Check Engine Light

Question..... I was wondering if anyone could help with a problem my wife has been having with her 2003 Jeep Liberty Limited. The vehicle has 88K miles and runs well. About 2 months ago, the check engine light came on and wouldn't go off. My wife took it in for an early oil change and diagnostic. The oil change didn't solve the problem and the diagnostic showed nothing wrong. Then a few days later, the light went off. A few days later the light came back on again. She then brought the vehicle to a mechanic and, after diagnosing the vehicle for over 2 hours, decided that the gas cap needed to be replaced. The light went off. 2 days later, the light came back on again. Brought the vehicle back to the same mechanic who did a full oil change, tune-up and replaced the gas sensor. The light went off. That was yesterday. Today, the light came back on again. I refuse to bring it to another mechanic and have them "guess" at the problem, charge us an arm and a leg and wind up having the liht come back on a few days later. Any suggestions?

You can contact me at adamscrnr@comcast.net

Thanks to anyone who can assist..

Jim

It has to ba done with a scanner. Take it to a autozone or other parts store and they will read the codes

Don't waste your time at autozone. Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. 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. BCLEAR.

BCLEAR - your answer in reference to the engine light coming on due to an emisions problem may be on target. My wife went to put gas in our 2002 Jeep Liberty and noticed that the gas cap was missing. She was concerned that an old friend that she is fuding with put sugar in the gas tank and stole the gas cap in the process. Shortly after fueling up the check engine light came on. Obviously I did some research on what sugar in the gas does and learned that most of the stories are urban legends because sugar does not disolve in gas. The engine light came on only after she drove the car without a gas cap. I will get a new one today and see if that clears out the code. Don

Best thing to do is remove the negative cable on the battery and let set over 15 to 20 min. Then reconnect and see if it went out some times its just a matter of resetting the computer for routine maintenance. Had light come on after fuel injection cleaning. Pulled negative terminal and the light has never come back on.

_ Comment: I find that everytime I fill my almost emtpy gas tank with gasoline containing 10% ethenol my check engine like comes on. Only after filling my almost empty gas tank again with gas not containing ethenol my check engine light goes out. (after half a tank of gas is burned.) You can read the content of the gasoline that you are purchasing usually on the pump. Most time it is in small lettering. I hope this is helpful it works for me. Try this first you won't waste alot of trips to the dealer and most dealers don't know this. I just descovered the pattern myself.

At about 90,000 miles, my check engine light came on as well. My mechanic ran diagnosis on it....I had cracks in my emissions tubing. After replacing the tubing...cheap fix...the light went off.

With the engine off, press and hold the odometer reset pushbutton. Start the car. Keep finger on odometer reset pushbutton until "oil life" message starts flashing. Release the button.

Maybe. You need to get an ODBII diagnosis first to see what is causing the light to come on. ed724 It is worth doing since it is a maintenance type of need. There are tune up parts that could cause a check engine light. If not then read below: Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. 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. The " check engine light" is by far one of the most misunderstood technological advances by the public. I am sure I will revise this as time goes on, as it is an in-depth understanding for the public. It is a warning light that is illuminated when there is a problem with 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

If these two lights come on together then the extra traction sensor is broken and needs to be replaced when the sensor is fixed the check engine light will go off and the ets light will work properly again.

Turn the ignition to the "ON" position. Not the "RUN" position. The engine should be off. With the ignition in the "ON" position fully press the gas pedal down 3 times within 5 seconds. The light should flash twice. If it doesn't you need to try resetting the system again. read your owner"s manual

well there is two ways one you can do is take your battery cables off and leave them for 5mins other option is to go to autozone and they will reset your codes for free

On the dash a yellow light that is in the shape of an engine on the lower left side of the information center.

Have vehicle scanned to determine the problem

Wave properties. these allow it to be reflected, or partially reflected by various surfaces.

Fuel pump relay

or

Knock sensor if stall after maybe 2 miles

YES IT CAN SO GET IT FIXED

there could literally be thousands of causes...most auto repair places will read the code and tell you what is wrong for free...

Funny, you could have had a trained dealership technician, like me, tell you what the problem is for less than you spent on that EGR valve. Penny wise and dollar foolish my friend.

