2022 Mazda 6 not starting lost communication with pcm

Hi guys 
I hope you are doing well

i really need your help 
I’m lost on this one 

Car was starting find
has suspension damage and guard. 
I removed the guard and replaced lower arm. 


I tried to start the car to turn the steering it didn’t I thought maybe the brake sensor off. 

after I put everything back together  , earth cables .. etc the car didn’t start 
ignition of but won’t start 

I called someone mobile mechanic he scanned the car and found these codes. 

I tested fuses all seems okay 
not sure what else.  
please help me 
see attached 

Videos 

Hi again,
Not sure why I can't see the videos, if attached.

Do you have a scanner that you can use again? Newer Mazdas, and other ones, show several misleading errors when the battery is low.

Let's start by saving the codes if there is more, otherwise the ones in photos should be fine. Make sure the battery is fully charged, clear, scan again and report.

Also, can you share some pics of the damage?

You mentioned hearing the throttle noise, that's totally normal.

Hi mate thank u heaps 
irs rh damage 
the thing is the car was working fine no issues at all 

tik I disconnected the earth cables to the damaged guard and removed lower arm I tried to start to turn the steering and it didn’t.  So I thought it was the brake sensor 
Put back everything and it didn’t start 


I charged the battery fully tried jump start 
and the professional he said he couldn’t auto get into the car tcm /ecu not reading 

so he had to force enter by typing the vin and the number on the ecu and that’s what codes we have. 


I’ll share video I think it’s too long to upload. 

It’s doing an exactly like your cx-5 you were mentioning with green push start when you press it goes orange blinking and throttle knocking. 

No problem!

Ignore the amber light blinking in the button. It just indicates that there is a malfunction in the stop/start system or in one or more of the modules it communicates with. Some modules, such as the ABS is Ok to unplug if it's faulty, and will cause the lighting to go amber, but the car should start. The throttle buzzing/knocking is normal; ignore that too.

Before we go into CAN diagnostics, start with a visual inspection of the damaged area and look for any damaged wires. It wouldn't hurt to unplug the ABS as it's the closest to the area.

Try uploading the video to Youtube and include, or take a few pictures of the damage.

Hi nafe
thank you again 
I just uploaded a video on YouTube 
please see the link 


also I disconnect abs and still no good 

please see the video 
I just bought a multimeter too to continue testing 

Also 
I just tested the battery voltage it’s at 11.45 

but before when I charged it 
it was above 12 
maybe coz it’s been sitting for a week 
Just something  to mention I did try jump start and when I plug the jump start I still get 11.45 is that normal ? Or the jump start not working ? 


also originally I fully charged the battery and stil. Didn’t work 

It seems the problem was already there even when the car started fine before. I see 2 places that need to be checked for communication lines.

Any broken wires in this harness?
1.jpg

And here. There should be communication lines there too. I know in previous generations, the junction lines is attached to the washer reservoir as shown in the other pic (circled in red) and the following picture for a better visual
2.jpg
3.jpg
4.jpg

Also, what about the grounds, circled in yellow? Not sure about the newest generation, but they usually connect to a metal bracket under the fender.

You asked about TCM. The module is inside the transmission. It’s easy to disconnect, but it’s required to start the car, so ignore that for now.

The throttle buzzing I was referring to is not what I hear in the video. Is that actually coming from the throttle?

Notice the security/theft light is flashing fast. It’s likely because of the communication issues.


Before you go any further:
1. Carefully inspect the wires. Use the multimeter to check for at least continuity between wires you suspect. Focus on communication lines. They are twisted-pair and should be in red and white (unless they changed the color).
2. What is the battery voltage when it’s fully charged? 11.45 is not enough. Do not use a jump start in the mode to jump it, use it to maintain charge after it’s fully charged to at least 12.4
3. Check for the ground junction I circled in yellow. Does your car have it?

If you don’t have a scanner. I’d recommend FORscan ( forscan.org/home.html ). Free to use for a couple of months and the license is cheap. And get a supported adapter like this:
5.jpg
It will make your life a lot easier.

Hi mate

yes there are some cuts in these cables but I thought they are just sensor plug , headlight and water washer thing. But even if cut or not connected to headlight or sensor the car should work ? Or is that wrong ? 

there is one that has 2 earth which I checked with test light which I’ll show in picture 


the washer bottle is gone as shown in the video 
but the car came from another state was starting fine drone to truck  and off the truck and drove it to my back yard. 


also the cables under fender I explained in video I removed and put on the body as shown two of them they were above each other on fender plate I removed and attached on the body and checked earth going to them 


I’ll charge it tomorrow

so what else goes to that washer bottle and sensor and I think one cable is turbo interloper plug … do they also affect ? 
they were cut off and car was driving. 


