BMW X3 2.0d: 2007 Model with AGR Seats

I have an X3 with an N47D20 engine and I'm getting these error codes.

003FF1 Air mass measurement (exceeded).
0040A4 DDE: Exhaust gas recirculation valve position, long-term drift.

I've now checked the air mass sensor (both its current and past readings) and also examined the control signals for the pressure transducer.

"The target value for the LL is approximately 280 mg/H, but the actual value I'm seeing is 580 mg/H, and the control signal is at 5%. If I apply vacuum to the EGR valve using a vacuum pump, I can adjust the actual value to match the target. There is sufficient vacuum pressure available at the pressure sensor for the EGR system. However, the pressure sensor solenoid valve is not being activated; it always shows 0.2 V."

I recently visited a friend who has an original tester, and we performed the AGR test. Here, the AGR is adjusted in 7 steps, from 15% to 62%, but during steps 4 and 5, the deviation is too large. During the test, I measured the voltage at the pressure sensor, which was approximately between 7.2 and 8.2 volts.

If I let the engine run in neutral, the control system also displays 62%, but after about a minute, it drops back to 5%. Even giving it some gas doesn't help to reactivate the EGR valve.

The pressure transducer has a resistance of 17 ohms and also switches when I briefly apply voltage to it, and the air mass reading decreases.
I've now tested it on another X3, and here the mass airflow sensor readings for "expected" and "actual" are very similar, and the control is around 57% at idle. After about a minute, it switches to 5%, but when I give it a sudden burst of throttle, it goes back up to 57%.

"Does anyone else experience this problem? The control unit doesn't ground the pressure sensor unless I run a diagnostic test."

Hi,

When using the tester to control it, is a specific, fixed duty cycle simply set, or should the motor control unit attempt to regulate based on a certain amount of air mass?

Does the "5% EGR control" setting for the car mean that the EGR valve is almost completely closed or almost completely open?
Could it be that the solenoid valve for adjusting the vacuum pressure to the EGR valve has 3 connections, and the connection for the EGR valve was accidentally connected to the wrong port?

Is the engine control unit (ECU) software original, and has there been no attempt to disable the EGR system via software?

Best regards, Rainer.

When controlling the system, a percentage value is specified, and the system attempts to reach that position. There's a potentiometer on the vacuum sensor, which I assume is used for control.

"5% are completely closed, which is why the actual air mass value is so high."
The solenoid valve has two ports, and the software is genuine.

I just tried the solenoid valve from a 320d, and surprisingly, it now controls the solenoid valve with a duty cycle of 57%. (LL)

My initial assumption was that it would work, even when tested with battery voltage and confirmed by the tester.
Widerstandswert soll 15-30 Ohm. Mine is 17 Ohms.

Unfortunately, I didn't have anything to try beforehand.

We are very spoiled by the diagnostic capabilities of VCDS.
With BMW, you can't really see any measurement values. When controlling the solenoid valve, you only see the percentage it *wants* to be at, but not the actual value it *is* at.

Thank you, Rainer.

Feedback: I replaced the pressure sensor and the EGR system is working again.

It didn't work for very long.

I then tested the potentiometer on the vacuum sensor of the EGR system using a multimeter and a vacuum pump, and it showed an infinite resistance value at a certain level of vacuum.
You only needed to slightly increase or decrease the vacuum pressure (by about 20 mbar), and the value would adjust accordingly. Hopefully, that's it now.

Thank you for your feedback!