Troubleshooting an SH Code on the Tekonsha PRIMUS IQ Electronic Brake Controller # TK90160

Question:

we need a troubleshooting chart for a primus 90160 brake system. We have a SH code showing now,can we find a chart anywhere? We had one but the ink is faded and cant read it.

asked by: Dave B

Expert Reply:

If you click on the link that I have provided for the installation instructions, you can see the troubleshooting chart just below the installation details.

The SH code that you see on your Tekonsha PRIMUS IQ brake controller indicates there is a short somewhere on the brake output circuit when idle, or when the brake pedal is not being pressed. Tekonsha states that this issue can sometimes be caused by some test lights if you are using test lights. To troubleshoot this issue, start by disconnecting your trailer and inspecting the trailer and vehicle side connectors for corrosion build up and clean or replace parts as needed to see if that fixes the issue.

If that does not resolve the issue, then use a circuit tester, like part # PTW2993, to test the brake output pin on the vehicle side trailer connector (the pin in the 5 oclock position) for voltage when the manual override is activated. If you do not have a signal on the brake wire pin, then cut the blue wire about 6 inches back from the brake controller and test for signal at that point. If you do not have a signal there, then there may be an internal issue with the brake controller, and it will need to be replaced.

If you do have signal at that point, then inspect the brake wire between the brake controller and the vehicle trailer connector. This will be the blue wire coming from the brake controller. Check for any pinched, frayed or damaged sections of wire that could cause a short. If you have factory installed trailer wiring, then inspect as much of the wire that you can see.

If the SH code appears when your trailer is connected, then there could be short on the brake wire on the trailer. First, inspect the ground connections for the trailer connector and the brake assemblies. A poor ground connection can cause many issues. If the ground connections are okay, then inspect the brake wire between the trailer connector and the brake assemblies for any pinched, frayed or damaged sections. If you do not find any issue with the trailer wiring, then you may also want to inspect the trailer brake magnets for abnormal wear. If you can see the copper windings on the surface of the brake magnets, then I recommend replacing the brake magnets.

I have attached a wiring FAQ article along with the installation instructions for the brake controller for you to check out. This article should prove helpful when troubleshooting your trailer wiring.

If you are unable to find the cause of your issue or a solution, then let me know what you come up with after following these steps and we can do further troubleshooting.

expert reply by: John H

Anthony S.

7/31/2020

Bought this brake controller and installed immediately said SH when installed.found wire from controller to 7 way was bad.i replaced it and still shows sh. Can a different wire cause sh or only blue wire?

Jon G.

8/10/2020

Any wire that is connected to the trailer brake circuit can cause that SH "short" code. Since you already replaced the blue wire I recommend checking the ground (white) wire and make sure it's connected to a clean, bare-metal surface. You also want to ensure that the vehicle and trailer connectors are clean and free of any corrosion or debris. If you're getting this code with the trailer connected the the issue could also be on any of the power or ground wires for the brakes on your trailer side of things.

Albert W.

5/11/2020

I have an error code . . Can you tell me what this means. It was just reinstalled in my 2020 _ _ Two dots on top and two dashes on the bottom of display Silverado Last week by Camping World, Ashville, NC

Chris R.

5/11/2020

This might just be an indication that the controller isn't mounted at a proper angle. Try angling it just a bit higher. The front of the Primus IQ needs to be horizontal and the tilt angle needs to be within 0 and 70 degrees. If adjusting this doesn't clear the error please let me know.

Albert ..

5/11/2020

I tried to get the controller as straight as possible but still getting the same code. . . - - Two dots above two dashes?

Chris R.

5/14/2020

Thanks for the info - is this a constant error code or something that only pops up when applying the brakes, etc? Have you tried applying the manual override or hitting the brakes to see if the display changes?

Thomas

5/8/2020

This was very helpful! I also am getting an SH code on my brand new controller. I hooked everything up and made a terrible mistake by switching my battery connections. For some reason, I mixed myself up at the final connection, even though I had it totally prepared correctly. I replaced the circuit breakers hoping that I did not fry the controller but with new breakers, I still get the SH code. When I check the signal, my tester lights up when I check the red wire by depressing the brake pedal, but I get nothing when I test the blue wire by pressing the manual brake slider/button. Did I fry my controller and need to get a different one or is there something I might be missing?

Chris R.

5/11/2020

It's not the best sign that you aren't getting any power on the blue wire with the manual override activated. Are you testing the blue wire right behind the controller, or further down the circuit (closer to the 7-Way at the bumper)? Also, if you haven't already, test this blue wire again after cutting it 6 or 7 inches back from the controller. This just isolates your testing to the brake controller itself (and rules out any potential causes with the 7-Way or wiring along the vehicle). If you still don't get power when doing this then the controller is indeed bad and needs to be replaced.

Thomas

5/14/2020

@ChrisR Thank you for clarifying! Yes, I checked it at the trailer connection, just behind the controller, and farther down the line...too bad for my mistake! Gosh, I just got going too fast at the very end!