LR3 Compressor Issue Validation

[GORM]

So I was getting the dreaded C1A13 Pressure does not decrease when venting error. As I had already killed on compressor I simply replaced with same to make it ways as sometime soon I will go to springs. So I swapped Dunlop with an inexpensive one and was getting same errors - ZERO change. I changed the relay to the one sent with the unit.

Much on this topic pointed to an exhaust issue to check first. I pulled the thicker pilot exhaust value on the rear of the unit and other than it being noisy and scaring dogs as I drove by, no change. I then pulled the thinner pipe from the front of the unit that does to the exhaust and no change. Given this is a new compressor, I guess I was only validating the exhaust air muffler wasnt clogged. I also got C1A20 Pressure increases too slowly error during this testing. Makes sense as the air dryer now had a hole.

Seems to me I must move to the valve blocks. I've owned truck for 5 years and replaced rear (PITA) and removed, cleaned out and replaced the front vale block (easy). Next up the center one. Anyway, I just wanted input on what else I might check if center valve block comes up empty. It appears I will have a spare compressor as this does not seem to be the issue.

BTW, I have GapTool and went through multiple clears, restarts etc. One thing kept occurring was the truck showing in high mode when it wasn't. I do have NAV screen but did not see anything there leading me to any further conclusions.

Thanks in advance ...

 

[Howski]

Are the air springs losing pressure overnight and causing the vehicle to drop or it is only when the compressor is pumping out air?

 

[GORM]

Are the air springs losing pressure overnight and causing the vehicle to drop or it is only when the compressor is pumping out air?

I'm familiar with that one but I've had no issues lowering overnight.

Sometimes it fails after 5 minutes on road and sometimes fails less than 10 seconds after I start the car.

 

[GORM]

Update: So center valve block is ruled out, I removed and cleaned out. Actually, they was a lot of residue inside the 2 pieces. Despite this, zero change.

More info, possibly helpful. The gallery pressure cannot get to 259psi before the unit goes well over 250F and hits the thermal protection. I reflashed ECU, deflated and re-engaged System (somehow it allowed me to do that).

 

[GORM]

Another Update:
- removed air in,etc and Arne Compressor, still got the C1A13
- removed the pressure sensor, cleaned and re-installed, wasn’t encouraged by the one either

Then proceeded to watch stats on gap tool, as long as I did not try to raise suspension, the compressor would cycle.

- watched psi rise slowly until Compressor temp hit around 268F
- exhaust would open, pressure would drop drastically to around 30-40
- when unit cooled to around 225, and as long I did not raise truck, Compressor would kick off again, each time achieving a slightly higher pressure
- watched this do it 4 times and eventually hit 259 psi

As soon as I try to raise truck, fault code.

Running out of thoughts, while cleaning does not substitute repacking, tossing parts at problem like a stealer does not seem to make sense. I thought I might replace mid value block because $ not much higher than the pressure sensor which is part of it.

 

[sunrisehiker]

GORM,
By referring to inexpensive unit, do you mean that you have replaced Dunlop with cheap chinese copy, possibly Dorman ? If so, these units are known for being weak from the start and simply NOT being able to create enough pressure to inflate LR3 air suspension system. Some were lucky and Dorman worked for a few months getting noise and not working at all below 50F. Coincidence? Maybe, but Dunlop is not a champion either. Exhaust valve comes to mind, but you have already checked that.I have always have good luck with Hitachi unit maintaining it every two yeas and original one lasted me more than 10 years. am still on the second, from 2008 model and my service is limited to air dryer replacement from now and then. Good luck!

 

[GORM]

Yes on inexpensive compressor, knock off. However, I’m getting the same exact error codes as with old compressor so I’m not necessarily convinced another $200 (ha ha on me, $400) solves my problem.

Truck has 150k and on original height sensors, air springs and shocks so all in all, not awful.