[jonno1805]

Hi Guys,

I have an E90 320d and when I was driving from Norwich to Southampton a few weeks ago I suddenly had a loss of power after about 90 miles, I was going up hill on a motorway and put my foot down and nothing happened, I had to change down to 4th just to keep going. No warnings on dash, no other symptoms. I plugged in my Carista code reader and used it with the Bimmertools app which gave the following:

4530: Charge pressure control, control deviation
40E9: Exhaust gas return controller, position control
4C9F: Exhaust gas return valve, plausibility
4507: Exhaust gas return control, control deviation

I changed the EGR valve (flying saucer shaped one) and checked that the vacuum lines from the pressure controller to the egr could hold a vacuum, and that the line from the pressure controller to the egr cooler could hold a vacuum (they both did). but the error 40E9 came back almost immediately.

The loss of power was still intermittent so I checked the turbo actuator, (which is electronic not vac). With the engine off I moved the actuator arm up and down, it was a little stiff but I have no reference for what it should feel like. I then started the car and used Bimmertools to command the actuator to 5% then 95% and the arm moved accordingly, seemingly without issue.

I noticed when the issue was occurring the actual air flow value was about half of the expected, and the boost barely moved. I removed the MAF sensor connector and continued driving, and it made no difference. I cleaned the MAP sensor (which was very dirty), no difference...

When I parked it up after a test drive I left the engine running and watched the turbo actuator, and it was moving up and down with the car just idling. It would go from 10% to 95%, is that normal?

Also when shutting down the engine when the issue is happening the engine shudders, which it doesn't when the issue isn't happening. (not sure if relevant).

TLDR: Got EGR error codes and intermittent low power, changed EGR and code 40E9 is still occasionally there, as well as low power.

Any help would be greatly appreciated,

Thanks,