Troubleshooting SH Code on a Primus IQ Brake Controller

Updated 07/19/2024 | Published 04/19/2015

Question:

Sh code and clicking noise on both trailer wheels whe promis iq os plugged... Jadore thé primus changed once beacuse we tought ut was a test ligot problem... Bus even with SH code thé brakes work well on the trailer is it normal that the trsiler brskes work even with a short on a wire?

asked by: Mathieu

Helpful 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 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.

It is odd that the controller seems to still work with the SH code being displayed, but I would still recommend you track down the short before continuing to use the controller as you may end up damaging the controller, or be left without brakes expectantly.

expert reply by: Jameson C

Mark

2/26/2020

My Primus break controller is flashing Er .. Er .. Er .. Er ..What does this code mean ? It’s been suggested there is an internal Controller fault and replacing the Controller will solve the problem ?

Chris R.

2/27/2020

The "E.r" error message on your Tekonsha Primus Brake Controller does indicate an internal fault that requires a full replacement. Unfortunately it's not something you can really troubleshoot, as something has gone wrong inside the controller itself. Replacing the unit will get you back on the road.

Michael

7/19/2024

Hello, I just wired up the tekonsha primos break controller and it’s showing a SH code. Code says there’s a short but I just wired the (blue) wire to the back of the vehicle and the trailer isn’t connected so I don’t understand why I’m getting this code

Jameson C.

7/19/2024

@Michael Try disconnecting the blue wire and see if the SH code goes away. If so, there's a short somewhere between where it connects to your vehicle wiring and the 7-way at the rear of the vehicle.