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Troubleshooting Tekonsha Prodigy P2 Brake Controller with Intermittent Braking


This is on a 1999 Toyota 4Runner.Tekonsha Prodigy P2 Trailer Brake Controller. I am also having a strange issue with my brakes. It happened suddenly on my last trip and continues today. This is what I have done since then. I inspected the brakes, visually checked all wires/connections under the car and the trailer and could not find any glaring issue. I checked the magnets and had the hubs inspected. I was told the magnets and hubs are fine. Next, I checked the magnets and they engage. Next, with a person applying the brakes I wiggled every wire I could think of multiple times under the car and trailer and never even once did I get an error code of any kind from the controller. I replaced the connector at the trailer end. The connector on the car is new. When the car is parked with engine off, it shows normal condition. The second I start the car and roll the car forward and apply the brakes I get an error code 5H or PL and the brakes jerk then release, jerk then release. Although the instructions are not clear on how to exactly check the controller blue wire, I cut as instructed and then using a volt meter, grounded the black probe and touched the red probe to the blue wire on controller end. It shows about 8.5v with car off with manual override at full and about 12.8v with car at idle with manual override on full. How much its supposed to show is not clear but I assumed any voltage means a signal and that is what Im looking for? In a previous question by Michael S, they say they get a clicking noise. I noticed this too as a symptom. You had mentioned the clicking only happens with manual override, however I have this condition when applying the brakes. I have been attempting to isolate my problems but am having a time of it. If what you say is true about clicking happens with high signal output with manual override, it seems to me when I apply the brakes I am somehow sending too much signal to the brakes and the jerking must be when the prodigy shuts off and then resets. This is the only thing I can think of. Why its happening is beyond me.


Expert Reply:

The error codes you are getting with your Prodigy P2 Brake Controller # 90885 help explain why you are getting intermittent braking. The "S.H" means you have a short in the brake wire during an idle connection and the "P.L." is a power interruption when you hit the brake pedal. This makes sense in the way you described it as I imagine the S.H. is happening before you move the car and the P.L. is happening when you brake.

I imagine there is a short on the blue brake wire somewhere along its route from controller to your brakes, which you can verify by testing the brake output pin on the 7-way socket (which will be at the 5 o'clock position); If it shows power any other time then there is a short. This can be a pain to find but you will need to trace your wiring to find the short. If it tests fine then take a look at the wires going to the brake magnets and thoroughly inspect them as they may be may be pinched or otherwise damaged. I know you said you did this already but another inspection is going to be needed as it can be difficult to see sometimes.

Additionally, and I'm not sure if you did this specifically or not, but the blue wire coming out of the controller should only have power when you apply the manual override; if it shows power at idle then there is an issue with the controller and it will need to be replaced.

Hopefully this was helpful and you can find the solution. I've also added some links to help articles on troubleshooting brake controllers which I recommend taking a look at.

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expert reply by:
Kyle S

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