Either be patient with the mechanic and try hard to understand what he is telling you. Many of my customers jump to the conclusion "that nothing shows up" after explaining what is happening in that particular situation.
There are "monitors" or self tests the computer runs the car through a drive cycle, if a problem occurs, it may not run all of the self tests until that problem is taken care. Therefore, another problem may exist. It is emission related. OR hook up a scanner that is capable of clearing codes, and hope that none are still active. Disconnecting the battery can create other headaches and will not likely solve your dilemma. Best bet is to contact the local snap-on dealer and have him refer you to a known good shop that specializes in this technology-he will know.
The " check engine light" is by far one of the most misunderstood technological advances by the public. This is an needed in-depth understanding for the public. It is a warning light that is illuminated when there is a problem affecting the EMISSION SYSTEM only. Emission system being the pollution control system. Don't get a hard on against it as it is a good thing once you understand it. One point that was brought up a a recent meeting of technicians was that the amount of hydrocarbons is greater when the gas cap is left off than when the engine is running. Hydrocarbons are part of pollution emitted as gasoline evaporates. Going a step farther, one facet of the emission system is the "Evaporative" portion. This is when the fumes from the gasoline are leaking from the system into the outside air. This is one part of the emission system that can trigger a check engine light. I would say that about 7% of the vehicles that have a check engine light are the result of a loose or inadequate gas cap. But understand that many scenarios are possible with the "check engine light" The vehicle's powertrain computer (note that some vehicles have 17 different computers) will run a series of self-tests. They will only run under certain criteria. And they can be vastly different from manufacturer to manufacturer. Some self-tests are not run until preceding ones have run successfully. So if there is a problem in one particular area that is preventing another self test from running, you can have a situation where one problem is fixed, but another still exists. If you fix a problem and drive the car through a drive cycle that sets the monitor (or self test) the light will go off as it passes that criteria that triggered it in the first place. After 1996, the auto industry went to a idea called OBD II (on board diagnostics). This was to get all the manufacturers onto a similar plane for troubleshooting and powertrain control. While they still differ vastly, many corrections and adaptations were made for technicians to better fix the check engine light problems. Prior to this there were so many different and poor troubleshooting data from a check engine light problem that resolving the problem was much more difficult. Many early warning light of this nature were set to illuminate based on mileage. An Oxygen sensor was one of the things that were meant to be replaced when that mileage was hit. This is much like many current "Change oil lights� that are set based on a pre-set mileage.
Yes, a loose gas cap will cause the MIL light to go on, but tighening it will turn it off after a few restarts. Mechanics, even SAE certified mechanics generally do not know how to diagnose a MIL problem. Normally, each MIL code has a diagnostic procedure, e.g. flow charts with diagnostic steps. Dealers have this information but, for obvious reasons, do not share it with the public or with non-dealer repair shops. Nevertheless, the latter type repair shops should not guess at the problem, but should obtain this information rather than use "stab in the dark" techniques. Example: I had a MIL code that indicated High Voltage on a Particular O2 sensor. Sometimes the O2 sensor is the problem, but not always. After (stupidly) replacing the Oxegen sensor multiple times and not solving the problem, the mechanics assumed the problem had to be the computer or something else. after doing research, I learned the a higfh voltage on an O2 sensor means the fuel mixture is too rich. After checking the vacuum ports and air intake and air filter, I discovered a defective air Temp sensor and replaced it, solving the problem. I am really upset with the mechanics for not finding this, and for guessing (not knowing) what the problem really is. Don't believe anything the mechanics tell you, because remember, it's not their money, it;s yours.
I was told by a mechanic that whenever the engine light is on, it's because of an emission problem. To find out what kind of problem, you need to have it checked by a diagnostic machine at an auto shop.
take it to your mechanic so he can run a diagnostic.
Take to a qualified mechanic for a diagnostic
take it to a dealer or a qualified mechanic for a diagnostic
Take it to qualified mechanic for a diagnostic
If the check engine light is on for your 1991 Toyota Cressida, that makes that some repairs need to be made to the engine. Taking the car to a certified mechanic to perform a diagnostic test can confirm if there is any issues with the engine.
You must scan the computer to find out the code first Go to a qualified mechanic for a diagnostic
It is on because the computer has detected a problem with the emissions system. Take it to a trusted mechanic for a scan and diagnostic of the problem.
It means there's something wrong. You need a mechanic to run a diagnostic in order to determine the cause.
To answer that, you need to get a mechanic with the correct programme on his laptop, to plug into the diagnostic socket and interrogate the engine control unit. The fault code displayed will tell him what's wrong with the car.
The best way to reset the engine warning light on a Nissan Primera p12 would be to take it to a mechanic. It is best to have a mechanic check it out to make sure nothing is wrong that could malfunction and put someone in danger. The mechanic will be able to reset the engine warning light.
A service engine soon light on a Nissan Pathfinder can mean many things. There could be a bad spark plug or even an engine malfunction. A mechanic can run a diagnostic check to see what the problem is.
A knocking sound while your car is moving is probably coming from the engine. A certified mechanic will be able to perform diagnostic testing.
The computer finds wrong data from one of the sensers Go to a qualified mechanic for a diagnostic
On a 1994 Ford Ranger ( which is OBD I , EEC IV ) should have an EEC TEST connection in the engine compartment ( P.S. I'm not a mechanic / technician )
If the engine is fuctioning properly try disconnecting the ground battery terminal for 1 minute. If the engine is fuctioning properly and this does not cure your needs. It will have to be reset by a mechanic with a diagnostic machine for Toyota.
There are two diagnostic connection ports, there is a diagnostic connection port below the dashboard on the drivers side. A second diagnostic port can be found in the engine compartment on the firewall.
The mechanic did my car's engine for free.
In one weekend by a backyard mechanic or small shop ... NO.With a lot of time/money and chopping the engine bay down to nothing ... YES.
have towed to a mechanic for a diagnostic
The skills and/or schooling need to become a mechanic are knowledge on engine management, variety of systems involved in mechanical work, diagnostic abilities, management skills, and customer care.
It would probably have to be hooked up to a diagnostic machine. Or you might be able to get a code reader to see if that does it.. but I doubt it if its a 2004, it probably will more than likey require the expensive diagnostic machine that is at mechanic shops.
Research has shown that most airplanes have an engine management system in place that provides diagnostic assistance for an airplane mechanic. Some of the things that need to be monitored are cylinder inspection, oil monitoring and fuel system setup.
I work in the auto parts business and you need to take it to a mechanic so he can run a diagnostic check and tell you exactly what is making the light come on.
The check engine light is there to tell you when the computer has stored a diagnostic code. Use a code scanner to read the code and find out what's wrong. We have a 94 and 96 Ford Aspire. The check engine light stays on most of the time. At inspection time, we take it to our mechanic and they use a computer to turn the light off. It seems to be a defect in many Ford Aspires, as our mechanic says nothing is wrong with either car. We are constantly driving them.