Fault Code 2577

Fault code 2577

Activation of electrical brakes, trailer

WARNING:
Increased danger of accident due to altered handling while towing a trailer and due to altered braking effect

NOTE:
- This fault code is used to monitor the signal leads for a retrofitted control unit of electrical trailer brakes. Faults in the trailer of their components are not detected.
- This fault code can only occur for NAR (North America) coding.
- This fault, together with all lighting faults, is saved only by the last trailer. This means that if another trailer is detected (trailer in socket), all lighting faults are first erased.

Diagnostic conditions
- Ignition on
- Trailer hitch control module, internal function test
- Trailer detected through plug in trailer socket

Possible causes of fault
- Retrofitted electrical brakes control unit (trailer) faulty
- Short circuit to ground or B+ in signal lead
- Trailer hitch control module

Affected pins
Trailer hitch control module, plug A:
- Pin 13

Control module plug, electrical brakes (retrofit), trailer
- Pin 3

Diagnosis/troubleshooting

NOTE:
- When troubleshooting, the status of the fault must be observed.
- "Open circuit" fault type is not monitored due to possibility of component fault.
- A short circuit to B+ can also be a short circuit to supply leads of other loads. The leads must be supplied with power for test purposes.