 

Also 
regarding that yellow part you circled 
I don’t see it 
see attached a better photo of the wires 

but I had two of the earth they look like 
which I posted before 
they were on the fender and I attached above to the body which they have earth 

I found photos before I touched the car and was running fine 
as shown the only thing was removed these two earth and connected above in my previous post. 

please See attached photos all was before I removed anything and the damaged guard is there. 
 

Ok, sounds like earth wires are in place.

Just because it started before, it does not mean there was nothing wrong with it. When the network is down, all kinds of issues can happen, including intermittent crank/start, etc.

See pics attached about washer bottle. Besides the connector going to the headlight and turbo, there is a junction, circled in orange, that’s attached to the bottle. Not sure if there are communication lines there, but check for damage.

No, if turbo and headlights are not connected, they won’t affect the starting system.

Find the twisted-pair communication wires in the damaged areas and trace them to see where they are broken or shorted. Even if the cars starts now, it’s not fixed. It may take some time, but you will get there. The goal is to get the network up and running with all modules communicating.

Hi 
yeah that could be 
I just want to start the car now and figure out the rest later. 

buf I cannot start it at all now. 


please see attached in red circle 
I think they are what you r referring to 
but what’s weird with test light they are both green which means they give ground .. but not sure if they are the switch/conneccter u r referring to ? 

so where do I need to connect them ? 
They have earth both but where they need to go 
so I assume they give earth don’t take earth ? 


 

Also
What do you mean by twisted line
Which one is that please that I need to follow and see it’s not damaged ?

You don't connect communication lines, they are already connected to modules and to other connectors/junctions. Think of them as network cables connecting computers. If they are damaged, the computers won't be able to communicate. Modern cars rely on communication for a lot of things, including starting.

Look at the picture attached, not from Mazda, but same thing. You can see a pair of twisted wires in yellow and black. You can trace them from the ECU or ABS, as those modules are close by, or check the wiring harness.

I just thought these should go to washer bottle 
but thought they would be plus and minus
bur They are both giving earth so are they supposed to be connected to the washer bottle or somewhere else ?

I’ll chase that cable u showed me I got it now thank u so much 
and I’ll chase the damaged cables and I’ll update u 


 

Hi mate
i chargwd the battery it’s 12.45v and still no luck

regaring cables 
there are two cables I’m not sure where they belong too. 


I can see one to intercooler 
the big one for headlight 
one For sensor 
and I assume one of the others for washer bottle but not sure which one 


please see attached 
these came like that originally.. 

I thought if cut going it headlight it’s okay as no headlight anyway and car should start ? 


the red circles one of them is 2 earth next to earth other not sure where they go 
and the other one no idea as well ? Maybe to the washe bottle which is cut 
 

Charging the battery will just ensure proper diagnosis as there is clearly a problem in the communication lines/modules.

Usually 2 connectors would go to the washer bottle, one for the pump and the other for the low-level fluid sensor.

Correct, if there is no headlight, it should start. But if the wires are shorted, they could cause other issues, especially with adaptive lighting. It does not seem to be the case here.

Your focus should be communication lines, ignore these connectors for now. Look at the picture attached; I circle the junction in yellow. The red white wires you see there should be for communication. They are twisted, just not in the area near the connector/junction. Remove tape from that circled junction and inspect them. Take a couple of pics of exposed wires so I can confirm if they are for communication. Then, trace those wires to the ECM and ABS from end to end, and focus on the areas that look damaged in the wiring harness as I mentioned in the initial posts.

Remember, your focus is communication, you need to find where these red and white wires are broken/shorted. Once you restore communication, the car should start.

Hi mate
fhank you so much for your help again 
I really appreciate it. 
as it’s been driving me crazy. 

I removed the tapes and took some photos. 

there were cuts in that plug which I’m not sure what for 
Cut in the one going to the intercooler 
I joined  them together and still no luck. 


from above it all looks good as well 
I found these twisted cables which they go to that plug they were cut I joined and tested voltage please see pics attached. 


if voltage is different than the battery 
does that mean an issue? 
 

You’re welcome!
It’s a puzzle, with some critical thinking and patience, you will solve it.

Although those are twisted, they don’t look like communication wires. There are other wires that connect sensitive devices, and they twist them to avoid issues with electromagnetic interference.

Ignore those 2 wires going to the intercooler and go back to the ones I mentioned in the previous post. Did you remove the tape in that junction? If so, share pics.

See the pic I attached. I circled where I see them. Again, trace them from that junction all the way to the ECM and wherever they split, such as towards the ABS.

You will measure the voltage in these wires later; for now stick to visual inspection.