Let me start by saying I love my AHC. I love the ride, I love the tune-ability and I like the up and down. 1999 LX470 with a little over 400,000 miles.
It’s broke and can’t fix it.
Now the backstory - we had a huge rainstorm and I am guessing the sunroof drains couldn’t handle the water (they were clear when I checked immediately after) and quite a bit of water came in down the driver A pillar and out of the dash about near the steering wheel.
Right after that, AHC OFF light blinks (car still running). I park the car, empty the floor mat, and dry what little water residue i see.
Next day get in the car and AHC OFF light is flashing. Hook up Techstream but can’t read codes, AHC defaulted to sport mode. Drove around like this for a couple months.
Cold weather lays in (Houston, TX) a couple days ago and AHC falls to low position. Dang it, now I have to fix it. With Thanksgiving holidays it gives me several days.
I break out the Techstream, Service manual and Electrical diagrams and get to work.
Checked fuses and replaced. Pulled relays and reinstalled.
B voltage starts at 12V but slowly drops to ~1-2V. Problem here.
I pull all three height sensors, ohm test them, clean them, retest, reinstall. They all check out.
Visibly check for leaks - nothing!
Disconnect every plug in the AHC system, spray with electrical contact cleaner, air gun dry, dielectric grease them, reconnect. There was no obvious damage.
After this, I got it to work for one day. While operating, i reset my torsion bars side to side and all numbers were all little high but but still in range (7.1). Accumulator was 10.1.
The next morning, went out, put it into High, Normal, then Low. When it went to low, AHC Off light started flashing again and I could not get it working again.
Following the Service Manual, using jumpers on DLC1, I could get codes 1731, 1732, 1733, 1734 and 1736.
Cleared Codes and got them all back except 1736.
Took the AHC switch apart and cleaned it.
Took the height sensors off again and retested them with a jig and 4.5V like the manual says. All tested fine.
Started testing continuity of the wires and all checked out.
I am guessing the AHC Control Module is fried.
I guess I could buy a used one off eBay and see if that works.
I have a used lift kit I bought a while back sitting in the corner that I can throw in if all else fails.
Any input or guidance from the AHC gurus out there?
It’s broke and can’t fix it.
Now the backstory - we had a huge rainstorm and I am guessing the sunroof drains couldn’t handle the water (they were clear when I checked immediately after) and quite a bit of water came in down the driver A pillar and out of the dash about near the steering wheel.
Right after that, AHC OFF light blinks (car still running). I park the car, empty the floor mat, and dry what little water residue i see.
Next day get in the car and AHC OFF light is flashing. Hook up Techstream but can’t read codes, AHC defaulted to sport mode. Drove around like this for a couple months.
Cold weather lays in (Houston, TX) a couple days ago and AHC falls to low position. Dang it, now I have to fix it. With Thanksgiving holidays it gives me several days.
I break out the Techstream, Service manual and Electrical diagrams and get to work.
Checked fuses and replaced. Pulled relays and reinstalled.
B voltage starts at 12V but slowly drops to ~1-2V. Problem here.
I pull all three height sensors, ohm test them, clean them, retest, reinstall. They all check out.
Visibly check for leaks - nothing!
Disconnect every plug in the AHC system, spray with electrical contact cleaner, air gun dry, dielectric grease them, reconnect. There was no obvious damage.
After this, I got it to work for one day. While operating, i reset my torsion bars side to side and all numbers were all little high but but still in range (7.1). Accumulator was 10.1.
The next morning, went out, put it into High, Normal, then Low. When it went to low, AHC Off light started flashing again and I could not get it working again.
Following the Service Manual, using jumpers on DLC1, I could get codes 1731, 1732, 1733, 1734 and 1736.
Cleared Codes and got them all back except 1736.
Took the AHC switch apart and cleaned it.
Took the height sensors off again and retested them with a jig and 4.5V like the manual says. All tested fine.
Started testing continuity of the wires and all checked out.
I am guessing the AHC Control Module is fried.
I guess I could buy a used one off eBay and see if that works.
I have a used lift kit I bought a while back sitting in the corner that I can throw in if all else fails.
Any input or guidance from the AHC gurus out there?