Troubleshooting Prodigy P2 Brake Controller on 2011 Audi Q5 Not Reading Trailer Brakes

Question:

Hi, I purchased a Tekonsha Prodigy II from you, and had it installed in my 2011 Audi Q5 by the dealer. It had an Audi towing package previously installed with the 7 prong plug. When i connect the trailer, which has electronic breaks, while all the lights on the trailer work, the Prodigy reads NC not connected. Is there any easy way to trouble shoot this? Im not convinced that the local dealer knows how exactly to install the Prodigy so im not sure theyll be able to trouble shoot it effectively...can you recommend someone locally who might be able to work it out? Im in Miami, FL. Thank you very much.

asked by: Erik B

Expert Reply:

The NC error code means that the brake controller isn't 'reading' the trailer. There are many things that might be causing the problem. I'd begin by determining if the problem is with the vehicle or the trailer wiring. Use a circuit tester like part # PTW2993 and ground the tester to the ground pin on the 7-way (see photo). Then, probe the brake controller output pin while a helper activates the manual brake switch on the underside of your Prodigy P2 brake controller.

If you get voltage on that pin with the manual brake switch, then the problem is in the trailer wiring. Begin with the connector on the trailer, examine it for damage and corrosion. If you can see white or green corrosion in the sockets, then the corrosion might be preventing the brake voltage from getting through. Follow the brake output circuit (usually a blue wire) from the connector to the brake magnets. Look for pinched wires and cracked or worn wire insulation. Check the connections at the brake magnets. One lead from each magnet should be grounded to the trailer frame, the other should connect to the brake output circuit.

I've linked you to an FAQ article that provides some troubleshooting hints.

As I'm sure you paid good money to the dealer, I'd insist they correct your installation.

expert reply by: Mike L