Fault code 2539: Diagnosis/troubleshooting

DIAGNOSIS/TROUBLESHOOTING PROCEDURE

Work instruction			Display OK	If not OK
1	Connect test cable (tool) to trailer socket and check whether functions are present and whether the fault occurs again		Fault does not occur again > Fault exists in trailer; repair bulb, plug connector or wiring. → End	Go to Step 2
2	Check fault memory in the trailer hitch control module for [F8] fault		'Open circuit' Go to Step 3 'Short circuit to ground' Go to Step 4 'Short circuit to B+' 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. Check resistance between pin 16 plug A on trailer hitch control module and pin 9 (pin 5 in North America) of trailer socket.	< 5 Ω Go to Step 6	Repair wiring or replace wiring harness. → End
4	Check wiring in vehicle between trailer hitch control module and trailer socket for a short circuit to ground	Switch off ignition. Pull off plug A on trailer hitch control module. Check resistance between trailer socket, pin 9, (pin 5 in North America) and ground.	∞ Ω Go to Step 6	Repair wiring 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)	Pull off plug A on trailer hitch control module. Switch on ignition. Check voltage between trailer socket, pin 9, and ground (pin 5 in North America).	< 0.3 V Go to Step 6	Repair wiring or replace wiring harness. → End
6	Check ground lead	Measure resistance between trailer socket, pin 9, and vehicle ground (pin 5 in North America).	< 5 Ω Go to Step 7	Repair wiring or replace wiring harness. → End
7	Replace trailer hitch control module		→ End