Check Engine Light - Help

I have limited mechanical experience. I change the oil, rotate the tires, and can change the spark plugs. I pay a mechanic to do just about everything else.

I purchased my 2003 Corolla new. I now have 110,000 miles on it. average around 32 mpg.

About 300 miles ago my check engine light came on. I took it to auto zone and they told me it was most likely the catalytic converter.

I took it to the Toyota Dealer and they told me that both air sensors were shot at well as the catalytic converter. In addition they said I needed a new intake manifold gasket. And after those things were done the cars computer would need to be updated. All this for about $2,000.

I found a shop in town that will do the catalytic converter and oxygen sensors for around $900.

Either way I don't have that kind of money now. My question is am I going to do any damage to my car if I run it as is for 3-6 months until I have the money to fix those items. I assume that the catalytic converter isn't going to damage anything. I don't know about the intake manifold gasket. I don't even know how they could tell it needs to be replaced.

Any thoughts would be greatly appreciated.

The actual code numbers would help greatly, but it is highly unlikely that the cat itself would go bad so quickly...and most emissions systems are required by federal law to be warrantied for at least 8 years (up to 10 for CA?). 5 years is way too early.

The federal emissions warranty covering 1995 and later vehicles includes a "performance warranty" that covers emission components that cause the vehicle to fail a state emissions test for two years or 24,000 miles, and a "design and defect warranty" that also covers "major specified emissions control components" for eight years or 80,000 miles. I think the cat and sensors both fall under this category, and both should last longer than the 5 yrs you have, but the mileage is the breaker in this case.

The oxygen sensors themselves could be the culprit, but would only set you back ~$150 to $200. Pricey, but they can be changed relatively easily by yourself, just be sure you get the correct part #s...bring the old ones in to match if you can.

Now if they see that there is oil coming from the top of the rear of the engine and that is why they recommend changing the intake manifold gasket I'd say stop. They MEAN the camshaft cover gasket which costs $20 for a set and can probably be done by yourself. Again, write down all the codes and compare them to the diagnosis to see if they jive.

I'd get an independent diagnosis before signing up to have the dealer do the work. Good luck!

I agree with jdm.......... Get the codes and check to make sure what you need. If its O2 sensors you can do the job yourself. Buy them from Auto Zone and have Auto Zone reset the codes after you are done.

the o2 sensors just unplug and screw out.if you can change a sparkplug then you can change an 02 sensor.

Thanks for the suggestions.

I have since taken the car in for a second opinion to an independent deal. They said the computer told them the check engine light was on for two reasons. In other words there were two error codes, which I wasn't able to get.

1. The fuel system was running to lean.
2. The catalytic converter

This shop suggested that I try and fix the first error, the fuel system running lean because it may possibly be giving a false error to the oxogen sensors or the catalytic converter.

Toyota suggested that I have a new intake manifold gasket installed. I have scheduled that in the hopes that it will fix one or more of the problems.

Any additional thoughts or suggestions would be appreciated. Thanks for the help so far.

Did the dealer just look at the engine and tell you the intake manifold gasket needed changing?

If so, take the vehicle to an independent and have them do a coolant pressure test.

Unless you actually see coolant leaking out from the gasket you can't diagnose it as a breached gasket.

My gut tells me somebody is trying to pad the bill, likely a service writer that doesn't have a clue.

Symptoms of a leaking intake manifold gasket include: a steady loss of coolant (quickly noticed via the reservoir), engine overheating, oily deposits in the coolant (check rad or reservoir), a light brown sludge on the bottom of the oil filler cap.

You won't see oil leaking from a blown intake manifold gasket.

the o2 sensors just unplug and screw out.if you can change a sparkplug then you can change an 02 sensor.

If your 03 is anything like my 02, be prepared for a real PITA job.
The front sensor is relatively easy, especially id you have small hands.
The rear sensor requires taking the interior apart because the sensor cable enters the vehicle just under the shifter. You have to take out the center console which includes the lower dash and the glove compartment.

The two O2 sensors are different.
Toyota requires both O2 sensors to be changed with a new cat.
I got mine on-line at substantial savings www.oxygensensors.com

Thanks to all who have offered suggestions.

I had the intake manifold gasket replaced. Then I requested that the check engine light be reset.

So far the light hasn't come back on. I've only driven about 100 miles since then.

If that fixes the problems it is frustrating to realize that the Toyota dealer was willing preform about $2,000 worth of repairs when its possible that only one of the items that they suggested might have fixed the problems.

On top of that they spilled oil on the serpentine belt and it began slipping. I had to take it off, clean the pullys, and put a new one on.

At the moment it looks like it will only cost $250 to fix instead of the $2,000 they first said. But I'm not a happy camper with my Toyota dealer experience. I like my Corolla, it's my fifth, but I wish the service had been better.