"check engine" light....whats the deal??

[chin311]

SO, my "check engine" light came on yesterday in my 96 Corolla (1.6L) hah, anyways, it has about 97,000 miles, in good mechnical shape, just had some preventative stuff done (coolant, trans fluid, etc), only thing i havent done since ive owned it is a tune up (ie, spark plugs, wires, etc), and this light came on yesterday while i was driving, even tho everything is running identical to the way it has been for the last 6 months since i've had it....can i still drive with the light? should i take it in right away? am i ok for a while??

what do ya think? help...

thx

 

[ScoobMaster]

Go to your nearest Autozone.

The will plug in an OBDII diagnostic reader and tell you what code is being generated and what it means (for free!)

It may be an easy to change sensor (oxygen, coolant switch, EGR valve, etc) has failed. This way if that is the case you can just buy the part and change it yourself. Don't go to a dealership unless the code indicates a problem you don't feel comfortable handling yourself - the dealer will charge $30-50 JUSt FOR READING THE CODE!!!!

 

[Zenmervolt]

Probably nine times out of ten that light means an emissions control problem. At your mileage I would not be surprised if it were a failed oxygen sensor, but the best thing to do has already been suggested. Take the car somewhere and have the codes read.

ZV

 

[alm99]

Its going to blow up...get out now!

 

[chin311]

Originally posted by: ScoobMaster
Go to your nearest Autozone.

The will plug in an OBDII diagnostic reader and tell you what code is being generated and what it means (for free!)

SeriouslY? toyota wanted $30 bucks just to throw it on the computer. Oxygen sensor, i havent messed w/ the one on this car..

 

[ScoobMaster]

Yes, I am serious. Just go to the counter at any Autozone and tell an employee that the check engine light is on and you would appreciate it if they could plug in a code reader. This will cost you NOTHING as opposed to paying a dealer $30+ for 30 seconds of "work"

 

[Purgatory-Z]

FYI - Autozone may not help you. I went in with my Subaru WRX to have a CEL checked (just to verify, I knew it was emmissions control because I have removed all but 1 cat for a much more free flowing exhaust) and they told me that they don't do imports...

For Subaru, a solid CEL is emmissions related, a flashing CEL (much much worse) is a knock/timing problem and should be immediately checked out. Toyota may have a similar system, it might be worth checking out.


-Purg-Z

 

ScoobMaster

No offense meant but I wouldn't bring my bicycle down to Autozone to have them look at it, who wants a person who has no Automotive tech experiance diagnosing your vehicle ?

Have the dealer pull the codes to find out what sensor went bad, then (If it's easy for you), replace the sensor yourself.

 

[Spamela]

this has happened a couple of times with my ranger.

all you have to do is disconnect the battery for 20 minutes, then re-connect.
if the check engine light is still on, then go see the dealer.

it can come on for all sorts of non-serious reasons, like starting/running the car
with the gas cap not fully tight.

 

Keep in mind though, the opposite may also be true. My check engine light came on for my Ford Explorer...had the code read, and it came back as a "0401 - Insufficient Flow : EGR Valve".

Simple I thought, replaced the EGR valve...had the computer reset and BAM, the Check Engine light comes back on 15 minutes later....same damn code. Turns out the EGR valve was never the problem (wasted 70 bucks), and I needed 2 sensors replaced to the tune of 250 bucks. I had been driving aroung on the Check Engine light for close to 2 years with no problems, but the Emmisions tests for 96 and newer cars auto-fail now if the CE light is on, so I was forced to actually fix the issue.

Had I gone to the dealership, I would have saved the money it cost me to purchase that EGR valve...so its a double edged sword here.

Good Luck either way.

The tech who pulled the codes did it wrong, Ford has three distinct ways to pull codes, KOEF (Key On, Engine Off), KOEO (Key On, Engine ON) and Key On, actuate sensors (Depress gas pedal, shift gears, hit brakes etc.)

If this procedure is not followed, all the codes stored in the ECM will not be displayed.

 

[amnesiac]

CHECK YOUR GAS CAP

9 times out of 10, the cap to your gas tank isn't on tight enough which screws up the readings and turns on the Check Engine light. If it was indeed loose, tighten it and wait about 24-48 hours for it to fix itself.

 

BAH, I took it to 2 different places before buying the valve...They showed me the code, as a matter of fact it was the same code pulled by Ford...but a different part of stated system needed to be replaced. Had I taken it to Ford first, they would have seen the code, diagnosed what actually needed to be replaced and saved me 70 bucks

Exactly, if the codes were pulled by an experienced tech who knew how to properly pull the codes, the fault would have been diagnosed correctly because all the codes would have been retrieved, this information is critical to properly diagnosing the problem.

 

[chin311]

Just got back from Autozone. Code came up as "EGR FLOW INSUFFICENT", the new valve is $132.99. there are some other little EGR things like "position sensors" etc etc. Should I take it to the dealer or monkey with it myself? If anyone knows about WHERE the valve is, how to fix it, etc etc, please help.

Car is: 1996 toyota corolla, 1.6L automatic.

 

The valve is most likely not defective, just carboned up, unfortunately I cannot guide you through the repair on a BBS, it is just not practical to do so.

Here is a rundown ;

To locate the EGR valve, look at the exhaust manifold on the front of the engine, see the heatshield ?, good, look carefully for a discolored steel pipe leading away from either the right or left side, this pipe feeds the EGR valve, follow the pipe until you come to theE.G.R. valve, carefully remove the pipe connections, vacuum lines and electrical connections, remove the E.G.R. valve, turn over, you will see a pintle (A small finger like metal needle), this moves up and down and controls the amount of exhaust gas recirculation, carefully clean the pintle and the passages of carbon with carburetor cleaner, reinstall in the reverse of removal.

Once this is done, disconnect the negative battery terminal with the ignition key removed from the ignition, reconnect the battery after ten minutes, start vehicle, check for leaks and watch to see if the check engine light comes back on.

Edit;

Be very careful when removing the electrical connectors, these are weather proofed sealed connectors, carefully depress the locking tab and remove, under no circumstance should you have to force them off.

 

[chin311]

thnx roger, very informative.

I'll check all that out, i know i shouldnt have to fully REPLACE the valve since i can clean it out, also autozone had some other little parts like "EGR position sensor", etc etc, i shouldnt have to worry about those? just cleaning the valve??

 

[AmdInside]

I think its ironic that the "check engine" light is hardly ever really caused by the engine.

 

I'll check all that out, i know i shouldnt have to fully REPLACE the valve since i can clean it out, also autozone had some other little parts like "EGR position sensor", etc etc, i shouldnt have to worry about those? just cleaning the valve??

Most of the time it is just a carbon problem, as the valve builds up carbon, the valve has to open farther for the same amount of exhaust gas recirculation, the position sensor senses this, eventually the valve cannot open any farther (At it's limit of travel), this trips the trouble code.