually work ) but observed no change.

One last follow up - do you know if I can potentially damage the system by driving it (asking in case I actually do have to head up to my DC dealer) - my concern is that I "think" I have heard the actuator pump come on for an instant but then stop (not entirely sure - when your trouble shooting stuff like this I swear you hear (or think you do anyway) all kinds of stuff ) and didn't want to risj further damage.

Regarding sensor cost - the best I'v gotten for the rear (89407-600010) is $269 - any ideas on who/where might/could do better?

Thanks so very much!

Bill

 

….I took a look at your previous posts and at the risk of being nosey…noticed you now drive a phaeton! Small world…I drive an 8! Once you get the 4WD “jones” it’s hard to quit!

Bill

ps: I really appreciate your help on my "lifted" LX - the Sewell boys said that's actually a plus down there in Texas...."ya might oughten want to keep it thata way".....

 

Well I hope I can be of some help here.

.... even though the impedance "appears" consistant there might be "hiccups" as the potentiometer is rotated.

Yes, that's what happened to my wife's LX, and also to my brother's LX.

... Additionally, it is your experience with properly maintained LXs as well that a bad sensor is usually the root cause? And to follow, the rear sensor is usually the culprit?

Yes, and yes, judging from the comments of the master tech who did the warranty repair.

... I did not check the "deep" portion of the spring contacts though.

That's where the problem was, at least in my case. Remove the springs, and check on the black contact in the deep end of the holes.

... Do you know if I can potentially damage the system by driving it (asking in case I actually do have to head up to my DC dealer) - my concern is that I "think" I have heard the actuator pump come on for an instant but then stop (not entirely sure - when your trouble shooting stuff like this I swear you hear (or think you do anyway) all kinds of stuff ) and didn't want to risj further damage.

To my knowledge, no there is no problem. Other than the fact that the truck's rear end is way up in the air (and in my case would go up and down at random - fun!), and that obviously at night the headlight aim is going to be way off, the actuators themselves will not be harmed by driving it around. Remeber, the ECU will stop adjusting the actuators once it "thinks" that that the suspension is at the correct height. The sensor just causes the erroneous setting.

.. Regarding sensor cost - the best I'v gotten for the rear (89407-600010) is $269 - any ideas on who/where might/could do better?

Holy smokes! I did not know that since mine was replaced under warranty. However, try Sewell Lexus or Irontoad as well. I am sure some of the other members here will have a better source for cheaper parts.

... Thanks so very much!


Not a problem! I hope you get the thing fixed soon.

 

....pulled the (third and final) sensor from the passenger side wheel arch - ohm meter indicated an open circuit regardless of potentimeter rotation. I opened it up and found it had been contaminated as one of the outer contacts had (as VCHENG had identified above) corroded within the "spring well". Cleaned it and replaced the spring with one modified from a ball point pen. Lubed and reassembled.

Works like a charm.

VCHENG, thanks for your advice and for having me stick with the plan to test all the sensors before moving on to other areas of the truck.

Bill

 

Well, thank you for the feedback. I am very happy that your truck is now fixed. This is the first time I have heard of a front sensor going bad, but basically the fault is internal corrosion, which is easily fixed. I think I will open up the front sensors and seal them better, just like the rear one, as a preventive measure.

 

nice. make me feel bad. fixing most problems i usually grab the scanner. compair what all sensors are reading and usually find an odd number. boom theres ur problem . i believe that u can diag 90% of problems though the scanner

 

....I just don't have the sensor required to ID the issue - but I should get one (being that I am so far away from a dealer). What is the p/n and is only one tool required to interface to each port or must I buy several sensors?

Thanks!

Bill