New to forum. Just bought 2003LX - hope not a mistake. Have an AHC question already.

[tbuck]

Thanks, PADDO. I had hoped to have the new sensor by now but had minor issues with the Toyota dealer I found on line. I don't think it has yet shipped.

Assuming I can find the suspension control ECU (search shows maybe driver wheel well) .... how does one jump terminals on an ECU? Isn't it just a box with a multi pin plug port that is fed with a wiring harness?

Sounds like I may be better off waiting. I hate waiting.

 

[PADDO]

The AHC ecu is directly above the obd connector (dlc3 in LC/LX speak). You can fit a light gauge shorting jumper into the back of the connectors, they aren't sealed or anything. If you really wanted to do this as a temporary "battle override" you could also run a parallel cable from one sensor connector to its opposite and achieve the desired effect. Might be an option for the next guy with a screwed up sensor in the middle of nowhere.

 

[tbuck]

Interesting idea.
Not sure the best way to pull the signal from the left and send it to the right. Since the right sensor is trashed, I can cut the wire and use that connector/plug. Will need to study and see how to connect it to the output from good sensor for the signal. I don't think I want to cut the wiring on the good sensor for a splice. May be a fun project for the rainy weekend .... but I also have my backup ride (Miata) torn apart to replace the water pump and refurbish the embarrassingly noisy hydraulic lifters.

 

[tbuck]

So PADDO, I finally get the new sensor in today and get it installed. Crank up the truck, I can hear the AHC pump whining, L lite is lit - thinking things are good. No OFF light. Pump whines a bit more ... nothing. Push the button to move to N. Nothing. Still on the bumps. Pump stops whining, the OFF light begins blinking again.

Shut down and try again. Same results.

Pretty dang frustrating.

Any suggestions?

 

[aging fleet]

I can provide no help on things AHC, but it sucks you're having such an issue with the new ride. Hoping you can get it sorted soon and begin enjoying the truck.

 

[tbuck]

Update/closure on this problem ....
First - thanks to PADDO for the help with troubleshooting via numerous PMs.
Second - thanks to eliot for replying to my blind plea for help and selling me a pump he pulled from his truck.

The truck was riding on the bumps and the OFF light flashing. I had a single bad AHC height sensor (passenger) which I replaced that didn't fix the problem. I saw via techstream that I had zero pressure at any sensor.
Pulled and disassembled the pump (note: pump is held in one bolt in the engine bay and with 3 nuts you access in the wheel well). Nothing obvious. The pump would spin by hand. It's a simple gear pump and not really much that can go wrong with the pump itself. I've seen numerous threads about replacing a 'bad pump' which I would question.
I then checked the motor on the bench with a 12v power supply. It would hum, but would not turn. Symptomatic of a burned winding. Could certainly be the root of the problem so I began the search for used pump assembly vs. the costly new option. Also began sourcing parts to replace the AHC system as a parallel path.
After blindly contacting several forum members that noted they recently pulled their AHC system, I found a used pump.
Installed the new-to-me pump, put in the old fluid (for the time being) and the system came to life.

Next up will be to flush the system and optimize the settings.

 

[Junglejack]

AHC really is an excellent system and I am so glad to read that rather than just yanking it, you repaired it. All the same, no doubt not the introduction to an AHC equipped 100 you were hoping for. Do know, this is not a common occurrence and many now going on 18 year old AHC systems are still going strong.