Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

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SkewedView

Member
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2014 CX-5
Please! I need help from someone smarter than me!

I recently purchased a 2014 CX-5 Grand Touring with 60K miles on it. All of the scheduled maintenance has been completed on time.

Recently the car has developed a intermittent problem where it scrolls through multiple problems at the same time, which include:

SCBS INSPECTION REQUIRED
ENGINE INSPECTION REQUIRED
TPMS INSPECTION REQUIRED
BRAKE OVERRIDE SYSTEM INSPECTION REQUIRED

The check engine, TPMS, and SCBS lights are illuminated while the messages scroll.

Sometimes the engine would bog down as if it had a dirty fuel filter.

When all of the problems are displayed the brake likes don't work when the headlights are on.

I hooked up a meter and downloaded a single code:

P0571 BRAKE SWITCH A CIRCUIT

The faults and warning lights will come on and stay on for different lengths of time and then disappear for different lengths of time for no apparent reason. There is no difference in the way that the car drives with or without the warnings, except that the cruise control will not engage.

I have replaced the brake switch, but I still have the same problem.

I have a trailer lights installed.

Any ideas? There are no Chilton or Haynes manuals for this car. I don't know where to start without paying a dealership a ton of money.

Thank you!
 
Last edited:
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

SkewedView said:
⋯ I hooked up a meter and downloaded a single code:

P0571 BRAKE SWITCH A CIRCUIT
Click to expand...
Was your 2015 CX-5 a CPO purchase, or do you have any other warranty coverage?

You can also go to Auto Zoze getting a free error code readout with the suggestions of how to fix the problem.

Since you do have a code P0571 indicating brake switch problem, you should go ahead replace the brake switch on the brake pedal mechanism as I seem to remember there's a TSB for the brake switch and a bad brake switch would cause all kind of weird and unrelated problems like yours. Search the forum for related thread.
 
The car is a 2014, purchased by a family member back in 2013.

There isn't anymore warranty coverage.

The code is for BRAKE SWITCH A CIRCUIT. I did replace the brake switch (I failed to mention that with the original post, but have since edited it). Still the same problems. I wonder if I should clean the contacts on the actual speed sensors on each wheel, or replace the sensors.

Thanks for your input!
 
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

SkewedView said:
The car is a 2014, purchased by a family member back in 2013.

There isn't anymore warranty coverage.

The code is for BRAKE SWITCH A CIRCUIT. I did replace the brake switch (I failed to mention that with the original post, but have since edited it). Still the same problems. I wonder if I should clean the contacts on the actual speed sensors on each wheel, or replace the sensors.

Thanks for your input!
Click to expand...
There're several threads listed here which look like your problem with P0571 code and all had a bad brake light switch. Even if you're sure your new brake switch is with good quality (I'd get an OEM brake light switch), I'd still measure it with ohm meter and compare with the original brake switch making sure it's working properly.

Clear the code and wait the CEL back on again and go to Auto Zone to have them pull the code and print a report with possible solutions.

Of course the next step is checking and cleaning the ABS speed sensors.

You problem is intermittent and it adds difficulty to diagnose the problem.

TCS light and TPMS light coming on!!!!

Clearing Codes.

CEL and Code P0571 ("Brake Switch A Circuit")
 
I think there are two different brake switches, try replacing the other one. The brake switches control lights, cruise, transmission, start system, safety brake systems etc. Check the maintenance reminders in the touch screen, some of the messages may come from that.
 
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

GAXIBM said:
I think there are two different brake switches, try replacing the other one. The brake switches control lights, cruise, transmission, start system, safety brake systems etc. Check the maintenance reminders in the touch screen, some of the messages may come from that.
Click to expand...
There's only one brake light switch but it has 3 prones on wiring connection.

SWITCH, STOP - LAMP
P/N: BN7N-66-490
$_1.JPG

1K001V1.jpg
 
Problem solved!

Replaced the brake light switch -- didn't help.

Disconnected the trailer light harness and returned the tail lights back to factory condition -- didn't help.

With my son pushing the brake I noticed that the brake lights worked fine with the headlights off, but with the headlights on there was barely any noticeable increase in light when the brakes were applied. After scratching my head for a minute I realized that the tail lights that I thought that I was seeing with the headlights turned on were as bright as the brake lights with the headlights turned off. I was seeing brake lights on rather than tail lights.

What is even stranger is that I plugged in my meter to check to see if any codes had popped up. I had the P-0571 code again. I turned off the car to clear the code. With the car off, my meter said that I needed to turn off my car. It still thought that the car was on. I told my son to start the car. He is a brand new driver and accidentally hit the start switch without pushing the brake. The car started right up without the brake. WTF?!

So cut to the chase... I pulled out both tail light bulbs. One was slightly dark and had one of its filaments bent and touching the other one. It must have been intermittently shorting out and freaking out the computer. I replaced it and now everything has been running perfect for about the past three hours of driving. The meter wasn't lying about it being on a brake switch circuit.
 
