Nairalanders, plz i need advices and suggections.
My 2001 toyota Corolla lately displayed the Malfunction Indicator Lamp (Engine Check Light) while i was driving and since then it has remained on when ever the car is 'ON'
Note: the Car was last serviced 2 weeks back at the regular AP Lube outlet.

What could be the possible cause/causes of this indication ?

Check Engine Light is a light that gets itself triggered whenever the ECU discovers an error in any of the car systems. The information is relayed to the instrumental cluster by a Transducer that converts the Mechanical/Electrical Fault to your view on the dashboard.
Dont Panic, even if you service the car one thousand and one times, thats not the solution. The simple solution is getting the Car System Diagnosed. From the result of the diagnose, you will be able to see whatever the problem is. Then, a repair will be suggested if need be.

Call 080 3549 6482. we will help with the diagnose and give you all the technical support.

There is another quick way of resetting the light (non professional), but BEWARE, its sending your car to an early grave if this method is used.

Thanx EASTSIDE ENGINEERING LIMITED for your respond.
I intend to send the car for a scan, but what other likily solution could be to resolve this,
even if its unprofessional as you highlighted.

@Emytech
Check Engine Light can be triggered by a bunch of things; your best bet right now is to have it scanned OR you buy a scan tool yourself and get the codes/fault codes, THEN we can discuss the fault codes here.

It gets easier when you do it on time.

The check Engine light came up on my dash screen(99 Camry) some weeks ago but suddenly disappeared after a week or so without any intervention.

toba1909:

The check Engine light came up on my dash screen(99 Camry) some weeks ago but suddenly disappeared after a week or so without any intervention.

@Toba1909
Beleive me, there must have been something you did; you only did not know. Let me share a very shocking experience I had with my car last week; I had this check engine light on and my scan tool kept telling me "emission" - P0171, P0173, P0141, P0156 - They were all related to emission and the O2 sensor thing, at this I did some search on an owners' forum online I joined as soon as I got the car. It turns out that most of them had changed the O2 sensor (expensive plus repairs too) BUT the thing still kept on showing - someone then pointed out that IF the fuel cap is not properly tightened OR has dirt which could give room for some amount of air, it would trigger the Check Engine light.

What I did was to remove the fuel cap (the fuel tank cover), washed it with petrol, used a flat screw driver to scraped off the dirts that had accumulated on its edge, then I also washed and scraped the part of the fuel tank inlet where the fuel cap fits on.

I started the car and the Check engine light was still on, then I switched it off and waited for another 30 Minutes, then started the car again - Then the Check Engine Light was OFF

This shows that the O2 sensor fault code doesnt necessarily mean the O2 sensor is faulty, its mostly a symptom of an emission related malfunction such as a dirty fuel cap/inlet or a fuel cap not properly fitted.

@ Onwan

I have also read about the fuel tank cover thing, which makes me tighten it myself each time i refuel my car. I never did anything and when i told my boss at the office he was surprised, cos i parked after i came back from work and it was when i was going to the office that i noticed the CHECK light if no more there.

@Toba1909
Thats very interesting, BUT I know that IF it just gives a Check Engine Light and goes off by itself, something must have happened, maybe a mild reset from parking it for a while BUT what I found out is that the most common is the fuel tank cap.

@ Onwan,

I also find out from a member of a forum that when his vehicle shows the CHECK light indicator, all the diagnoses he did came out with no fault code or record. He said he took the vehicle to Toyota outlet where he stays, that they were unable to put off the light also.

That could be a problem with the Check Engine LED or something wrong with the brainbox (ECU). But it was very nice he did a scan though.

The major problem is not the diagnosing but the correct interpretation of the result. I bet an ordinary mech may not be able to give proper interpretation to the code cos they are all written in Technical Terms. Get the car scanned and lets see the CODES here, we will give you simple and professional way of getting the problem solved.

The unprofessional way i have seen the mechanics do is to remove/bypass the CEL light, the implication is that you will not be notified when there is another engine error.

Where is the location of your Car, i could send one of our Staff to help scan it and get the Car back in good shape professionally. Just call the Admin on 08035496482, or mail to lexyzs@yahoo.com

Thanx to all for your contributions.
@ Eastside Engr. the car is located in Delta state.
I was made to carry out some actions on the car,
1st i filled the gas tank, closed the fuel cap by mysef till it click, disconnected the +ve battery terminal for abt 5 minutes and reconnect. when i started the car this morning the Check Engine Light was gone.
While, i intend to keep an eye on it and communicate same.

Thanx very much,

@ ESEL- how do you resolve ABS & AIRBAGs issue on such cars- they seem straight forward than the check engine light. pls advice.

emytech:

Thanx to all for your contributions.
@ Eastside Engr. the car is located in Delta state.
I was made to carry out some actions on the car,
1st i filled the gas tank, closed the fuel cap by mysef till it click, disconnected the +ve battery terminal for abt 5 minutes and reconnect. when i started the car this morning the Check Engine Light was gone.
While, i intend to keep an eye on it and communicate same.

Thanx very much,

@ Emytech: You just did what was called the unprofessional shortcut. I bet u that if it is not an emission related problem that has to deal with the fuel tank cover, your ECU will detect the fault after you drive btw 50-80 miles again and trigger the check engine light. Your best bet is to still scan your vehicle and pull out the codes and know what to repair or change or maybe what to tighten, it could be a thousand and one things. Provision store better pass kiosk o! (Prevention is better than cure). All the best.