Or simply do some more trouble shooting. Many times the engine code doesn't tell the whole truth on any vehicle. Could be a DPFE sensor or a vac regulator. More that likely the DPFE sensor easy fix. Good Luck

See "Related Questions" below for more

Misfire can be caused by many different types of problems with your valves. It could be burned or leaking valves, carbon build up on the valves, weak or broken valve springs, worn valve guides or lifters, broken worn or bent rocker arms or pushrods, worn camshafts, improper valve timing, or worn pistons or rings. A misfire is basically when the cylinder is not producing enough air-fuel mixture properly, so your valves may not be supplying the proper amount of air into the cylinder, for the compression to be strong enough for combustion. Faulty: plug, plug wire, ignition coil, ignition module, fuel injector are the most common. Coolant leaking into a cylinder is another. Internal engine problems such as burnt valve, broken valve spring, bent push rod, worn rings.....

In a Manual, your car can stall at red lights because the engine is not receiving gas, this is why the klutch is important.

In Hybrids the engine intentionally shuts off to preserve gas. Then an electric motor starts the car moving when you accelerate again, filling the time gap between when you press the accelerator and the gas engine kicks in.

Pull the 4x4 lever or turn the 4x4 nob depends on what year the truck is

If I'm not mistaken, the code you are refering to is for the Secondary Air Injection system. The system injects air into the exhaust if the car during the first few moments after you start the car. It's purpose is to assist in warming the catlyitic convertors to operating temperature. As this module is part of the emmissions system, you may be covered under Ford's emmissions warrantry. You will need to check with your local Ford service center to determine if your car still applies to this "Emissions Warranty." If you have any more questions feel free to ask.

I have been told that one of the two vacuum solonoids located on top of the EGR and regulator valve assembly are in line with the air pump. I haven't found out which one yet (I need to replace it and am doing on-line research to determine which one it is). If one of these solonoids is malfunctioning electrically, it could also cause the same problem. I paid $400 for a new air pump to be installed and still have the P1413 but the ford diagnostics say "change out the pump". So apparently something is awry here. The mechanic who changed the pump got advice from one of the mechanics at a different shop who is more of an expert, and I'm relaying what I was told here. I hope it helps both of us. I'm going to go to Ford and determine which solonoid it is and replace it myself. They are both "on top" of the pipe where the EGR 'master regulator' is, and have both vacuum hoses and electrical connections to them. One of these two is likely to be the cause.

there is also an electronic relay mounted to the side of the air pump. I had this problem, changed the relay out. However I still got 1 spurious P1413 after I verified the electric air pump would spin. So maybe there are multiple causes here. I took the precaution of using electrical contact cleaner on the wiring before I re-connected it also, just in case. But if there is a problem between the relay and the computer, I bet this would cause it as well.

First, if it is something like a loose gas cap, just tighten it and it will reset itself in the next 100 miles or so. If it is something else, like a leaky gas cap it will never reset. But to reset the OnBoardDiagnostic (OBD)Computer... Go to eBay and search "obdII" and buy one, they run about $50.00 including shipping. There are two types, ISO for Chrysler and some Japanese, and the other one for all the others like Ford and GM. There are several that are both, that is the kind you want. Be sure to email the eBay seller and ask if it is used with your year and model. (1996 was a changeover year for OBDII technology, so this advice may not apply to everybody--but the dealer service guy can tell you over the phone--ask him if it is OBDII compliant.) When you get it, you just plug it in and let it cycle 4 or 5 times and it resets everything. You then have to drive your car for 50 to 100 miles for the onboard computer to test everything, and in the meantime your car will fail smog checks because it has no history in the computer and the smog test procedure demands a history even if there is no pollution. Cut and Paste http://search.ebay.com/OBDII for a list of them for sale on eBay. Most units come with a list of generic fault codes so you can tell what the problem is, this could be very helpful.

Borrow or buy an engine code scanner to find out what code is stored. The fact that the "check engine light" is on is a huge clue. That may give you all of the information that you need to figure out what's wrong.

Use an automotive computer code-scanner to read the stored code. Then you'll know why the "check engine" light is on.

Have vehicle scanned at auto parts store--most will do this free

it has to be reset if you disconnect the battery for a few minutes should do it

The code is spelled out in the MB Diagnostic manual or the 91 MB intro book

An engine cylinder misfire has been detected if your check engine light is flashing on and off

If the check engine light is blinking that means an engine cylinder misfire has been

detected