BMW fault code 940D

Trailer module

AHM: Trailer tow hitch not locked

Module version: Trailer module (AHM_E65)

In: 1 Series (E87) 2004–2011, 1 Series (E82) 2007–2013, 1 Series (E81) 2007–2011, 1 Series (E88) 2008–2013, 3 Series (E90) 2005–2012, 3 Series (E91) 2005–2012, 3 Series (E92) 2006–2013, 3 Series (E93) 2007–2013, 5 Series (E60) 2003–2010, 5 Series (E61) 2004–2010, 6 Series (E63) 2003–2010, 6 Series (E64) 2004–2010, 7 Series (E65) 2001–2008, 7 Series (E67) 2002–2008, 7 Series (E66) 2002–2008, X1 (E84) 2009–2015, X5 (E70) 2006–2013, X6 (E71) 2008–2014, X6 (E72) 2009–2011

Reading and clearing it

Fault code 940D is a BMW code, stored in the car's trailer module, 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 trailer module is on: 5 Series (E60), 5 Series (E61), 6 Series (E63), 6 Series (E64), 7 Series (E65), 7 Series (E66), 7 Series (E67), X5 (E70), X6 (E71), X6 (E72), 1 Series (E81), 1 Series (E82), X3 (E83), X1 (E84), 1 Series (E87), 1 Series (E88), Z4 (E89), 3 Series (E90), 3 Series (E91), 3 Series (E92), 3 Series (E93)

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