Mazda CX-5 experiencing issues after rear brake replacement

I replaced the brakes on a Mazda CX-5 (with an electric parking brake). Unfortunately, I retracted the piston, but it should have been pushed in. I then disassembled the saddle and repaired the mechanism.

Unfortunately, when the parking brake is engaged 10 times, the right brake sometimes fails to release 1-2 times when the ignition is on and the engine is off. If the engine is running and the car is moving, the problem is even worse.

I've now installed a used saddle, but the problem is still the same.

When you engage and disengage the parking brake, the right motor seems to start with a slight delay. I've also tried swapping the motors from right to left, but that doesn't make a difference either.

I don't know what else to do. I already suspected that replacing the brake caliper wouldn't fix the problem, and now I'm sure of it. Even though it was a used saddle, it's unlikely that two saddles would have the same problem.

Hi,

Does the engine not even start when you release the brake?
In this case, I would check the plugs/cables leading to the motor.

Is the fault memory of the corresponding control unit empty?

Best regards, Rainer.

So, if it's not working, apparently the right motor isn't being activated; it's just staying engaged. As far as I can remember, it's also visible in the measurement data from the EFB control unit (but it's been about a month since I did that).

Before I replaced the brakes, I tried to access the service mode using a diagnostic tool (which didn't work, so I had to do it manually using key combinations), and the following errors were stored:

EPB (Electric Parking Brake) 2
Problems exist.
1.C1128:2A-08 Coupling/Uncoupling Switch - Continuous Memory DTC.
2.U3000:53-8B Control Module - Continuous Memory Diagnostic Trouble Code.

After I replaced the brake and it still didn't work, these errors were stored.

C1128:2A-08 Connecting and disconnecting switch.

Failure Type - 2a
Hangs in the area.
Statue Type - 08
(Not current DTC) The error occurred previously.
recognized, but the monitor has the status...
not yet determined.

Continuous.
Memory DTC -

U3000:53-8B Control Unit.

Failure Type - 53
Disabled.
Statue Type - 8b
(Current DTC warning light is on) There is a fault.
currently on, warning light illuminated (MIL).
Wrench, communication center.
etc.).

Continuous.
Memory DTC -





C2005:74-48 Right-hand actuator.

Failure Type - 74
The actuator is slipping.
Statue Type - 48
Error environment data - Mode 12.

Continuous.
Memory DTC -

C112A:77-8B Actuator release.

Failure Type - 77
Destination unreachable.
Statue Type - 8b
(Current DTC warning light is on) There is a fault.
currently on, warning light illuminated (MIL).
Wrench, communication center.
etc.).

Yesterday, I didn't access the error memory at all.

Hello,

At VAG, the end positions are detected based on the motor's current consumption (a steeper increase in current indicates an end position).

The error message you're seeing looks like it's coming from an extra sensor, likely installed in the brake caliper or the motor.
I suspect there's a cable or connector issue with the wires leading to this switch. Because if the saddle was replaced, it would have had to be a new one.
And if the control unit doesn't know whether the brake is engaged or disengaged, it seems to prefer to do nothing at all. X

Best regards, Rainer.

I had the old saddle disassembled, and there's no switch on it. It must be located inside the motor. This one is different now, although it's used.
The measurement data also shows the amperage per motor, so I think it's similar to how it works with VAG vehicles.

Edit: I also swapped the engines around, changing their orientation. And Fehler stayed on the right.

Hi,

Quote:

And if the control unit doesn't know whether the brake is engaged or disengaged, it seems to prefer to do nothing at all.

Perhaps a basic adjustment is needed.
hg
Herbert.

Hi,

chli1976 wrote:

Before I replaced the brakes, I tried to access the service mode using the tester (which didn't work, so I then did it manually via... Keyboard shortcuts created)

Do you mean that it went into maintenance mode without a tester, i.e., with the ignition on, the accelerator pedal fully depressed and held down, and the EPB switch held in the 'release' position?
and turn the ignition on/off 3 times"?

I asked someone from my village who also works on a 2017 CX5. He said that before working on the electrical system... "When the parking brake is engaged, is it absolutely necessary that one..."
This puts them into maintenance mode/service position, meaning the motors retract, which is then the default position!

Assuming everything is mechanically sound, including the used saddle, it might be helpful in your case (if you haven't already done so) to manually put the maintenance mode into effect as described above.
To activate the described function, wait a moment and then deactivate the maintenance mode again (the same procedure, but hold the EPB switch in the 'engage' position).

Best regards, Richard.

Quote:

it is absolutely necessary that one... This puts them into maintenance mode/service position, meaning the motors retract, which is then the default position!

Actually, VW does it this way too...
Perhaps the equipment is out of sync due to the mechanical reset.
hg
Herbert.

E30_V8 wrote:

Hello, Do you mean that it went into maintenance mode without a tester, i.e., with the ignition on, the accelerator pedal fully depressed and held down, and the EPB switch held in the 'release' position? and turn the ignition on/off 3 times"? I asked someone from my village who also works on a 2017 CX5. He said that before working on the electrical system... "When the parking brake is engaged, is it absolutely necessary that one..." This puts them into maintenance mode/service position, meaning the motors retract, which is then the default position! Assuming everything is mechanically sound, including the used saddle, it might be helpful in your case (if you haven't already done so) to manually put the maintenance mode into effect as described above. To activate the described function, wait a moment and then deactivate the maintenance mode again (the same procedure, but hold the EPB switch in the 'engage' position). Best regards, Richard.

The tester lacked a reset function.
That's why I did it using the method you described.
Turn the ignition on, fully depress the accelerator pedal, and either pull or press the handbrake button, then repeat the ignition cycle three times.

I didn't hear the engines running like you do with VAG vehicles either.

On Friday, I'll get the car back. I'm going to swap the cables from the motors, so if the problem is still on the left side (using a cable from the right side), then it's not the saddle.

What's strange is that when the engine doesn't start, it usually works fine. However, if the engine is running and you drive a few meters, the right-hand side [of something, presumably a door or panel] often stops working.

Is there a specific procedure for this?

I've found something for the next model, but for my current model, I could only find the standard mechanical parking brake.

When in maintenance mode, after "Completion of maintenance mode," initiate the automatic release of the electric parking brake.

What does "normal deactivation of maintenance mode" refer to?

I also found instructions on how to fix all those errors and recover the saved data.