BMW fault code 4A40

Diesel electronics slave

In the diesel electronics slave, code 4A40 means different things depending on the version of the module in the car. Find your car below; the app shows the right one for yours.

DDE2: EWS interface error

Module version: Diesel electronics slave (D51SM670)

Which BMWs have this version depends on the engine and equipment, so we don't list them here; AutoLingo for BMW reads which version your car has.

4A40 EWS interface error

Module version: Diesel electronics slave (D63SM670)

Which BMWs have this version depends on the engine and equipment, so we don't list them here; AutoLingo for BMW reads which version your car has.

Reading and clearing it

Fault code 4A40 is a BMW code, stored in the car's diesel electronics slave, not a generic OBD2 code (P0xxx): a generic OBD2 reader only reaches the engine's emissions faults, so it won't show it. AutoLingo for BMW reads it with BMW's own diagnostic protocols, in plain English, with the details the module stored about it, and clears it after a repair. If a fault comes right back after it's cleared, the problem is still there.

The diesel electronics slave is on: 7 Series (E65), 7 Series (E66), 7 Series (E67)

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