Height control sensor (1 Viewer)

[ticoman]

I have been doing my annual AHC maintenance and have run into an issue with my right front height control sensor. It all seems to run fine, but when I hook up Techstream and try to adjust that sensor it will only show -26-0 on the whole movement of the slide. no positive numbers at all. Does this mean it is faulty? Thanks for your input

 

[ticoman]

Does no one have any idea if this unit is faulty?

 

[IndroCruise]

I have been doing my annual AHC maintenance and have run into an issue with my right front height control sensor. It all seems to run fine, but when I hook up Techstream and try to adjust that sensor it will only show -26-0 on the whole movement of the slide. no positive numbers at all. Does this mean it is faulty? Thanks for your input

** Late edit: Detail of Diagnostic Trouble Codes (DTC's) for Height Control Sensors - Extract from FSM

Unclear what Techstream is measuring here?? Inches, millimetres, volts, ohms??

Whatever, how does RHS Front Sensor compare with LHS Front Sensor and Rear Sensor??

Assume Front 'cross-level' has been checked -- no inconsistencies with Right and Left tape-measured physical hub-to-fender measurements??

Suggest remove the Sensor, break out the multimeter and test smoothly changing output voltages with 3 x 1.5v batteries in circuit per FSM, as attached below.

Also suggest dismantle Sensor and inspect internally.

Or, use the @PADDO method to measure smoothly changing resistance (ohms) as described at this post:

High as a kite, hard as a rock! (Yes AHC again...) - https://forum.ih8mud.com/threads/high-as-a-kite-hard-as-a-rock-yes-ahc-again.1119157/#post-12149330

Also suggest be aware that the DIAGNOSTIC system has limitations. For example, the presence of any of the Height Control Sensor DTC's indicates a definite fault -- but the reverse is not true. Absence of any of the Height Control Sensor DTC's DOES NOT provide assurance that the Height Control Sensors are healthy -- it simply indicates that the Sensor output voltage is within the acceptable range of 0.3 volts to 4.7 volts per FSM extract below and attached, but does not tell whether the output is correct for the physical height position. If due to wear and tear, corrosion or whatever, a degraded Sensor sends a wrong signal for the actual height of the vehicle but still within the FSM-specified voltage range, then there will be very strange height behaviours by the vehicle. The ECU tries to cause the vehicle height to be matched to the bogus signal -- but there may be no DTC. In such circumstances, it is the vehicle behaviour, not Techstream, which reveals a Sensor fault requiring investigation.

This is also described in various other posts on IH8MUD -- for example Post #76 here:

Impex is LEGIT 4 new AHC globes. Door To Door from Japan, less than 2 weeks - https://forum.ih8mud.com/threads/impex-is-legit-4-new-ahc-globes-door-to-door-from-japan-less-than-2-weeks.1256544/page-4#post-14001281

And at Post #15 here:

Intro and yet another AHC thread… - https://forum.ih8mud.com/threads/intro-and-yet-another-ahc-thread.1281317/#post-14403443

And with more pictures at Post #932 here:

Definitive list of AHC maintenance items - https://forum.ih8mud.com/threads/definitive-list-of-ahc-maintenance-items.604577/page-47#post-14378858

Unless there is some cause of 'lean' of the vehicle, or unless the Sensors require adjustment, or unless there is one or more faulty Sensors, then the Height Control Sensor readings on Techstream screenshots should be close to zero with differences within +/- 0.2 inch or +/- 5 mm.

Bottom line: On a 2006 vehicle, the Height Control Sensors are now ~17 years old -- they are 'wear items'. If the carbon track is not showing signs of wear (reduced thickness, changed resistance, changed voltage outputs at wear point), and/or reduced brush pressure (weak contact, variable effects on voltage output), and/or the beginnings of corrosion or 'tracking paths' inside the Sensor, these wear conditions will arrive sooner than later.

Suggest cut to the chase and replace:

Toyota/Lexus Height Control Sensors – Part Numbers:
89405-60012 (Front Right)
89406-60022 (Front Left)
89407-60010 (Rear)

Or consider AISIN Sensors -- because AISIN are suppliers to Toyota/Lexus:

Aisin Height Control Sensors – Part Numbers:
HST-020 (Front Right)
HST-021 (Front Left)
HST-026 (Rear)

Suggest avoid the unhappiness which seems to arrive with other short-life substitutes and fakes.