Discovery 3 Random intermittent errors.

I have an intermittent problem – I get:

Orange suspension light
Orange stability light
Orange coolant light

Here are the codes when I scan:

🚙 ECM (Engine Control Module)

P0402-22 – EGR Flow Excessive → EGR valve sticking open or carbon build-up. Can cause rough idle, smoke, or limp mode.
P000E-22 – Fuel Volume Regulator Control Exceeded Learning Limit → The fuel metering valve on the high-pressure pump is struggling to control flow. Often dirty fuel, failing metering valve, or pump wear.
P0087-00 – Fuel Rail Pressure Too Low → Rail pressure drop under load. Can be related to the above fault — HP pump, fuel filter restriction, low-pressure supply pump, or injector leakback.

👉 These three tie together: likely fuel delivery issue (dirty filter, weak HP pump, metering valve, or injector return leak).

🏔️ ATCM (All Terrain Control Module)

U0401, U0402, U0416 – Invalid Data Received → These are historic comms faults. Usually thrown when engine/trans/suspension modules hiccup or are in limp mode.
👉 Not usually a direct fault, but a side-effect of the ECM errors.

🛞 RLM (Ride Level Control Module)

C1A36-01 – Exhaust Valve (Intermittent) → Common D3/D4 fault. Exhaust solenoid in the centre valve block is sticky or leaking. Can cause random lowering or “suspension fault” messages.
U0416-86 – Invalid Data from VDC → Again, usually knock-on comms glitch.
U2000-67 – Motor Temperature (Intermittent) → Compressor over-temp. Either the compressor is tired, or it’s overworking due to leaks.
C1130-66 – Air Spring Air Supply (Intermittent) → The system saw gallery pressure not behaving as expected. Could be related to the exhaust valve leak, reservoir valve, or compressor output dropping.

👉 These confirm your suspected leak / valve block issue.

📊 IPC (Cluster)

U0132 – Lost Comms With RLM (Intermittent) → Suspension module dropped off the CAN bus briefly (often if it faults/reboots).
U0184 – Lost Comms With Audio Unit (Permanent) → Harmless if your stereo works. Could be an aftermarket unit or dead MOST bus link.

⚙️ TCM (Transmission Control Module)

U2023 – Fault Received From External Node (Intermittent) → Just means it got a bad message, usually from ECM.

[UPDATE 25/8/2025] Not sure what exactly seemed to improve things, but I have done the following which seemed to help (dont seem to be getting the errors)

New front valve block (feel like the old one was OK)
Rebuilt the exhaust valve and re lubricated.
Cleaned the AMK compressor and re sealed it.
Rebuild the centre valve block.
Pulled the foam from the compressor intake filter (it was disintegrating)
Squirt some silicone lubricant down the intake line.

UPDATE: So after all this. I replaced the fuel filter (saw that recommendation on a few forums) the errors seem to have vanished on the power issues.

I also had the suspension error. I pulled the compressor and found that the cylinder was scored, and the piston ring was completely worn (the small end piston) After replacing that, things seem to have improved! I do have a slow gallery pressure drop and trying to work out if this is normal or not. Ill keep you posted!

Here is the video of the worn/damaged compressor cylinder and piston:

[Update] 9/25/2025 – the fuel filter seemed to help a little. And now the error comes back. Im getting a consistent p2290-00 error. Injector control pressure too low. – So it continues…

[Update] 9/26/2025 – Alot of online info is leading me to fuel filter and low pressure fuel pump. Im ordering these two items:

shcrader to presta hose (so I can attach to the low pressure fuel line) https://www.amazon.com.au/dp/B0DKH8MLP7?psc=1&smid=A2X0NPQ5KYNQQ2

and this guage will help to read pressures (I wasnt sure if the included fittings would attach to the schrader):

https://www.amazon.com.au/dp/B08P4P97H2?ref=ppx_yo2ov_dt_b_fed_asin_title

Ill keep things updated as I go.

[Update] 9/28/2025 – Well I got my parts and installed them on the car. I taped the guage to the windshield, and went up a hill near my place in 2nd gear to load things up. The low fuel pressure went negative! Check it out below:

[UPDATE] 9/29/2025 – Well I did some flow rate testing. One thing I noticed is that with the schrader valve removed, I get a more accurate reading, note the flow rate differences!

It does seem like my flow rate is ok at the moment. So then why the large vacuum on throttle? Next thing ill do is test for amp draw.