ECU bypass cable instructions for 2019/20s & AlfaOBD

[John Jensen]

A bypass cable was not needed for my 2016 so this is new to me.

I ordered a bypass cable/harness from kaodtech (a great harness maker) for my forthcoming 2020 3500.
The instructions say: "The harness needs to be removed before returning your truck to a dealer for service." But they don't say why.

I'm not sure if I want to install it as "temporary" or "permanent". I'm leaning to permanent but wonder why the instructions say what they say. Would the dealer techs have problems hooking up or using their software or testers?

Does anyone know or have advice?

 

[OCDTech]

I would imagine the dealer has their own device or their scanner bypasses it already. This being said they can be picky with warranty claims sometimes. Don't want people modding or changing things. They don't care about the BCM probably even they could even know. But the port is a link to the ECM which they definitely don't want you tuning.

 

[Ricks Ram]

A bypass cable was not needed for my 2016 so this is new to me.

I ordered a bypass cable/harness from kaodtech (a great harness maker) for my forthcoming 2020 3500.
The instructions say: "The harness needs to be removed before returning your truck to a dealer for service." But they don't say why.

I'm not sure if I want to install it as "temporary" or "permanent". I'm leaning to permanent but wonder why the instructions say what they say. Would the dealer techs have problems hooking up or using their software or testers?

Does anyone know or have advice?

They suggest removing it in case the dealer notices it and has a problem with it when your under warranty.The harness itself is pretty much invisible once installed. It literally takes around ten minutes to install or remove so it's really not a big deal either way.

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[John Jensen]

I hear what both of you are saying. That if left in place it could alert the dealer and possible affect the warranty.

If you disconnect it it is still visible hanging around. That would be the same alert factor as if it were in place.

I'm not yet buying that as the reason. Maybe kaodtech can tell us why he makes that statement in the instructions. If he doesn't chime in I will PM him.

 

[1500ram12]

Probably just a "I'm not at fault" statement if you get denied a warranty claim because of his harness.

As stated above, dealers can be picky on warranty issue's if a aftermarket part is installed. They could claim that this bypass harness is similar to a tuner.


2018 2500 6.4L Hemi Tradesman

 

[Dodge 1500 4X4]

I also bought the same Bypass cable my concerns are as yours, I would like to install the cable permanent, but as stated here the dealer may detect the bypass or the OBD bypass connector might not connect to there software, who knows, I don't want to be denied a claim on Warrantee, I'm going to install mine and see how it goes, the Can blocks are behind the headlight switch that may have to be removed, hope more will chime in for any other thoughts or ideas, also KAOdTECh has a few warnings to do at your own risk.

 

[1500ram12]

You can always disconnect the obd2 T and place the original obd2 back in place and tuck the T up out of the way if you need to go to the dealer. Unless you are going in for something that would require them to be up under the dash they'd never know it's there.


2018 2500 6.4L Hemi Tradesman

 

[John Jensen]

Probably just a "I'm not at fault" statement if you get denied a warranty claim because of his harness.

That makes the most sense - a liability issue. If it turns out that it is the only reason I'm going with the permanent install. My great Service Manager knows I have my 2016 tuned (he supports it) and that I modify with AlfaOBD I'm not worried about "alerting" the dealer.

 

[John Jensen]

The harness itself is pretty much invisible once installed. It literally takes around ten minutes to install or remove so it's really not a big deal either way.
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Rick,
When you say "ten minutes to install or remove" do you mean entirely removing it or just removing/replacing at the OBD2 plug?

If entirely wouldn't better to make a temporary install and keep it tucked away until you need it?

 

[1500ram12]

Rick,
When you say "ten minutes to install or remove" do you mean entirely removing it or just removing/replacing at the OBD2 plug?

If entirely wouldn't better to make a temporary install and keep it tucked away until you need it?

If you are flexible then yeah it can be done in 10. Took me about 15 minutes to install it. The can ports aren't in the best location.

Since the cable bypasses the security module, it's definitely a liability statement. So along with possible warranty denial, if someone hacked your vehicle he wouldn't be at fault.


2018 2500 6.4L Hemi Tradesman

 

[Ricks Ram]

Rick,
When you say "ten minutes to install or remove" do you mean entirely removing it or just removing/replacing at the OBD2 plug?

If entirely wouldn't better to make a temporary install and keep it tucked away until you need it?