@ EMYTECH: Resetting the CEL approach you have just used is one of the unprofessional way. I trust the CEL light, it will be back knocking at your door some miles from now. Isnt there any professional auto shop there in Delta? Dont save a kobo to loose a Naira. Your Car i guess is precious to you.

@ KUNTASH: They seem straight forward cos they dont have much error codes as the MIL has. all the same, it still has to be diagnosed to detect the right fault.

Its simply easier to predict depending on the year model of your Car. Example, if the ABS of your Car is 2 Channel, then one will know that either of the 2 Channel is bad, so one could use physical inspection to know which is bad.
But if the ABS is 3 Channel, its pretty difficult and a scan will perfecly do to save time.

For the AIRBAG, its all about SAFETY. So, my advise is that , pls dont guess what the problem is. Just Diagnose and get the problem solved.

@Emytech
Im glad the fuel cap thing worked for you. What you also need to do is to always make sure its very clean and the inlet too, clean thoroughly to remove all dirts sticking on the rubber padding. Some people actually recommend changing the fuel cap after every 60k Miles.

Folks should pay attention to these whenever they have anything close to P0141, P0171, P0156, P0173 - It could be more than just these few codes though.

@ESEL
What the OP did was not "resetting the CEL" removing the battery OR not would have removed the Check Engine Light IF the malfunction is from an emmission related cause mostly from the fuel cap OR the fuel system hose/pipe.

By the way, let me correct you on one point; IT IS IMPOSSIBLE TO "RESET THE CEL", the CEL is simply an indicator of the ECU status, AND you cannot reset the ECU of a Camry by merely disconnecting the battery terminals (The manual reset procedure is way more complicated than that)

@ONWAN: Resetting the CEL light means to set something to zero (dictionary meaning) changing a reading to a different number. Here, it is applicable cos you want to change the indicator light to Zero. This mechanism uses a transducer and resetting is applicable here.

ESEL:

@ONWAN: Resetting the CEL light means to set something to zero (dictionary meaning) changing a reading to a different number. Here, it is applicable cos you want to change the indicator light to Zero. This mechanism uses a transducer and resetting is applicable here.

You have said your view and I respect that.

I am computer engineer and I know that the vehicle has a brain and thats the ECU, the Check Engine Light is simply an LED (a small bulb) with a plastic casing that has Check Engine written on it - that bulb only lights when the ECU detects a fault.

The ECU of that car however can be errased or reset using a diagnostic tool that has errase capability BUT NOT by just disconnecting the battery terminals for 5 minutes. So in effect the OP did not reset the ECU BUT solved the problem that caused the ECU to light up the Check Engine Indicator bulb/lamp - based on recommendations he got from Nairaland by experienced people.

The thing is, you need to understand he does not necessarily have to come to your shop to do the scan, and the funny part is that anyone who is educated enough to use a cell phone can use a diagnostic tool. The codes all have their interpretation in the Manual or the accompanying CD - those tools are about 35k for the average (detect-only) ones and that cost less than an average high end handset.

I personally will encourage car users who can invest 1M or above to buy a car to also invest about 10% to buy very good tools for troubleshooting. Im actually on the look-out for a used but well functioning Autoboss - it can actually calibrate airshocks on most vehicles and even set default values.

@ ONWAN:
Thanks for the idea. I wanted to include it in my last msg that i stand to be corrected. Anyway, i am pretty sure of something, we may often times be talking about same thing but the way we interpret may be quite different.
Thanks for being a Computer Engineer, i am not testing your field but, (smiles)
Also, i am not asking him to come to my office, (read the above msg again pls). The simple thing is getting something right in the right way. Trying to save a kobo might lead to loosing a Naira. In the first place, i only advised him not too guess what the problem is cos i know the light may be triggered by over 9,000 codes. So, how is he sure one of the error he guessed is the right one, out of over 9,000 chances. I am sure you did statistics back in the Uni.
I wish i can meet you personally to discuss better but still, on this note,

@ESEL

I appreciate your maturity and understanding. Car users should not be made to feel handicapped, BUT should be encouraged. Although some level of troubleshooting require advanced (and usually very expensive - Like Autoboss) diag. tools, thats why we have people like yourself in the business.

Actually if you look at my first post, you will see that it was that he should do a scan, and on time. BUT removing and washing or cleaning a fuel cap is one way to eliminate an O2 Sensor problem or an emission related issue (It could have been something else). I learnt this from people who had spent lots of dollars on diagnosis and sensors, only to find that a tight fuel cap or a clean fuel cap (or even a new one) would have saved them all that money.

I still have a professional grade unit for a give away price of N40k(trust me) with life data, and code definition

sultaan:

I still have a professional grade unit for a give away price of N40k(trust me) with life data, and code definition

Is it Autoboss though? Kindly give the name and model.

Actron 9145

Thats a very nice one; very flexible and easy to use, has a wider range of error codes and definitions than the one I have. Price is very okay too. IF OP had this, he would have scanned it in 2 minutes.

Its a good buy for any car owner.

Please let me know IF you have an Autoboss with a very good deal as you have with this one. Its capability to handle calibrations - airmatics, default value presets is very key for my kind of vehicles.

Mr ONWAN: I hope to meet you someday when i am back to Lagos.

That'd be nice.

Cheers

ONWAN: K, whats your chat id on Yahoo, pending my arrival

Its onwan1@yahoo.com

@ ESEL, tanks 4 ur response,

@Eastside and Onwan, thanx very much for your professional advice.

@ Sultaan, wats ur contact, am keen on having the Actron 9145