Q: When should I check different systems for needed maintenance?

If the engine revs up fine, the problem is in your drivetrain (transmission) Check your transmission fluid and add as necessary and see if that helps. If it is extremely low, a leak may be present. Identify and repair leaks...

If the fuse is good, the only other things it could be is the button (in the steering wheel) or the horn itself. I saw an issue like this before on the same vehicle you have, the wire to the...

I think it is possible that you may have shut an object of some kind in between the trunk latch and the trunk lid when you shut the trunk. If an object becomes lodged in the correct spot, this can...

This is a problem that may not be able to be fixed. The noise is from the brake pad material metal (https://www.yourmechanic.com/article/why-do-brakes-squeal) in the pads squeaking on the rotors when you go in the opposite direction of the pad's normal...

The only way to gain insight as to what happened it to retrieve the diagnostic trouble codes associated with the Check Engine Light. Even if the Check Engine Light is not on anymore, you may be able to retrieve history...

These bells indicate a problem that the built-in diagnostic system is unable to indicate on the dash (usually a burned out fault indication bulb). Replace the burned out indicator bulb on the dash, then check out the original problem by...

Hello. You don't specify the mileage on your Focus, but the symptoms suggest low internal hydraulic pressure in the transmission (despite the recent fluid and filter change), or a weak forward clutch pack. If you would like to have this...

Hello. Thank you for writing in. It would be beneficial to have the diagnostic codes (https://www.yourmechanic.com/services/check-engine-light-is-on-inspection) that were pulled from the scan. Have you checked the level of the coolant? You should start there. Make sure that the thermostat is...

The fluids are incompatible and brake fluid could damage the pump and rack. If you haven't driven the car yet, or even turned it on, drain the reservoir by removing one of the lines from the bottom. Thoroughly and repeatedly...