No it only takes ten minutes to completely remove or install. I guess it might take you a little longer the first time you install it because your not familiar with it but once you are it's pretty basic. It's just a matter if taking two screws out of your knee bolster and popping it off and then popping out your OBD port and then popping in the new one and then plugging it all in. . My truck is a 14 but I actually ordered one with connectors for both the 1500 and 2500/3500 trucks because I work on so many years and models. I use it all the time. I enable the codes and then remove the harness. I reccomend keeping it installed until you are pretty sure you have enabled everything you want and then remove it completely or just disconnect it and tuck it out of the way if you need to take your truck in for warranty work. There is no reason to give the dealer anything they can use as an excuse to deny warranty work or use it as an excuse as to why their inept mechanics can't figure out whats wrong with your truck.

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[John Jensen]

Rick,
Thanks, You make sense.
When you mention "inept mechanics" that triggers a bell. I certainly wouldn't want one of those guys to wonder what the harness is and tear it out or damaging it in some way. That's enough reason to not leave it in place.

I'm for sure back to installing it in the temporary mode.

 

[Dapk]

If you go to the dealership and you have bypass in and the dealer uses their bypass as well. It will cause issues.
Been down that road on troubleshooting already.

 

[JCAP]

A bypass cable was not needed for my 2016 so this is new to me.

I ordered a bypass cable/harness from kaodtech (a great harness maker) for my forthcoming 2020 3500.
The instructions say: "The harness needs to be removed before returning your truck to a dealer for service." But they don't say why.

I'm not sure if I want to install it as "temporary" or "permanent". I'm leaning to permanent but wonder why the instructions say what they say. Would the dealer techs have problems hooking up or using their software or testers?

Does anyone know or have advice?

The dealer uses a tool called the WiTech Micropod 2. If that device does not see the Security Gateway Device (SGW) because of an installed bypass cable, it will not communicate with the other ECU's in the vehicle. Look at the attached graphics. The graphic with the blue icons is a properly functioning SGW. The graphic with the red icons is what the dealer would see with if the SGW is not responding.

 

[John Jensen]

If you go to the dealership and you have bypass in and the dealer uses their bypass as well. It will cause issues.
Been down that road on troubleshooting already.

Thanks. I had my suspicions, you are the only one to confirm it. Much appreciated

 

[John Jensen]

The dealer uses a tool called the WiTech Micropod 2. If that device does not see the Security Gateway Device (SGW) because of an installed bypass cable, it will not communicate with the other ECU's in the vehicle. Look at the attached graphics. The graphic with the blue icons is a properly functioning SGW. The graphic with the red icons is what the dealer would see with if the SGW is not responding.

View attachment 201594 View attachment 201595

Thanks JCAP.
I said Dapk was the only one to confirm it and it turns out that I was wrong. Your post was not up when I posted that.

I appreciate your confirmation as it has proof.

 

[Dapk]

There are also buss issues on unlocked ecu's for tuning. They are intermittent through which makes tracking things down more difficult. Dash will read "no buss" at times.

 

[Dodge 1500 4X4]

Has anyone here installed this bypass cable, the OBD isn't hard, but getting to the
Can Blocks behind the headlight switch to connect the green and white connectors, how do I remove the headlight switch.

 

[Ricks Ram]

[QUOTE="Dodge 1500 4X4, post:
Edit

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[Jimmy07]

Thanks JCAP.
I said Dapk was the only one to confirm it and it turns out that I was wrong. Your post was not up when I posted that.

I appreciate your confirmation as it has proof.

Just to explain further why the bypass can’t be left connected- like explained above, when the dealer plug the wiTECH in, it’s looking to unlock the security gateway, and run all of it’s diagnostics through it. If you look at the male connector of your bypass, you’ll see there’s only three wires inserted into it- one battery power and two grounds, and those get passed onto the new female connector on the bypass harness. This is what’s needed to power your OBD device. Then, from the female connector on the bypass harness, the two twisted pairs go straight to the two can junction blocks the red arrows are pointing to, effectively bypassing the gateway.

Since those twisted pairs don’t pass through into the male bypass harness connector, you have effectively cut out those same two can bus pairs that the green line is drawn through, cutting out the gateway module. If the bypass is left installed, the only thing the dealer wiTECH knows to look for is that gateway to unlock, and it doesn’t know/recognize that it’s actually plugged directly into both can blocks.