ABS vs AHC (1 Viewer)

[ProbablyTheGuy]

Ok so long story short, I finally got techstream working to see why my AHC isn't doing anything but blinking OFF in Neutral.

I do a health check because I'm an idiot and don't know what I'm doing but then get the following ABS/VSC/TRAC DTC codes:
C0278
C1223
C1224
C1241
C1268
C1340

I clear em to see what happens, turn the car on and then the height was set at Low and wouldn't move. I then restart the car and back to N.

Which one of these codes should I hunt down first, they all seem pretty related.

 

[ProbablyTheGuy]

Just checked #40 and 41fuse. Looks old and dark but not blown.

 

[suprarx7nut]

If you're interested in checking the AHC side of things, show us a screenshot of your data list page. Blinking AHC normally means a dead sensor or you're simply over-pressure. Easy fixes. The data list might reveal it.

When I ran a health check I got a couple codes the first time. They were related to VSC/ABS. I cleared them, checked again later and they weren't present. I think the health check can pull up ancient codes that haven't been cleared. In my case, they did not seem to be related to any current faults.

 

[ProbablyTheGuy]

If you're interested in checking the AHC side of things, show us a screenshot of your data list page. Blinking AHC normally means a dead sensor or you're simply over-pressure. Easy fixes. The data list might reveal it.

When I ran a health check I got a couple codes the first time. They were related to VSC/ABS. I cleared them, checked again later and they weren't present. I think the health check can pull up ancient codes that haven't been cleared. In my case, they did not seem to be related to any current faults.

That checks out, I can imagine noone has done much to this poor thing. Also why I got it for so cheap.

I'll pull the AHC stuff when I get home.

 

[ProbablyTheGuy]

If you're interested in checking the AHC side of things, show us a screenshot of your data list page. Blinking AHC normally means a dead sensor or you're simply over-pressure. Easy fixes. The data list might reveal it.

When I ran a health check I got a couple codes the first time. They were related to VSC/ABS. I cleared them, checked again later and they weren't present. I think the health check can pull up ancient codes that haven't been cleared. In my case, they did not seem to be related to any current faults.

Ok so, if I can get half of my front pressure to go to the rear we’d be great.

 

[suprarx7nut]

Ok so, if I can get half of my front pressure to go to the rear we’d be great.

View attachment 2651313

Haha, holy cow. Front sensors are weird too. Does the truck lean like crazy? Your sensors think you're 3" different side to side on the front. I suspect one of those sensors are bad. And probably drive torsion bar tweaking is in need as well.

 

[ProbablyTheGuy]

Haha, holy cow. Front sensors are weird too. Does the truck lean like crazy? Your sensors think you're 3" different side to side on the front. I suspect one of those sensors are bad. And probably drive torsion bar tweaking is in need as well.

Rear sensor and driver front are new. It leans in the rear towards the driver but only noticed when walking towards it while parked.

 

[suprarx7nut]

Rear sensor and driver front are new. It leans in the rear towards the driver but only noticed when walking towards it while parked.

If you haven't yet, time to adjust the zero point so that Techstream shows 0 when the truck is physically at the zero heights. It appears the fronts are currently out of agreement. Might be time for a new front sensor to complete the refreshed set of sensors if you can't adjust the bracket to correct that.

 

[ProbablyTheGuy]

If you haven't yet, time to adjust the zero point so that Techstream shows 0 when the truck is physically at the zero heights. It appears the fronts are currently out of agreement. Might be time for a new front sensor to complete the refreshed set of sensors if you can't adjust the bracket to correct that.

Ok I can get that going the heim joint on the passenger side is looking crusty and wiggles easily.
also to be noted, I’m told this thing has Land Cruiser Torsion Bars instead of the AHC.

 

[suprarx7nut]

Ok I can get that going the heim joint on the passenger side is looking crusty and wiggles easily.
also to be noted, I’m told this thing has Land Cruiser Torsion Bars instead of the AHC.

In that case, the crazy high pressure has me thinking there's a chance the bars (one or both) might be improperly indexed. Hard to say until you get the sensors reading accurately and check pressures. 3" of difference side to side would be comical so if it looks semi-even the sensor(s) are either improperly adjusted or dead.

