2021 CX-5 GT Smart Brake and Forward City Brake errors

[lazygun247]

Appreciate the help on this matter below and I'm kind of at a loss for what is going on. I've been trying to diagnose this for the last 2 months and I think I have finally been able to reproduce the issue, but no idea what is the cause.

The following errors popup:
- Smart Brake System Malfunction
- Forward City Brake Support Malfunction

This is reproducible if I turn the lights to Auto and just wait. I can speed the process up by having the lights on auto and turning on the heat, heated seats and/or steering wheel, or using the cigarette burner. Basically anything else that I turn on to suck more energy out of the car, the quicker the errors come on. I can be sitting still and these two errors will come out.

Errors will not come out if I do not have the lights to auto.

So the diagnostic things I have done:
- Brake switch/stop lamp change. Exchanged twice... still same issue.
- Changed 12V battery. I have noticed that the battery is at 12.7, but as soon as I plug into the car, it drops to 12.4 (wondering if there is a load on it, even when the car is off)
- Checked the brakes. All the brake pads were recently changed (prior to purchase actually) with good wear. Everything sliding well and without issue.
- Battery will drain over the course of 2 days from 12.5 resting to 11.9 resting.

Other notes:
- Errors initially started on a trip. No car wash. Not after rain.
- Engine throttles a little bit (like going into sport mode) when the errors are on, but otherwise no issues with braking, parking brake or any function.


Appreciate any insight.

thanks

 

[N7turbo]

Battery will drain over the course of 2 days from 12.5 resting to 11.9 resting.

This is concerning and should only be happening with a parasitic drain or a bad battery.

Please list any and all accessories plugged into the car.

 

[lazygun247]

This is concerning and should only be happening with a parasitic drain or a bad battery.

Please list any and all accessories plugged into the car.

I had a dashcam plugged into the 12v cig. I have noticed that if I unplugged the dashcam, it will take longer to cause the error. However, it still does happen. I've changed the battery twice and now and usually when i plug in the new battery, there is no issue and everything will work great for like 20 miles and then issues come back again, which supports some kind of excessive power drain.

The only other thing plugged in is an iPhone cable to the center console which is not plugged into anything

 

[lazygun247]

Should also note that there are no recalls currently on my VIN per mazda

 

[HyFlyer]

I'd say the two errors you see are just symptoms (low voltage) of the real problem (parasitic draw).

 

[lazygun247]

I'd say the two errors you see are just symptoms (low voltage) of the real problem (parasitic draw).

I don't disagree, but kinda wondering what I can do about it other than go to the dealer?
The draw doesn't exist when I don't turn on the auto lights though which is what is weird to me.

 

[HyFlyer]

So, if you have your lights in anything but "auto" there's no problems?

 

[lazygun247]

So, if you have your lights in anything but "auto" there's no problems?

Actually, its pretty much anything other than off for my lights I think, but I notice most often on the auto. My lights have the adaptive movement where it moves with side to side when you have it on.

Should note that whenever the lights are on off position, the lights still come on, but there is no adaptive swiveling over the lights nor high beam.

 

[HyFlyer]

hmmmmm, IIRC, I've seen a post or two about issues with the little motors that control the adaptive light swivel failing. I recall they talked of being able to hear a "buzzing" noise coming from them.

 

[lazygun247]

hmmmmm, IIRC, I've seen a post or two about issues with the little motors that control the adaptive light swivel failing. I recall they talked of being able to hear a "buzzing" noise coming from them.

Right now, I'm not sure if its the motors or lights themselves. There's not much humming that I can hear coming from the motors. They are like dead. Kinda out of ideas of what to test.
After a few months, finally able to isolate it to this area though. Think next steps is the dealer

 

[stickerbush]

I don't disagree, but kinda wondering what I can do about it other than go to the dealer?
The draw doesn't exist when I don't turn on the auto lights though which is what is weird to me.

How do you know the draw doesn't exist with auto-lights off? I believe you said that with the car sitting the battery voltage goes down under 12v.

One thing you could do would be to have your charging system tested. Many places that sell batteries will test your charging system free of charge. A bad diode in the charging system could be responsible for the parasitic draw and a low charging voltage while driving.

You could also get something like https://www.amazon.com/dp/ (commissions earned) that will plug in to a 12v lighter socket and allow you to monitor voltage while driving.

 

[lazygun247]

How do you know the draw doesn't exist with auto-lights off? I believe you said that with the car sitting the battery voltage goes down under 12v.

One thing you could do would be to have your charging system tested. Many places that sell batteries will test your charging system free of charge. A bad diode in the charging system could be responsible for the parasitic draw and a low charging voltage while driving.

You could also get something like https://www.amazon.com/dp/ (commissions earned) that will plug in to a 12v lighter socket and allow you to monitor voltage while driving.

It may be happening, but it isn't happening so much that it causes a low voltage error. Driven now multiple days with auto-lights off (or actually just lights on the off section) without any significant issues.

I thought it was the light socket at first, but we just unplugged it so it isn't drawing anything right now. The error just comes if we drive with the auto lights on after a while (depends on the charge when you do it I guess). Like if battery is fully charged when we turn it on, it wont be an issue for like an hour, but if it was after a week or so of not driving and the resting voltage is low, it'll come on pretty quickly

 

[Gus75]

Appreciate the help on this matter below and I'm kind of at a loss for what is going on. I've been trying to diagnose this for the last 2 months and I think I have finally been able to reproduce the issue, but no idea what is the cause.

The following errors popup:
- Smart Brake System Malfunction
- Forward City Brake Support Malfunction

This is reproducible if I turn the lights to Auto and just wait. I can speed the process up by having the lights on auto and turning on the heat, heated seats and/or steering wheel, or using the cigarette burner. Basically anything else that I turn on to suck more energy out of the car, the quicker the errors come on. I can be sitting still and these two errors will come out.

Errors will not come out if I do not have the lights to auto.

So the diagnostic things I have done:
- Brake switch/stop lamp change. Exchanged twice... still same issue.
- Changed 12V battery. I have noticed that the battery is at 12.7, but as soon as I plug into the car, it drops to 12.4 (wondering if there is a load on it, even when the car is off)
- Checked the brakes. All the brake pads were recently changed (prior to purchase actually) with good wear. Everything sliding well and without issue.
- Battery will drain over the course of 2 days from 12.5 resting to 11.9 resting.

Other notes:
- Errors initially started on a trip. No car wash. Not after rain.
- Engine throttles a little bit (like going into sport mode) when the errors are on, but otherwise no issues with braking, parking brake or any function.


Appreciate any insight.

thanks

Read my comments from today on brakes. You may have damaged the brake retracting screw as the car may not have been placed in Service Mode first. The caliper piston have to be retracted before inserting new pads. To retract piston, a scan tool is used to retract them. Not all Mazda years and models use same procedure to put car into Service Mode for brake job. Start by examining the calipers and pistons. If your mechanic just pushed the pistons back by squeezing the pistons back manually, then he may have damaged the 'screw' that winds/screws back and forth to drive the calipers piston.

Model year 2022.5 service procedure for Service Mode may differ from older model years. Hence special scan tool required for brake job from what I have been lead to believe for 2022.5+ cx-5 model years.

 

[N7turbo]

A tool is not needed for maintenance mode.

 

[Gus75]

A tool is not needed for maintenance mode.

What is the new procedure to cx5 2022.5 + into Maintenance Mode? The ones used on 2018 etc does not work on this new model from what people are saying and showing on utube.