What happens if the electronic emergency brake fails? | Car Doctor
Q: My 2021 Subaru Forester has an electronic emergency brake. What happens if the auto electric system fails and the brakes are not working? How do I stop the car? I have asked the dealership and the manufacturer with zero response.
A: The electric parking brake is basically an electric motor that pulls up on the parking brake cable. You would need to have a total failure of the electrical system — as well as the battery completely discharged — for the parking brake to not work.
As you have probably noticed, the car doesn't need to be running for the parking brake to work. The term "emergency brake" is replaced with "parking brake."
Today, we don't think of the parking brake as something to use if you have no brakes. It is designed to keep the car in place when parking. For more than 50 years, cars have had dual-hydraulic brake systems, and the chance of completely losing the entire braking system is very unlikely.
Q: I have a 2019 Volvo XC40 with a problem that has been present since I took delivery. When I start the car, the engine has a rough idle for about a minute. During this time, the RPMs measure about 1,500. Once the idle settles down at 900, it's relatively smooth but not perfect.
The car has been to two different dealerships, and both tell me it’s normal. This problem happens regardless of time of year, exterior temperature, or whether the car is cold or warm.
My friend has the same year and model car, and his does not do this. I find it hard to believe that the idle issue in my car is normal.
I’d welcome your feedback and suggestions. My warranty expires in March 2023, so I’d like to get this resolved before then. Could it simply be a spark plug issue?
A: There are no technical service bulletins that I am aware of (at least in the databases to which I have access).
The best way to determine the problem is by demonstrating it to a Volvo technician or Volvo field engineer. Every engine has some level of vibration, and Volvo may consider your car within an acceptable range. Ideally, compare your car to the exact model to see how they perform.
If I had to just guess, I would say there is a very slight air leak — once the car runs, the computer system compensates. The most common problem with this engine is a leaking emission purge control valve, which is certainly worth looking into.
Q: I have two cars, a new Subaru and a older Nissan Maxima. There is a long downhill near our home, so instead of breaking, I downshift my Subaru and have to shift down three or four gears before the car does not accelerate downhill. With my Nissan, I need only put it in manual shift, and it stays at a steady speed, not needing to downshift at all. Why do these two cars act so differently? I have an idea, but you may have a better one.
A: The two cars use two very different types of transmissions. The Nissan uses a conventional automatic transmission with actual gears. When put in manual mode, the gearing uses engine braking to slow the car down.
The Subaru uses a CVT (continually variable transmission) that uses no gears and behaves differently.
Although Subaru, as well as other manufacturers who use CVT transmissions, can give you a manual shift option, it is really a bit of electromechanical trickery.
Q: A good friend of mine started having transmission problems with his 2019 Ford F-150. The 10-speed transmission frequently jerks when shifting, which is a known issue. Ford has not issued a recall, and I don't know if they have sent out any technical service bulletins.
The powertrain warranty is still in effect, and the Ford dealership told him that he needs to have it replaced with a rebuilt or remanufactured unit. They said that "there is no such thing as a new transmission."
Are there any specific questions he should ask the dealership about this?
A: In many cases with transmission replacement, what the customer is getting is a remanufactured unit.
Years back, defective transmissions were rebuilt in the shop by the technician who was working on the vehicle. Today, those remanufactured units are rebuilt by specialty shops that are contracted with the vehicle manufacturer.
Since the dealer is stating this is a known problem, I would ask if Ford can extend the warranty on the transmission.
John Paul is the AAA Northeast Car Doctor. He has more than 40 years of experience in the automobile industry and is an ASE-Certified Master Technician. Write to John Paul, The Car Doctor, at 110 Royal Little Drive, Providence, RI 02904. Or email jpaul@aaanortheast.com and put “Car Doctor” in the subject field. Follow him on Twitter @johnfpaul or on Facebook.
This article originally appeared on The Providence Journal: What happens if the electronic emergency brake fails? | Car Doctor
