BMW fault code 9DFF

Trailer module

In the trailer module, code 9DFF 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.

AHM brake light: overload or short circuit to ground

Module version: Trailer module (AHM_70)

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 (E66) 2002–2008, 7 Series (E67) 2002–2008, X1 (E84) 2009–2015, X5 (E70) 2006–2013, X6 (E71) 2008–2014, X6 (E72) 2009–2011

AHM Reserve_DTC_09

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 9DFF 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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