“Check Brake System” comes on after repair on 2011 Lincoln MKZ hybrid, 67K Miles.

The “Check Brake System” comes on intermittently for the past several months. Dealer replaced the brake control, module, and hose for $3,000 (diagnostic code on invoice was B1634). Three weeks later, “Check Brake System” light is came on again (before the fix, I had gone up to a week between light coming on).
I take it back, they do the diagnosis and say it is due to a completely distinct issue - now I need to replace the brake vacuum/booster (code C1015:64). It’s strange I am having multiple parts fail all giving “check brake system” over a short span of time on a car with only 67k miles. I question if the root cause of my car’s problem has actually been identified . Are the codes a reliable way to diagnosis my car’s problem? Is there something that could be failing/malfunctioning that would create issues in these different brake system parts? Or is it really just bad luck? I have noticed no difference in how my car drives.
Thank you for any insight you can provide,
Kelli

Ok, the first trouble code B1634 is a body error telling the right mirror adjustment motor is bad, not a brake code. A brake code would be a C code. The C1015:64 is a vacuum supply problem. Faulty vacuum sensor or vacuum pump. I would think replacing the sensor, not the booster would be the solution.

Error codes are a guide in a diagnostic troubleshooting process, NOT, a “replace this part” instruction. So, no, the dealer has not found the core problem(s). I think you should have the service writer, or the service manager explain why you paid $3000 for a mirror code and why they think swapping the booster will fix a sensor problem. The answer or lack of one will determine if you should change dealers.

I suspect they are guessing and changing parts rather than actually diagnosing the problem(s). The flip side is a hybrid is a complicated car that is expensive to repair.

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