On the hook. **Fixed**

remember5

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Well for the first time since I've owned Lord Buckingham he dropped to the gunwails and was undriveable. Had to call a roll back to bring him home. Very sad as I was just celebrating about a year of no problems other than the check engine light. More to come...
 

remember5

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Well this has got to be electrical, codes are C1A72, 74, 75 and U0421. As soon as I reset the code the compressor starts and in maybe 4 seconds the code returns and the compressor kicks off. I swapped the relay and all fuses are ok. Jumped the compressor relay and it ran for several minutes but never lifted the truck. Galley pressure was over 200 but all valves were at 0 which makes sense since it's sitting on the bumpstops. I previously got the yellow suspension light maybe twice over 200 miles driven and it reset with a cycle of the ignition switch.
 

Houm_WA

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You towed for THAT? Do you not have a GAP tool? Seems like you do since you have codes. Why not put it in BUILD MODE or otherwise reset codes and pull fuses; then drive home.....?
 

remember5

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I had the Nanocom with me but as soon as I clear the code it comes back. It will not inflate at all. Even jumping the relay and letting the compressor run it will not lift up. I messed with it in the rain yesterday a bit but won't really dive in until it's decent outside. The codes indicate a wire or connection failure since it calls out 3 of the 4 height sensors.
 

Houm_WA

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Interesting....even with the wire bundle ripped down off the frame, my EAS was functioning. It could be that you were are too far out of range. You may want to jack up the truck manually to the extent possible and then try firing up the compressor. THEN pull the dang fuses. You'll want to then check your wires and your brackets that hold the height sensors. If one of them bent, the calibration can go wonky. How old is your compressor?
 

remember5

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Jacking the truck manually was a recommendation on the FB forum to another guy with the same issue, I don't understand the reasoning for that. I do have lift rods but have had them for years. My compressor is probably original but rebuilt two years ago. I haven't been offroad in a year so nothing should have bent. I don't understand why jumping the compressor didn't build pressure to lift it up unless the valve is stuck open and still not sure about that.
 

Houm_WA

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Yeah man, I don't know. I'm just going off your symptoms. I just know that one time I had an issue where the vehicle wouldn't raise, and it was because the EAS was so far out of range that the settings just didn't register with the ECU; that's the reasoning behind jacking it up manually, then the sensor readings are withing range and the compressor will take over.

Then, you have to figure out why it happened in the first place. For me, it was the whole bent sensor bracket, but also...one of my airsprings was worn out. That doesn't mean it wouldn't hold air, but it was shot and probably affecting things too. I snapped a swaybar end link, too. All in the same day! I was off-road. It was kind of a miracle that I pulled fuses and crept out of the forest.

After that, I had the shock replaced....the dealer couldn't calibrate it (because it was too far out of range) and I ended up doing an iterative calibration myself with the help of the fine customer support folks at GAP. That was good for a while, but indeed that bent bracket (which went undetected at the time despite the GAP people suggesting I look into that possibility) led to problems a year or so later. New compressor (it was probably due anyway) and then finally after some cross-articulation errors we dug into the EAS and found that the bracket was bent; sorted that out, and it took a calibration with ease. Been good ever since.

A lot of what you read on these message boards comes from two sources:

1. Knowledge of how the system or vehicle is designed or otherwise functions.
2. Just experience of the "that happened to me once" variety.

Both are helpful.
 

remember5

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So the Nanocom is reporting the compresser exhaust valve is 100% open which is why it won't lift up. I think I can test it with a multi meter but will need to read up on that. And the pressure sensor too. Glad I have another daily driver...
 

remember5

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Today I jacked him up so I could get under to the compressor and once on jack stands my warning went from red to amber. Still wouldn't inflate so I took the cover off the compressor and was checking for voltage at the compressor and unplugged the main power plug and wasn't getting 12v, jumped the relay again and reset the codes and realized I had the stupid fuse in the wrong slot, moved it and then tried again and still got the amber light. Unplugged what I think is the valve plug and plugged it back in, cleared the codes again banged on the compressor and valves with a screwdriver and put it in offroad height and it lifted up. Pulled the jack stands out and went down to regular height down to entry height and back up without issue. However, I'm getting a info message the the suspension is rising slowly. The compressor as far as I know has never been replaced but I rebuilt it about 3 years ago maybe 4 so I think that going to be my next step since everything now seems to be working, albeit slowly.
 

Houm_WA

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If you were changing heights in succession as described above, the compressor could have just been getting hot and was protecting itself. I can go from Access to Off-Road height and as long as there is about a 2s break between switch presses, I don't get that message. Do the same thing but rapidly, and I can get the "rising slowly" message.
 

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