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I put a new gas cap on my 2014 Subaru Impreza, and the check-engine light went off for quite a while. It’s now on again. What can I do other than replace the cap? – Ronnie

Drivers regularly assume that when their malfunction indicator light (MIL) appears, that they only need a gas cap. The gas cap is only a small part of the evaporative emission control (EVAP) system, which contains and stores evaporated fuel.

While the problem may be located within the EVAP system, we also have to consider that the MIL going off at the same time you replaced the cap was just a coincidence.

The MIL’s only job is to alert the driver that a malfunction exists somewhere within the car’s complete engine-management system.

The powertrain control module (PCM) is constantly testing and retesting all systems, commanding the MIL to illuminate when it has discovered an error somewhere. At times, a sensor will be at the very first stages of failure, resulting in a MIL going on and off.

The gas cap was a good first guess and an easy DIY repair, but it’s clear that something else is going on. Your only path now to rectify the situation is to have the car scanned, diagnosed and repaired.


The brakes were done on my 2005 Toyota Camry last year. Now, if I stop fast, braking hard, there is no squeak. But when I’m going slowly and braking, it’s there. Of course, when the mechanic drove it, there was not a hint of squeak. So I left feeling stupid, and they squeaked again as soon as I left. I’m just really scared when driving with this noise. Any ideas? – Virginia

Squeaks may be generated by a brake part that is vibrating – typically the brake pad. Under hard braking, extreme forces are applied, which effectively lock the pad in place and prevent it from vibrating. However, under light brake-applications, the force may not be sufficient enough to prevent this vibration, resulting in a squeak that is only present under your described conditions.

Don’t be afraid to head back to your mechanic and go for another test drive, with you as the driver. Once they hear the noise, they should be able to rectify it for you.

Additionally, the quality of aftermarket brake parts varies. Inferior brakes can cause a host of material-based noises.

I offer clients the best parts on my initial quote. If cost is an issue, we offer cheaper alternatives while clearly stipulating that brake noises may be out of our control.

Most premium manufacturers will offer noise warranties when pads and rotors are installed together at the same time.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing “Lou’s Garage” in the subject line.

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