Hello! I recently purchased a 2011 L322 (LHD). I has started throwing a code, C1A08-1C, indicating that the supply voltage to the pressure sensor is out of range. When I read the live data with IID tool, it shows 0.980V. Using a volt meter, I read 5V at the connector, both while plugged into the sensor and while unplugged from the sensor.

I assumed that supply voltage must be measured in the module and thought that the module must have an internal issue, so I bought a used module and swapped it out... but it gives the same result.

The pressure sensor will report higher voltages, ie I've seen 2+V from it, which aligns with me actually reading 5V at the connector.

I'm at a loss as to what/where the issue could be. The wiring is utterly simple back there, and a very short run between the switch and module, and it all measures correctly as best as I can tell. The module is connected to the rest of the system via the CAN bus, which... if there was a physical issue there, I'd expect a lot more problems?

Would love any insights that you might have. Thanks!

This morning, I decided to try and simply the circuit, so to speak. I started by disconnecting the height sensors, which are the other sensors receiving a 5V signal. No change with them disconnected. Of course, if there was a short there, maybe that isn't surprising.

Next, I pulled the module out from behind the fuseblock so that I could more easily test things. I started by pulling the small connector that contains the wiring to the pressure switch. Interestingly, even with the plug disconnected, the ECU reports .980V to it; I'm not very good with electricity, but this makes no sense to me... doesn't there have to be some resistance/ground for a current to be present?

I tried my "new, used" module again, and get the same result. I also pulled the "large, middle" plug to the ECU, no change. I couldn't pull the outer two plugs without the module shutting down.

At this point, I am out of ideas. I feel like it must be something relatively simple, but... I have no idea what.

Check for corroded fuses, I've had more than a few issues with EAS due to this. Open circuit voltages can be misleading as the control module will recognise something is disconnected, get a decent set of backprobe pins and an accurate voltmeter.

I'll take a look. But every other signal, function coming from the EAS module is working fine. Everything I measure says that this circuit is fine, too. I've checked continuity of the wires, checked them for shorts/grounds, etc. Everything is nominal according to my measurements. I've added jumper wires to ground, for the 5V line, etc. I've unplugged the connector from the ECU, it still reads .980V. I grounded the 5V line from the ECU and it did move, to 0.990V. I'm stumped.

Edit: I should also point out that when I clear codes, until the ECU runs its check, the car functions normally. I haven't figured out what triggers the code. Sometimes it seems immediate, other times it's a day.

Oh Im hoping you figured this out can you update me?

I have exactly the same issue; I cant reproduce it however; it seems like when I go uphill it triggers and I lose all values inthe GAP tool;

Update?

Thanks,

Dave

09 FFRR HSE
12 FFRR HSE

I replaced the air pressure sensor and it's been okay since then. The signal values are still bad, but I guess it isn't doing the check.

Where did you source the sensor? JLR? And did that fix the cycling as well? ANd did yours expell gas because my gallery is dropping from 200-35 lbs and also Ive bumped that sensor (were talking about the one on the EAS compressor valve body correct? Under the spare tire? I would think giving it a knock would produce same thing - did you try that?

Thanks,

Dave

My system worked fine, except when it stopped working because of the code. I believe it was sensor RQH500011. Yes, the one on the compressor valve body (I believe it's the only one). I probably got it from FCPEuro. I don't think giving it a knock would have achieved anything, but anything is possible!

Look at my post for Air Suspension Fault regarding the sensor issue. In my case I think the sensor went into error thinking there was a vacuum in the gallery compared to atmospheric pressures.
4x4Airseals do the sensor and desiccant kit along with an O ring kit for compressor service.

I don't think they do one for the ncj pressings one but i've asked. I do have a working or non weird identical compressors on my 12 but I am LOATHE to touch a running rangie.

Dave