Fault code 2564: Diagnosis/troubleshooting

NOTE:

When troubleshooting, the status of the fault must be observed!
Use a suitable test cable or a trailer (which is definitely OK) to check whether the fault is present on the vehicle or whether it is recurring.

DIAGNOSIS/TROUBLESHOOTING PROCEDURE

Work instruction			Display OK	If not OK
1	Connect test cable (tool) or OK trailer to trailer socket and check whether functions are present or whether the fault is recurring		Fault exists in trailer; repair bulb/light, plug connection or wiring → End	Go to Step 2
2	Check fault memory in the trailer hitch control module for [F8] fault		'Open circuit' 'Short circuit to ground' - Light is not lit Go to Step 3 'Short circuit to B+' - Light is lit continuously Go to Step 5
3	Check wiring in vehicle between trailer hitch control module and trailer socket for an open circuit	Switch off ignition Pull off plug A on trailer hitch control module Measure resistance between pin 10 of plug A on trailer hitch control module and pin 7 of trailer socket	< 5 Ω Go to Step 4	Repair wire or replace wiring harness → End
4	Check wiring in vehicle between trailer hitch control module and trailer socket for a short circuit to ground	Check resistance between trailer socket, pin 7, and ground	∞ Ω Go to Step 5	Repair wire or replace wiring harness → End
5	Check wiring in vehicle between trailer hitch control module and trailer socket for a short circuit to B+ (see note)	Push on plug A of trailer hitch control module Switch on ignition Check voltage between trailer socket, pin 7, and ground	< 0.3 V Go to Step 6	Repair wire or replace wiring harness → End
6	Check ground leads	Measure resistance between trailer socket, pin 3, and vehicle ground	< 5 Ω Go to Step 7	Repair wire or replace wiring harness → End
7	Replace trailer hitch control module		→ End