Possible brake problem?

[Lamar]

I have a 2012 Fusion Hybrid with 28K miles. About two weeks ago, I started noticing that occasionally when I apply the brakes, I get an electronic chime noise (similar to the one you get when the key is in the ignition with the door open) only much faster that last 1-2 seconds. I cannot feel any difference in the braking and all feels normal. There is no warning light or message on the dash when this happens. It doesn't happen all the time, but seems to happen mainly when the car has been at highway speeds for a while. I would appreciate any ideas on this. I have not taken it to the dealer, yet.

[lolder]

This sounds like a brake system message center alert for which a message should be displayed. Enter Engineering Test Mode ( ETM ) by holding both the "Reset" and "Setup" buttons for at least 5 seconds while turning car on. The first of 10 ETM screens will appear on the right. Cycle through the screens by pushing the "Reset" button to the 10th and last screen to see if any DTCs are displayed. One of the screens also checks all the warning and caution lights but not message center displays. Something should be serviced.

[acdii]

So thats how you get that screen. Had the 2010 for 2 years and never knew that(never needed it, but nice to know).

[Lamar]

Thanks for the info lolder. Coincidentally, later today I finally got a message, after the chime, that said something about "motor overheating". The gas engine temperature is fine, so I guess it has to do with the electric motor. The message came and went so fast I hardly saw it. Anyway, I went to the ETM screen like you said and went through all of them. The last one did not list any DTCs. I guess its time to go to the dealer since I still have a warranty. Thanks again..

[lolder]

Get that fixed right away. It's a separate system from the ICE with it's own reservoir and pump.

[hybridbear]

Thanks for the info lolder. Coincidentally, later today I finally got a message, after the chime, that said something about "motor overheating". The gas engine temperature is fine, so I guess it has to do with the electric motor. The message came and went so fast I hardly saw it. Anyway, I went to the ETM screen like you said and went through all of them. The last one did not list any DTCs. I guess its time to go to the dealer since I still have a warranty. Thanks again..

I would check the coolant resevoir for the hybrid coolant. Perhaps it is low/empty. Since the traction motor does most of the braking, if it's overheating & disabled you would have strange brake performance. Highway driving creates the most heat in the hybrid components on the 2013+ because the stater coils heat up as a function of speed, even when only a small amount of current is being applied to the motor. And the traction motor RPMs are a function of wheel speed, independent of ICE operation.

Edited June 1, 2014 by hybridbear

[Lamar]

Update...FYI...Took my FFH to the dealer. They pulled code P0A01 (not sure what that is because I couldn't find it in my list of DTC codes). They said they found the coolant temp wiring harness rubbing the sub frame, I guess causing a short. Remedy, they repaired the harness and re-routed it away from the frame. Nothing ever was overheating, just the system indicated it was because of the wiring. Make sense?