Trailer Break Override triggers ABS and VSC dash light

Update:

The new harness should be in Tekonsha's distribution center by end of this month and in their warehouses for shipping by the first week of July.
 
Alright...
I just had an email conversation with their tech support - The short version is that I asked what was different in the new harness, the answer is a 1 amp diode (any voltage above 15v should work) installed in the red line...
I am not going to order a new harness, I'm just going to add a diode.
Here are some diodes that would work fine:
Amazon.com: Install Bay Diodes 3 Amp 20 Pack- D3: Car Electronics
While $5.43 is cheap in general it's expensive for diodes... but it certainly is easy to get them this way!

Full email thread with headers removed below:

The following message has been sent from the Tekonsha website on*Wednesday, June 17, 2015:
Attention:
Technical Support
From:
Andre Xxxx (*xxxxx*)
Contact Number:
716-xxx-xxxx
Subject:
VSC/ABS light on when using P3 and adapter harness
Message:
Hello,I recently installed my P3 in my Toyota 4Runner. When using the manual brake activation lever sometimes my ABS and VSC lights come on. They go off after the vehicle is turned off and back on.I have taken it to my Toyota dealer who could find no problem with the vehicle...What should I do?

On Jun 17, 2015, at 1:20 PM, Danny Dunn <[email protected]> wrote:
*
Andre,
*
Thank you for contacting Tech Support. We are in the process of making a brake control harness for the 2014-2015 4Runner, it should be available the first or second week of July. We had only heard of an issue on the 4Runners, like this, about two months ago. We are trying to expedite the manufacturing of the harness. It will have a diode in the red wire to prevent back feeding into the brake light circuit of the vehicle. The Tekonsha 3041 is not available yet. I will keep this email, and inform you when the harness is ready.
*
*
Best Regards,
Dan
*
Danny Dunn
Technical Service Coordinator
Cequent Performance Products (Electrical Division)
101 Spires Parkway
Tekonsha, MI.* 49092
(888) 785-5832

Dan,
Thanks for the reply…
Could you provide the value of the diode? I would be more than happy to just modify my current install… I’d dislike buying the same harness twice for the pennies it would cost to solder in a diode and add some heat shrink to it…
Thanks!
Andre

Andre,
*
We are using a 1 amp diode in our harness.
*
Dan
 
Watching this closely as I use a P3 and regularly tow a light trailer with electric brakes. Haven't set up the P3 yet on my new 4 runner. Thanks for the informative posts!
 
Harness Modification

You can do it!

photi-albums-trailer+brake+harness+mod-picture33836-unmodified-harness.jpg


photi-albums-trailer+brake+harness+mod-picture33830-red-wire.jpg


photi-albums-trailer+brake+harness+mod-picture33831-harness-section-removed.jpg


photi-albums-trailer+brake+harness+mod-picture33832-heat-shrink-cut-diode.jpg


photi-albums-trailer+brake+harness+mod-picture33833-soldering-diode-into-harness.jpg


photi-albums-trailer+brake+harness+mod-picture33834-diode-installed.jpg


photi-albums-trailer+brake+harness+mod-picture33835-heat-shrink-added.jpg


No more codes!
 
I just installed a Hopkins Insight on my 15 SR5P and get the same fault. I will be calling Hopkins tomorrow for advice, although adding the diode looks to be in my future.

This unit is a great choice for out of the way mounting.
 
Just ordered the diodes!

Thank you for this. I so hope it works!

You're welcome... just make sure to observe polarity -
A diode allows power to flow from the anode to the cathode but not the reverse -
In our case we want power to move from the truck to the brake controller, but not back.

Usually the cathode is the side with the ring, observe the orientation in my pics...
Anode to truck side, cathode to brake controller side.

Sorry for the probably unneeded basics! I think gm350reratliff gave a far more complete explanation near the beginning of the thread, I just took pics...
 
You're welcome... just make sure to observe polarity -
A diode allows power to flow from the anode to the cathode but not the reverse -
In our case we want power to move from the truck to the brake controller, but not back.

Usually the cathode is the side with the ring, observe the orientation in my pics...
Anode to truck side, cathode to brake controller side.

Sorry for the probably unneeded basics! I think gm350reratliff gave a far more complete explanation near the beginning of the thread, I just took pics...
The NEEDED basics are welcomed. The pics detail it perfectly and your follow up post above was helpful.

Thank you!
 
I spoke to someone at Hopkins and they said they are also working on a harness for the 2015 Toyota's. He said that on the unit I installed, the controller monitors voltage on the red wire to know when the brakes are being applied, and applies voltage to this wire when using the manual trailer brake override for brake light operation. This would mean a diode would not work properly on the Hopkins unit. Waiting for Hopkins to get back to me......
 
Model year specific...

No problems with my Tekonsha Prodigy P3 after towing almost 4,000 miles. Tested the manual override - everything works as it should.

Are you guys using the plug-and-play wiring harness (p/n 3040-P)? Note this is not the one that came with the truck, or with the controller. It has to be purchased separately:

Amazon.com: Tekonsha 3040-P Brake Control Wiring Adapter for Toyota: Automotive

From what I can see it's a problem with 14+ 4runners. I little change in the ECU flash and now folks have to do this. Silly Toyota.
 
I spoke to someone at Hopkins and they said they are also working on a harness for the 2015 Toyota's. He said that on the unit I installed, the controller monitors voltage on the red wire to know when the brakes are being applied, and applies voltage to this wire when using the manual trailer brake override for brake light operation. This would mean a diode would not work properly on the Hopkins unit. Waiting for Hopkins to get back to me......

All brake controllers do this. A diode or relay will work when installed properly.


From what I can see it's a problem with 14+ 4runners. I little change in the ECU flash and now folks have to do this. Silly Toyota.

I think it's more than just a flash. My guess is Toyota either forgot to install the diode in the vehicle harness or got a batch of bad diodes that allow voltage to travel both directions. I Doubt Toyota will ever acknowledge this therefore it will never be a warranty fix.
 
I am not sure I want to eliminate the brake light function with override unless that is the only option. And I sure don't want to hear a relay click every time I hit the brakes.

I checked to see if any codes were stored, there were none.

If anyone has the ability to capture any codes before shutting off the vehicle, that may be helpful to Toyota. If they get enough calls on this, maybe they will work this issue......maybe........
 
new harness

I received the 3041-p harness today from Cequent America, Tekonsha's Mfg. There tech service has been great. These guy's stand behind their product's. I will install and test it tomorrow.
 
I received a new harness from Tekonsha. Will install this weekend.

Any luck? Just wondering if I should proceed with a diode install or order new harness. Have you figured out why you couldn't get the wheels to lock? I am having same issue. Thanks.
 

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