Payless 4 Wheel Drive

Your vehicle's regular brakes should work fine, but the antilock feature that prevents wheels from locking up during braking will not work. In addition, if your vehicle has stability control and traction control, those will be disabled as well because those systems rely on the same wheel-speed sensors as the antilock system.

All 2012 and newer vehicles are required to have stability control, so they also have ABS and traction control. Many older vehicles also have some or all of those features.

The ABS warning light (usually yellow, amber or orange) should come on briefly every time you start your engine as part of a system check. If it stays on, that means something isn't working and the system has been shut down.

With ABS, sensors mounted at each wheel monitor the speed at which the wheels are turning. If one is turning slower than the others during braking, that indicates it is locking up, which could cause skidding and loss of steering control. ABS is supposed to intervene by rapidly "pumping" the brakes at the wheel that is locking up, allowing it to spin so that the driver retains braking and steering control.

Here's what causes this:

A blown fuse for the system

A wheel-speed sensor that is damaged or covered by road grime

A broken wire between the sensors and the ABS controller

An ABS controller that has stopped working

A pump and valve that apply the right amount of brake fluid pressure to each wheel to prevent locking can also trigger an ABS warning light when those items go bad.

If the red warning light for the regular brakes comes on, that typically means your vehicle is losing brake fluid or the brakes are so worn that you don't have normal stopping power. Either of those situations warrants immediate attention.

If your vehicle's engine misfires, hesitates, stalls, gets poor mileage, is hard to start or has failed an emissions test, it clearly needs something, though a tune-up in the traditional sense might not be the cure.

If you tell a repair shop your vehicle needs a tune-up, the mechanic should ask what you feel the signs are that you need maintenance before recommending any service. Just like a doctor should ask what symptoms you're experiencing, a mechanic should seek to diagnose the problem. And just as a doctor may recommend some tests, a mechanic may do the same.

You can speed the tune-up process by being ready to describe what happens and when (such as whether your car hesitates when the engine is cold or when passing at highway speeds), any sounds you hear and what you feel when your car’s “illness” shows up.

One caution about lower fuel economy: You should expect it to go down at least a little during the cold months, and maybe a lot. Colder temperatures make your engine and charging system work harder. In addition, winter gasoline blends have slightly less energy content than summer blends, so they don’t deliver as many miles per gallon. A tune-up won’t make Old Man Winter, or his effects, go away.

What are the signs and symptoms that might make you think your vehicle needs a tune-up?

A misfiring engine (when spark plugs ignite at the wrong time) could be caused by worn or fouled spark plugs. Bad spark plugs can also cause low fuel economy, hard starting and sluggish acceleration. Most plugs, though, should last 100,000 miles or more, and engine computers do a remarkable job of compensating for worn plugs, so that might not be the main or only culprit.

A dirty or clogged engine air filter is more likely to reduce acceleration than fuel economy, according to tests conducted by the EPA. Because filters get dirty gradually over time, you might not notice a small but steady loss of performance until your car is accelerating like a turtle. But if you haven’t changed the filter in a couple of years (or sooner in areas that have a lot of soot in the air), that could be part of the problem.

Engine deposits caused by low-quality or contaminated gasoline create drivability problems, and the cure for that might be a fuel system cleaning, either by a repair shop or with a gas-tank additive.

An illuminated check engine light signals when something is amiss in the emissions control system, but depending on what the issue is it could also affect fuel economy or engine performance, so don’t ignore it. A faulty oxygen sensor, for example, leaves the engine computer in the dark about how to set the air-fuel mixture, and that can result in poor fuel economy.

An old oxygen sensor (say, 90,000 miles or more) may still work well enough that it doesn’t trigger the check engine light but could still hurt fuel economy. Engine performance can also be reduced by more serious internal problems, such as valves that don’t seat properly or worn piston rings, or by restrictions in the exhaust system.

Because the same symptoms can suggest different problems, and there are often several possible causes and cures, it’s better to consult a professional mechanic than to try to be one if you have neither the experience nor the right equipment to diagnose drivability problems. In short, rather than ask for a tune-up, tell a mechanic what you’re experiencing and ask him or her to find the cause.

Lights

You need lights to see and be seen, especially when rain, snow and fog reduce visibility. Check that all lights are functional, including marker lights, turn signals, hazard lights, brake lights, reverse lights, taillights, headlights and fog lights. If not equipped, perhaps now is a good time to think about installing aftermarket fog lights.

Wipers

A good guideline is to replace wiper blades every six months, but they may wear sooner. Now is a good time to replace any wiper blades that streak, chatter or don’t clear the windshield properly. Don’t forget to stock up on winter washer fluid, too.

Tires

Don’t worry about snow tires yet, but check that your summer or all-season tires have at least 4/32 inches of tread depth remaining. Look for abnormal tread wear, which may indicate an alignment or suspension problem. Cooler weather causes tire pressure to drop, so inflate tires to the psi indicated by either the owner’s manual or the tire and loading label on the driver’s door jamb.

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