Hello
New 2011 QX56 owner. Learning the car, unfortunately, missed some problems buying it, so here I am.
First problem: sagging rear end. Air bags appear to be intact. Comp does not appear to start, I'll try to jump it tomorrow.
I scanned system today with Nissan s/w on Foxtel scanner:

I have C1 803 EXH SOLENOID error code in suspension compressor section module.
Is that solenoid a separate unit or it it is integrated into the pump?

I'll also jump height level sensor, just to make sure that it is OK. Showed fine on scanner.

Thank you

If it's the same as the Armadas (which I expect it is), the solenoid is integrated with the pump assembly.

OK, so if I can't jump compressor, then it's comp replacement, right?

Correct. If the compressor won't run, check the fuse first, of course.

Silly it may sound, I can't find air suspension relay. Schematics online say it's in the under the hood fuse box 2, and mine is completely different. I already tried.

The relay is in the Fuse & Relay Box at the passenger rear of the engine box, near the IPDM. See PG-146 here for the layout:
https://www.nicoclub.com/service-manual ... 1%2FPG.pdf

VStar650CL wrote: ↑

Sat Dec 16, 2023 7:59 am

The relay is in the Fuse & Relay Box at the passenger rear of the engine box, near the IPDM. See PG-146 here for the layout:
https://www.nicoclub.com/service-manual ... 1%2FPG.pdf

Great, thank you. Do you happen to know which one of them "E" numbers is the solenoid? Or, where in that manual is the items list?

There's a whole section for the suspension control system, you'll find pretty much all that info here:
https://www.nicoclub.com/service-manual ... %2FSCS.pdf

Relay is behind the fuse box, one to the far left, facing the vehicle. There's

Sorry for the gaffe in my previous post, it's far RIGHT not left.


OK, here's update. Got truck up on the lift, disconnected comp plug, supplied 12V from 100% charged battery. Comp kinda just does little bzzz and that's it. Like as if it wants to kick in, but can't. Out of curiosity, I reconnected the harness, removed height sensor mount from the lower control arm, set sensor arm so that it'd indicate very sagged vehicle, and turned system on. Gave it about 2 minutes, nothing happened.
Then, disconnected sensor harness, inserted 3 pins into the connector from the main power supply, and jumped the plug, with the system on. Nothing. Not even a bzz from comp.
Am I safe to presume that comp is dead and, possibly, the sensor too?
From what I can tell, trunk area undercarriage of this truck was in the salt water. Hitch, lower control arms are rusted. Not bad, but some paint is gone and some rust flakes are here and there.
My gut tells me, it towed a boat and was in the water, when they pulled it out. Certainly, comp then was immersed.

Definitely sounds like the compressor and valving have seen better days.

Time for new one then. No big deal.