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Malfunction indicator light on the dash came on
Posted: Sun Jan 18, 2015 8:39 am
by bkcheong
Not sure if it is my fault or pure coincidence, but today, my car did not start on the first push of the starter button. It sounded as if the battery was flat. I then tried it for a second time ( without waiting for the recommended 15 seconds interval) and it still failed to start. In fact, the engine did not even crank over. I tried for the third time and behold, it started! But now, I have the malfunction indicator light staying on on the dash. Checking the manual, it says the emission control might need to be serviced or there's a problem with the continuously variable transaxle.
Just wonder if anyone has had their malfunction indicator light staying on and what you did to fix the problem.

Re: Malfunction indicator light on the dash came on
Posted: Sun Jan 18, 2015 10:44 am
by Woodie
Could be hundreds of different things, literally. That light basically means "something is wrong". Take it to a dealer.
Here in the States, some auto parts stores will read the error codes for you in the hope that you'll buy parts from them to fix it. But if you don't know much about it, then that information isn't going to do you any good.
Re: Malfunction indicator light on the dash came on
Posted: Tue Jan 20, 2015 4:14 am
by KuroNekko
As Woodie wrote, the Check Engine Light (CEL) goes on for a bunch of different reasons. A bad start like you had can set it off. I've had that happen in a previous car.
You can take the car to have the "code read". Basically, whenever a CEL comes on, the car's computer sets off an error code that can be read by a mechanic with the right tool plugged into the vehicle's OBDII port. The code then tells the mechanic which sensor or vehicle component system is faulty.
Re: Malfunction indicator light on the dash came on
Posted: Tue Jan 20, 2015 11:21 am
by Woodie
KuroNekko wrote:The code then tells the mechanic which sensor or vehicle component system is faulty.
Well, that's a bit wishful. The code reports where the computer perceives a problem, there's often still quite a bit of troubleshooting involved with narrowing it down to the exact problem.
Re: Malfunction indicator light on the dash came on
Posted: Tue Jan 20, 2015 11:58 pm
by KuroNekko
Woodie wrote:KuroNekko wrote:The code then tells the mechanic which sensor or vehicle component system is faulty.
Well, that's a bit wishful. The code reports where the computer perceives a problem, there's often still quite a bit of troubleshooting involved with narrowing it down to the exact problem.
It depends on the code. Sometimes, it's very specific and that's usually when it involves a specific sensor failure. I've personally read codes that identified which 02 sensor on which bank was faulty on a V6 Camry.
Other times, it's far more vague and will indicate a problem with a certain component system, but as you stated, requires the mechanic to perform tests to properly diagnose what the culprit is.
I have an OBDII Wifi device and a smartphone app that works as a CEL reader and it has helped me resolve a number of issues for various cars. I find that sensor failures tend to throw very specific error codes.
Re: Malfunction indicator light on the dash came on
Posted: Wed Jan 21, 2015 12:04 pm
by Woodie
KuroNekko wrote:It depends on the code. Sometimes, it's very specific and that's usually when it involves a specific sensor failure. I've personally read codes that identified which 02 sensor on which bank was faulty on a V6 Camry.
That's a perfect example, P420 means 'bank 1 oxygen sensor 2" is reporting that the catalytic converter isn't working well. It could be that the O2 sensor is bad, the wiring going to the O2 sensor is bad, the catalytic converter is bad, you got a replacement exhaust made at Midas and they put the O2 sensor in the wrong place, your engine is worn out and cat isn't getting hot enough to fire off...............
Another good example is the one for vapor recovery system leak. It's usually that you didn't tighten the gas cap but no one tells you that until you're stood in front of the $90 an hour mechanic.
Re: Malfunction indicator light on the dash came on
Posted: Thu Jan 22, 2015 12:29 am
by bkcheong
Thank you for your comments, guys.
Well, the malfunction indicator light was triggered by the battery which was a bit low on charge. This was the factory battery, so it's just over 4 years old. Apparently, when the car is starting and it senses a drop in the voltage whilst starting, it triggers the light. And I was told it has to be reset by the dealer (free of charge, I might add).
Anyway, I'm glad it wasn't anything serious.
Re: Malfunction indicator light on the dash came on
Posted: Thu Jan 22, 2015 2:12 am
by KuroNekko
Woodie wrote:
That's a perfect example, P420 means 'bank 1 oxygen sensor 2" is reporting that the catalytic converter isn't working well. It could be that the O2 sensor is bad, the wiring going to the O2 sensor is bad, the catalytic converter is bad, you got a replacement exhaust made at Midas and they put the O2 sensor in the wrong place, your engine is worn out and cat isn't getting hot enough to fire off...............
Another good example is the one for vapor recovery system leak. It's usually that you didn't tighten the gas cap but no one tells you that until you're stood in front of the $90 an hour mechanic.
A P420 is often a bad O2 sensor. In fact, I just read that code on a VW Jetta a few months ago and replaced the O2 sensor. Cleared the CEL and it hasn't come back. However, I agree that in many instances, it's not specific and there are diagnostics that have to be done to properly identify issue.
bkcheong wrote: And I was told it has to be reset by the dealer (free of charge, I might add).
It doesn't
have to be reset by the dealer. Disconnecting your battery will clear the CEL though the code may be stored. Many mechanics can read and clear these CELs. Heck, I have a device and app that does it. However, if the dealer will do it for free, you might as well take them up on it.
Re: Malfunction indicator light on the dash came on
Posted: Thu Jan 22, 2015 11:25 am
by Woodie
Doesn't need to be reset at all. After 40 or so (varies according to which code) warm up cycles without a fault, the codes clear themselves.