BMW fault code 4AC5

Diesel electronics slave

4AC5 Oil quality sensor QLTCD

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 4AC5 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)

← 4AC2 All diesel electronics slave fault codes 4AC6 →