I looked at my manual and could only find that the supply voltage to that sensor is 5.0V

 

Well that sort of makes sense. 4.9 for 14 psi and maybe .1 for 240 ish.

Either way I cleaned out the reservoir valve block and put in new O rings, but unfortunately I have driven it much I am not sure if the light will stay out or not. I will report back at the end of the week and let you know if it solved the issue.

 

New O-Rings did not solve the problem.
When I removed the valve block there was still pressure in the reservoir so I think that line is OK. I am going to pull the line from the compressor to the valve block and see if it is restricted. I still suspect the sensor may be bad. Cost of a sensor is 3/4 the cost of the valve block so I think I will capture some more live data before I go that route.
After that, I guess it is tearing into the AKM compressor.

 

just curious if you were able to figure out your problem. I know this was a long time ago. I am getting this error after installing a cheap valve block:C1A18-64 (AF) Pressure increases too rapid when filling reservoir - Algorithm based failure - signal plausibility failure

At 214209 mi

Triggered on 15-11-2025 16:23:23

 

Sensor in distribution valve was bad. I replaced the whole valve block and it worked fine after that.

 

good to know! What valve block did you buy and how much did you pay?

 

I don't recall exactly which one or from who, but I tend to buy OEM or LR parts when it comes to the air suspension. Most likely an OEM option.

Jeff

 

I have this same code and an amber light but only when it's cold outside, and I can still raise and lower and use Terrain Response so I haven't bothered to do much.
It's also an aftermarket valve block. Sometimes you do only get what you pay for.