Troubleshooting the o9 Error on a Tekonsha Prodigy Trailer Brake Controller 2007 Chevy Silverado

Question:

I have an 07 classic body style GMC with a duramax. Every once in a while I get a o9 code. Its usually only when the truck is just started and goes away after a few minutes of driving. This is without a trailer attached, it may of happened once with a trailer attached but im not to worried about that since some of the trailers i tow have questionable wiring and i only tow them once or twice a year. I replaced the plug in adaptor that i soldiered together with one that doesnt have any soldier or butt connections. My next thought is to cut the white wire and ground it directly to the body, I assume it should go from the controller to a grounding point? I have gone through all the other connections and wires along the frame.

asked by: Jason A

Expert Reply:

On a brake controller, the best ground location would be the negative battery terminal so you can try that. This could be a combination of problems. Once you have a secure ground check the trailer connector on the truck for dirt and corrosion at the pins and the back of the connector where the wires attach. There could be a short to the brake output pin that makes the controller think there is a trailer attached.

To test the controller itself you will want to sever the blue wire a few inches back from the controller leaving enough space to re-attach if the controller is fine. Then use a circuit tester like # PTW2993 if needed to test the end of the blue wire coming out of the brake controller. It should only show power when you apply the manual override. If it shows power at any other time, then that indicates a problem inside the controller, and it will need to be replaced.

I have also included a link to a brake controller troubleshooting FAQ that should help.

expert reply by: Michael H