Hello,

Well here goes the Land Rover technical helpline again.

I have been receiving alerts on the message centre saying that there is a significant EAS issue. RED light and max 30 km/h suggestion.

So my code reader gave me a code and a description as follows:
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C1 A1 3-64 INTERMITTENT
Pressure does not decrease when venting gallery.
*

I am thinking it is a simple fix if I can find out where the galleries (front and rear) vent pressure to lower the suspension. I know the front one is mounted near the front right corner on the back side of the bumper, but where is the rear vent?

Thanks for any suggestions as well.

 

Ok the schematic I am looking at, has the pilot exhaust solenoid as part of the compressor. If I understand the system right, that is the only place that it vents from. It is located between the dryer and the compressor, so that everytime the system vents, moisture trapped in the dryer is blown out, at least thats the theory.

PILOT EXHAUST VALVE
"A solenoid-operated pilot exhaust valve is connected to the air delivery gallery, downstream of the air dryer. When the solenoid is energized, the pilot valve opens and pilot air moves the main compressor exhaust valve plunger to deflate the air springs as required. Pressurized air from the air springs and/or reservoir passes through the reservoir control valve to the air supply unit. The solenoid has a resistance value of 4 ohms at a temperature of 20 degrees C (68 F)"

EXHAUST VALVE
"The exhaust valve has three functions. It operates in conjunction with the pilot exhaust valve to allow air to be exhausted from the air springs and/or the reservoir as described previously. The valve also protects the system from over-pressure, since it is connected into the main pressure gallery which is always subject to the system pressure available in either the air springs or the reservoir. The valve restricts the maximum operating pressure to between 333.5 and 370 lbf/in2 (23.0 to 25.5 bar)"

Now I should point out that this is talking about the Hitachi compressor, and I am not sure how different the AMK is, but what I would do is try to find the exhaust solenoid on the compressor, and test resistance across it to see if it is open or gives you a value of 4 ohms

 

Thanks for the write up.

This all makes perfect sense, but know I wonder how the system vents air from individual springs, or; if the springs are connected from one side to the other, but independent from front to back.

Say one is towing a trailer and then removes the trailer from the tow ball. This would require air to be vented in the rear to re-level the Rover.

My thinking is that the lines from individual springs, or pairs of springs could be plugged, pinched or otherwise restricted while the main pilot valve is otherwise working properly.

I may just have to call a dealer and ask about any common issues.

 

If I had a scanner I could show you a schematic drawing. The air 'System' consists of three valve blocks, a compressor (land rover calls this the air supply unit) and a reservoir. Front and rear valve blocks are identical. They consist of three solenoids. 2 called corner valves that connect to each of the air bags and one valve called the cross-link that connects the two bags together. The central valve block called the reservoir valve block, has the pressure sensor for the system, as well as a reservoir valve. That controls air flow into and out of the reservoir. This is also were the compressor ties in as well. Note that there is no isolation valve between the compressor and the system, and that the compressor does not directly feed the reservoir. It feeds air into what is essentially just the three valve blocks and the tubes that connect them. Land Rover refers to this as the Gallery.

To answer your question, to vent from individual springs the LR3 would open the appropriate corner valve for which spring it wants to deflate, and the pilot exhaust solenoid. To inflate this spring, it would open the same corner valve, and the reservoir valve. However, if the reservoir did not have sufficient air PSI then it would energize the compressor. If the problem was with just a single bag. Lets say a pinched line. That bag would never be able to pass its air to the gallery, through its corner valve, and then to the atmosphere, through the pilot exhaust valve. So the gallery wouldn't have an issue with venting, only that single bag. Remember the only pressure sensor monitors gallery pressure, and your code is saying its having problems with gallery pressure not reducing, which strongly suggests either the pilot exhaust solenoid is bad or the exhaust valve is stuck

 

Like usual, the problem is gone. All by itself. Lasted a week and then as soon as I ask how to fix it... gone.

At least the information shared remains for future reference.