Check Engine light came on while driving.

[SierraK1500]

A few days ago the check engine light came on in my 2005 Impala. First thing I checked was the gas cap to see if it was loose or ill fitting. Seems the heat dried out the rubber gasket as it was hard. The cap moved around even when clicked a few times. Bought a new Stant gas cap for the car. Fits tight.
Just tanked it up a few minutes ago. The car runs fine. No change from before.

If the light does not go out soon from sealing the system, where can I take it to have the codes read? Any good national parts house read it for free?

Car has 160988 miles.

Thanks for your help.
John

[matthew24u]

autozone can`t believe i said that i hate autozone but advance auto parts or pep boys also does it. I would see what triggered the light before doing anything else. let us know what ya find!! always stuck in diagnostics

[SierraK1500]

Thank you for your prompt response Matthew!

I will find out the codes and see if it fuel related. Figured its minor since the car itself runs like a bear. Will let you know my friend!

John

[rkvons]

Going to a parts place and waiting in line just to get a chance to have some kid go out to your car, ask for your keys and fumble around under your dash looking for the OBD port makes getting one of these:

http://www.amazon.com/Autels-MaxiSca...maxiscan+ms310

a no-brainer. I have one of these, and it is definitely one of the best things I've ever purchased. You can drive around with it hooked up and check your I/M readiness, which is what I'm doing now, because I need to get my car tested soon. You can't do that at Autozone. Many benefits to having one of these. You want to buy a used car from a stranger. the check engine light is off. Did he just turn it off? You can find out. The list goes on and on.

[mco65]

Originally Posted by rkvons

Going to a parts place and waiting in line just to get a chance to have some kid go out to your car, ask for your keys and fumble around under your dash looking for the OBD port makes getting one of these:

http://www.amazon.com/Autels-MaxiSca...maxiscan+ms310

a no-brainer. I have one of these, and it is definitely one of the best things I've ever purchased. You can drive around with it hooked up and check your I/M readiness, which is what I'm doing now, because I need to get my car tested soon. You can't do that at Autozone. Many benefits to having one of these. You want to buy a used car from a stranger. the check engine light is off. Did he just turn it off? You can find out. The list goes on and on.

Agreed! A code reader is definitely worth the cost and are available at most parts stores including Wal-Mart (I think).

[oldblu65]

Originally Posted by SierraK1500

A few days ago the check engine light came on in my 2005 Impala. First thing I checked was the gas cap to see if it was loose or ill fitting. Seems the heat dried out the rubber gasket as it was hard. The cap moved around even when clicked a few times. Bought a new Stant gas cap for the car. Fits tight.
Just tanked it up a few minutes ago. The car runs fine. No change from before.

If the light does not go out soon from sealing the system, where can I take it to have the codes read? Any good national parts house read it for free?

Car has 160988 miles.

Thanks for your help.
John

Even if the gas cap was the culprit , replacing it will not automatically turn the CEL off . It will turn itself off after some preset amount of drive cycles * ( * that is starting the car , driving it enough miles to get it to normal operating temperatures , then shutting it off and letting it cool down completely ) . This is considered a drive cycle and it takes a predetermined amount of these cycles for the CEL to be turned off by the car's computer . Of course , the easiest way is to have someone with a scanner to turn it off ! You really need to have your car scanned to make sure the CEL isn't indicating a different problem rather than just the cap . Just my $0.02 !

[SierraK1500]

Had the codes read.

P0135

Oxygen sensor is bad. The kind manager at O'reilly's allowwed me to reset the codes and clear them only to confirm the light turning back on.

The sensor is 53.00 at O'Reilly's where is the sensor on which manifold?

Hopefully I can change it myself without going under the car.

John

Thank you to all the responders,

[danielsatur]

It could be as simple as a fuse to H20 sensor, or a bad connection.
H20 sensors can be rolled from bank 1 to bank 2 for troubleshooting.

[oldblu65]

Originally Posted by SierraK1500

Had the codes read.

P0135

Oxygen sensor is bad. The kind manager at O'reilly's allowwed me to reset the codes and clear them only to confirm the light turning back on.

The sensor is 53.00 at O'Reilly's where is the sensor on which manifold?

Hopefully I can change it myself without going under the car.

John

Thank you to all the responders,

Since your Impala is a V6 , I suspect it will have an O2 sensor on both manifolds ? Did the code specify bank 1 or bank 2 ? Generally speaking , there is normally one downstream ( beyond ) the catalytic convertor as well .

[Tech II]

Chances are, the vehicle has two O2 sensors....one before the cat, and one after the cat......

The one in question, is the one before the cat(if there are two before the cat, it will be on the side cylinder #1 is on) .....but this code is for the heater circuit...could be fuse problem, shorted/open wire harness, or the sensor itself.....check the heater circuit, before replacing the sensor....

[SierraK1500]

finally had the sensor replaced and I did purchase a code reader at Advanced for 50 bucks. The sensor was replaced and the light was still on. I was told the mechanic was not allowed to reset the light. I did it myself today and so far I have driven the car and the light is out. told me it would take 80 miles for the computer to reset the light. How true is that?

[Tech II]

Would like to know why he wasn't allowed to clear the code for you......takes less than a minute.....

A drive cycle is not based on mileage...it's based on driving the vehicle under the criteria for the drive cycle....have seen people drive their vehicles over 200 miles, and not reset "ALL" the flags, because all the criteria were not met....

Every time you clear a code, all the flags are reset to not run/not passed...then as you drive during a drive cycle, as each criteria is met, then the test for each monitor/flag is run and passed....if it doesn't pass, then a code is set....

For those out there thinking of buying a code reader, let me suggest going one step up to a low end scanner.....code readers, depending on brand/capabilities go anywhere from 20-50 bucks.....they read codes....they clear codes...some check monitor readiness.....some even give description of codes.....

The step up to a scanner gives you that plus, the ability to see PCM live data.....the ability to graph this data.....view freeze frame data.....perform limited tests......check modules....and the best part is, it does this for different lines of vehicles....over the years, the price for performing all these functions have dropped dramatically......you can now get a scan tool to do all these functions for 50-60 bucks.....

The price goes way up, when you want to get a little more sophisticated.....like a larger screen, to see more data at the same time.....the ability for two way communication, whereby you can command the PCM to perform certain functions for testing......making it wireless....and so on........

So for 20-30 bucks more, I'd get a scan tool rather than a codes reader....