“Check Brake System” message while using cruise control

[VelociRap]

Hey guys,
I’ve been having a weird problem, when using cruise control after about 20-30min it displays the “check brake system” message and the brake pedal is hard to press for the first time only, without using cruise control (just completed a 5 hour leg of a road trip) there is no “check brake system” message and the brake pedal feeling is always the same.
I’ve tested this in and out multiple times and in different situations and combinations, including (safe) emergency stopping or towing a trailer and the brakes don’t fade and perform just as they always did.
I used OBD Scanner and there is no code stored, and the message resets after every engine stop.
Any ideas will be appreciated.

 

[Nex]

What is your brake fluid level at? Pads worn?

 

[FordTechOne]

What year is the truck? Generic OBD2 scanners are not capable of reading DTCs from modules other than the PCM, you would need IDS, ForScan, or a professional scan tool to retrieve DTCs. If it has a warning message, there should definitely be DTCs.

 

[smurfslayer]

I’ve been having a weird problem, when using cruise control after about 20-30min it displays the “check brake system” message and the brake pedal is hard to press for the first time only, without using cruise control (just completed a 5 hour leg of a road trip) there is no “check brake system” message and the brake pedal feeling is always the same.
I’ve tested this in and out multiple times and in different situations and combinations, including (safe) emergency stopping or towing a trailer and the brakes don’t fade and perform just as they always did.

So, I don’t want to be the doomsayer but I do want to emphasize to you to NOT underestimate the severity of this problem.

It sounds like something relate to adaptive cruise. Prior to the above post, I did --not-- know that run of the mill scanners wouldn’t pick up DTC’s from other truck modules. Lesson learned. I use FORSCAN anyway but good info.

An unexpected brake failure has the potential to totally ruin your day. In 2008 wife and I rented a bmw r1200rt out of Munich. We were a couple days into a trip heading over Susten pass down into the town of Andermatt. Approaching a hairpin the bikes abs module faulted, lever and pedal gone - as in zero braking left. Nothing. We’re going 50? ish. I downshifted to first. It was not a graceful downshift and redlined+ the engine, but it slowed us enough to make the turn, coast into pull off a couple hairpins later. Like you describe, the fault reset after an ignition cycle leading to a false sense of security i would say. I tip-toed the bike down the mountain, made all the way off the mountain and it faulted again. Each time, as the brake system faulted, it was a while with zero brakes, then, the fault would set and brake power would be restored. If you’re still holding the lever, suddenly you have full braking power, meaning you lock up the wheels or wheel depending. To me it felt like about 5 seconds in this no brakes state, but in reality it was probably under a second.

My point is, take it seriously and good luck with the repair.

 

[905_Raptor]

Perhaps a vacuum related issue associated with the cruise control system that is detected by the brake assist system.

As smurfslayer said, don't wait to resolve this.

 

[VelociRap]

What is your brake fluid level at? Pads worn?

New pads, about 3k miles - 5months, will check fluid later today.

 

[VelociRap]

What year is the truck? Generic OBD2 scanners are not capable of reading DTCs from modules other than the PCM, you would need IDS, ForScan, or a professional scan tool to retrieve DTCs. If it has a warning message, there should definitely be DTCs.

Thanks! Will take it to the dealer so they can run diagnostics.

 

[washumin]

Did you resolve this. I have the exact same issue. I took my first road trip with cruise control. 20 min in it pops up. I feel its vacuum related. Any input would be helpful.

 

[Nex]

Did you resolve this. I have the exact same issue. I took my first road trip with cruise control. 20 min in it pops up. I feel its vacuum related. Any input would be helpful.

First post I see, Welcome to FRF.

Need more information on your truck. Year, miles, speed while driving, road conditions, what codes did you pull?

 

[fur_pig]

I had this, Iwe leaking vacuum. Hub and Iwe replaced and issue fixed