The Mitsubishi Pajero Owners Club®

Gizandhp · Posted: Fri Dec 08, 2023 18:46 Post subject: P0401 EGR Flow Insufficient

For the last few months the Engine light has been coming on intermittently (on my 2015 3.2 DI-D Shogun Barbarian 4M41). Always P0401 fault code. I removed and cleaned the EGR valve (full of carbon on outlet side). Fault codes soon recurred. I tried Forte diesel treatment - no better. I removed inlet manifold air hose and sprayed a can of Liqui Moly Pro-Line Intake System Cleaner Diesel into the inlet and removed EGR valve again this time soaking it in WD40 for 30mins and got it very clean. I used my Topdon ArtiDigi 500 to plot EGR Valve position vs target position and valve position appears to track target perfectly. P0401 now occurs practically every time I use the car.

I’d be greatful for any advice or ideas to fix.

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rick1127 · Posted: Sun Dec 10, 2023 11:50 Post subject:

Hi pal theres a sensor just past the inlet butterfly flap that is the sensor that detects if theres a positive or negative pressure in the inlet.
thats the one that will tell you if there is enough flow from the egr.
Just check the sensor hasnt got blocked or isnt dirty.
you have checked all the pipes from the manifold through to the egr valve itself??
hope this is of help

Gizandhp · Posted: Sun Dec 10, 2023 16:55 Post subject:

Thanks rick1127, I wondered how the EGR flow was inferred.
I have checked the sensor port in the past, but today removed the tube to the sensor (MAP Sensor?), the sensor itself and made sure it was all clear. I haven’t had P0401 back yet but haven’t been very far. Fingers crossed it doesn’t come back!
The engine seems to run fine and no excessive smoke.
I did remove the pipe across the top of the engine to the EGR valve, this was pretty clean. I haven’t checked the valves on the top of the cooler and back to the exhaust - it looks to get a bit complicated around there.