Help with BMW DPF backpressure

[HolyRoach]

Hello everyone, is anyone able to assist me?

Here are the codes for my 2004 E60 525d (M57):
A sensor for the exhaust back-pressure (004CF3)
Problems with the DPF threshold or loading (481A/480A)
• 4166—Concerning DPF

I've already taken care of the exhaust temperature sensor in Bank 2 and the exhaust back-pressure sensor by replacing them with the proper ones.

After cleaning and inspecting, the pressure hoses and DPF ports appear to be clear.

No matter how much you turn off the engine, the live data will still display a constant of around 6.00 psi. It never goes below zero, though the last digits do flicker ever-so-slightly.

The sensor connector was measured with the engine off and the ignition on:
• Pin 1 → 5 V steady (excellent)
• When the sensor is connected, Pin 2 (signal) maintains a constant voltage of 2.6 V.
• (I'm assuming that ground is Pin 3).

Maintaining a constant 2.6 V signal voltage is independent of engine speed.

Is anyone familiar with this?

Then what should I do? Reset the adaptation/zero point, check the wiring, or is there something else I should look at?

Your input is valued.

I am grateful.

[Angurita]

First, I'd look at a wiring diagram to make sure that pins 1-2-3 are the ones you measured. Then, I'd backprobe the signal wire voltage at the ecu pin. There might be a shorted wire if the voltage is off and the ignition is off.

[HolyRoach]

I take it that you mean to connect the signal wire to an object that does not have voltage?

[Angurita]

no, what I mean is that the 2.6v could be coming from some other source, and the signal wire could be shorted to something (in the worst case scenario, the ddm). Not knowing the sensor data, pin values, and what they should be makes it difficult to determine.