 

[ProbablyTheGuy]

In that case, the crazy high pressure has me thinking there's a chance the bars (one or both) might be improperly indexed. Hard to say until you get the sensors reading accurately and check pressures. 3" of difference side to side would be comical so if it looks semi-even the sensor(s) are either improperly adjusted or dead.

When the front pumps up after start, it raises, drops, then raises again and I have a very comical Tennessee tilt going on like it wants to fit in with the diesel trucks. Thanks for helping and talking me through this.

 

[ProbablyTheGuy]

Front right ordered, I couldn’t get them close to 0. The front left was already adjusted all the way up.
Should I be concerned that the rear is not reading any pressure other than -0.2 yet?

 

[suprarx7nut]

Front right ordered, I couldn’t get them close to 0. The front left was already adjusted all the way up.
Should I be concerned that the rear is not reading any pressure other than -0.2 yet?

I wouldn't worry about the rear yet. Pressure is only measured at the outlet of the pump when the valve is directing fluid to the rear. You might not be getting past an earlier stage in the lift process since your sensors seem to be out of sorts.

Are you verifying the actual height of the car? Seen this yet?

AHC Info

Note: AHC services are now offered at the Air Down Gear Up shop in Frederick, CO. The owner of YotaMD, Andy, is also a co-owner of ADGU and happy to provide some of the common AHC-related tasks you may be interested in. See the link here for details...

www.yotamd.com

 

[ProbablyTheGuy]

I wouldn't worry about the rear yet. Pressure is only measured at the outlet of the pump when the valve is directing fluid to the rear. You might not be getting past an earlier stage in the lift process since your sensors seem to be out of sorts.

Are you verifying the actual height of the car? Seen this yet?

AHC Info

Note: AHC services are now offered at the Air Down Gear Up shop in Frederick, CO. The owner of YotaMD, Andy, is also a co-owner of ADGU and happy to provide some of the common AHC-related tasks you may be interested in. See the link here for details...

www.yotamd.com

I figured that was the case. Thank you.

I have seen it but since I cannot use my up or down buttons yet, I figured it wasn’t time to turn my reading comprehension switch yet on it. Plan on printing out some tomorrow.

 

[suprarx7nut]

I figured that was the case. Thank you.

I have seen it but since I cannot use my up or down buttons yet, I figured it wasn’t time to turn my reading comprehension switch yet on it. Plan on printing out some tomorrow.

I'm thinking step two on that cheat sheet is helpful right now while you get the sensors reporting zero when you're actually at the normal zero heights.

 

[LndXrsr]

New FR sensor is definitely your first step here. You'll probably get way different pressure readings once that's in. I bet the torsion bars will need some tightening still, and we'll see where your rear pressures fall, but the system is falling into fail-safe mode due to the wildly different sensor readings up front.

 

[ProbablyTheGuy]

New FR sensor is definitely your first step here. You'll probably get way different pressure readings once that's in. I bet the torsion bars will need some tightening still, and we'll see where your rear pressures fall, but the system is falling into fail-safe mode due to the wildly different sensor readings up front.

Thanks, yeah sensor is in the way. Should be here by the 27th. Will update after it’s on.

 

[ProbablyTheGuy]

Good news, sensor showed up today, I put it in and matched the physical height to the other side.

Still flashing off on the drive home. Plugged it into techstream and I have a C1711 code that wont go away on the clear. Gonna check the connection again.

 

[ProbablyTheGuy]

Ok I cleared it after unplugging and replugging.

No DTC's
FR Height Sensor -6.3
FL Height Sensor 0.1
RR Height Sensor 0.1
Front Pressure 5.1
Rear Pressure 4.4

I have no idea how toget the right sensor to read 6.3 inches higher than it is. Truck is not leaning that way at all.

 

[LndXrsr]

I'd check the wiring and plug beyond the sensor very closely to make sure there isn't an issue there. These things are just fancy resistors and any messed up wiring in the circuit could lead to false readings as well.