This is a classic example of a code being misinterpreted due to lack of proper diagnostics. Shade tree mechanics (and most of us fall into that class to one degree or another) pull a code containing the term "brake switch" and they assume the problem must be that specific part. When in reality it could be any number of issues in the switch circuit. Replacing parts based on incomplete knowledge can be an awfully expensive way to spend your weekend. You were lucky you happened to stumble over the cause without too much financial carnage.
 
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

SkewedView said:
Replaced the brake light switch -- didn't help.
⋯
So cut to the chase... I pulled out both tail light bulbs. One was slightly dark and had one of its filaments bent and touching the other one. It must have been intermittently shorting out and freaking out the computer. I replaced it and now everything has been running perfect for about the past three hours of driving. The meter wasn't lying about it being on a brake switch circuit.
Click to expand...
This has to be one of the weirdest story I've ever heard - a short on brake light bulb triggered the error code on brake switch A circuit and all the problems! Kudos to you finding the culprit of you problem with your persistency and also really appreciated your update to the problem!
 
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

paris1 said:
This is a classic example of a code being misinterpreted due to lack of proper diagnostics. Shade tree mechanics (and most of us fall into that class to one degree or another) pull a code containing the term "brake switch" and they assume the problem must be that specific part. When in reality it could be any number of issues in the switch circuit. Replacing parts based on incomplete knowledge can be an awfully expensive way to spend your weekend. You were lucky you happened to stumble over the cause without too much financial carnage.
Click to expand...
In OP's case brake light switch on CX-5 does fail based on many posts found here. Replacing the brake light switch, which is not expensive and costs less than $20 for an OEM, is a proper step to resolve the issue. The probability of the internal filament shortage on a dual-filament 7443 bulb is almost unlikely from Japanese Stanley and that's the last thing I'd suspect. Of course one could measure the original brake light switch with a simple ohm meter finding out if it's good at first. Nevertheless OP's original brake light switch should be good to be saved as a spare.
 
yrwei52 said:
In OP's case brake light switch on CX-5 does fail based on many posts found here. Replacing the brake light switch, which is not expensive and costs less than $20 for an OEM, is a proper step to resolve the issue. The probability of the internal filament shortage on a dual-filament 7443 bulb is almost unlikely from Japanese Stanley and that's the last thing I'd suspect. Of course one could measure the original brake light switch with a simple ohm meter finding out if it's good at first. Nevertheless OP's original brake light switch should be good to be saved as a spare.
Click to expand...
As I said, it worked out Ok in this case, but what if the part (or parts!) replaced had cost significantly more that $20 and was not returnable for one reason (electrical) or another.
 
Please Help! 2014 CX-5 With Multiple Scrolling Faults and P-0571 Code

paris1 said:
As I said, it worked out Ok in this case, but what if the part (or parts!) replaced had cost significantly more that $20 and was not returnable for one reason (electrical) or another.
Click to expand...
Yeah, if the suspected part is significantly more expensive then we would handle the thing differently. For example if my LED Signature accent srrips started flickering and I'm out of the warranty, I would simply leave it alone without fixing it. Luckily for OP the part is cheap, and he traced issue correctly and found the source of the problem! As I mentioned earlier I'd suspect light bulb the last as those kind of thing would never happen in my book. I give the OP full credit suspecting a short on the filaments and found where the real problem was!
 
SkewedView said:
Replaced the brake light switch -- didn't help.

Disconnected the trailer light harness and returned the tail lights back to factory condition -- didn't help.

With my son pushing the brake I noticed that the brake lights worked fine with the headlights off, but with the headlights on there was barely any noticeable increase in light when the brakes were applied. After scratching my head for a minute I realized that the tail lights that I thought that I was seeing with the headlights turned on were as bright as the brake lights with the headlights turned off. I was seeing brake lights on rather than tail lights.

What is even stranger is that I plugged in my meter to check to see if any codes had popped up. I had the P-0571 code again. I turned off the car to clear the code. With the car off, my meter said that I needed to turn off my car. It still thought that the car was on. I told my son to start the car. He is a brand new driver and accidentally hit the start switch without pushing the brake. The car started right up without the brake. WTF?!

So cut to the chase... I pulled out both tail light bulbs. One was slightly dark and had one of its filaments bent and touching the other one. It must have been intermittently shorting out and freaking out the computer. I replaced it and now everything has been running perfect for about the past three hours of driving. The meter wasn't lying about it being on a brake switch circuit.
Click to expand...

A faulty brake light bulb defeated the brake/starter safety interlock and allowed the car to start without the brake pedal being depressed? That's some poor design on Mazda's part.
 
Had the rear lights been changed to LED? If so, perhaps that's when the damage was done...
 
I had a minivan once that used to stall all the time, problem was a bad ground on the instrument panel circuit board. Diagnostics always pointed to something else. Weird electronic problems point to weird resolutions. Good find OP, and yeah, I probably would’ve started with the brake light switch…I have one laying around as a spare anyway.
 
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