Worn brake pads can adversely impact your ability to bring your car to a halt. This can be especially dangerous in an emergency situation when adequately working brakes are a must to help you stop your car promptly. There are some telltale signs of pending brake problems; do you know what they are? Awareness of a problem is the key to avoiding potential harmful consequences; let’s examine some well known warning signs.
Signs of pending brake trouble include the following:
Pulling of the car from one side to the other
Brake pedal pumping
Sudden and hard brake pedal
Spongy brake pedals
Grinding of the brakes
While some of these problems may necessitate you replacing other brake components, an inspection of your brake pads should reveal that they are worn and are in need of immediate replacement.
Your next course of action depends on your expertise, your time, and on your wallet. Most garages offer a free brake inspection and this can be a wonderful opportunity to have someone else inspect your system to confirm your findings.
Ask your mechanic for a complete diagnosis of your brake system and an estimate on what parts and repairs will cost you. A good garage will give you a print out showing a fairly close estimate of what your costs will be. Throw in your local taxes and the price quoted should be within 95% of the final cost, barring an unforeseen additional problem being detected [for example, brake master cylinder failure].
If you feel reasonably confident that you can do the work yourself, you stand to save yourself plenty of money, at least in labor costs. You can save money with parts, too, by shopping around; the highest prices you pay will likely be through your dealer’s parts department. Prices at a national auto parts supply store should be lower, while prices through an online wholesaler should be about the lowest available as they purchase directly from the manufacturer.
If you decide to purchase online, only obtain parts from a reputable dealer selling parts from trusted manufacturers. Be careful of those sites selling generic parts from overseas merchants. Make sure that you can return what you purchase, if needed, to address in based in the U.S.
So your car’s CEL (Check Engine Light) is on and you had the codes scanned at a local parts store. Your car has either a P0171, P0174 lean fault code or both stored in the computer, these codes are based on Oxygen Sensor (O-2) readings. A lean code or codes indicate that there’s too much oxygen in the exhaust. Remember parts stores have employees that have good intentions but they may not have the experience necessary to interpret what the trouble codes really mean. These codes are based on oxygen measurements in the exhaust. A common mistake with lean codes is to replace the oxygen sensors. This could be a very expensive mistake that will not fix the problem. Especially if both codes are present, because the chance of both O-2 sensors failing at the same time is very unlikely.
Most likely the cause is a vacuum leak. A vacuum leak can be caused from a vacuum hose, intake gasket or maybe even a leak in the air intake hose from the MAF (Mass Air Flow Sensor). Listen for a hissing sound that may lead you to the source of the problem. Some technicians will use a propane bottle with a hose attachment to help pinpoint vacuum leaks. With today’s computers it’s not quite as easy to check for vacuum leaks this way because the ECU (Electronic Control Unit) will compensate quickly for the added fuel and a change in idle is harder to notice. Oxygen sensor readings can be monitored with a scan tool while checking for leaks with propane, by looking for increased readings when enriching the mixture. Another way technicians can check for vacuum leaks is with a smoke test. By introducing smoke into a vacuum hose on the engine, the leak will be revealed when the smoke escapes from the problem area.
Aftermarket air filters that use oil on the element can sometimes damage the MAF. Over oiling the air filter may allow some excess to get on the MAF sensor wire or element. This can alter the reading, fooling the ECU into seeing more or less air flow therefore changing the air/fuel mixture incorrectly. I once worked on a car that would not start that had a problem with a MAF. When looking at the wire in the MAF, there was a burned piece of trash that made it’s way past the air filter. After cleaning the sensor the car ran perfectly. The ash that was on the MAF sensor wire was altering the reading by enriching the mixture so much that the car could not run. After talking with the customer, he said the air filter was just changed. This was obviously when some trash got into the air intake hose that settled on the hot wire of the MAF.
Fuel Pressure could also cause a lean condition. If the fuel filter is clogged or the fuel pump pressure is low, there could be higher level of oxygen in the exhaust also. Most of the time though, the ECU will compensate for the reduced fuel volume. So this is one of the least likely causes of a lean code.