Check Engine Light: Take or To Not Take In

[axelfox]

Last month I had my starter & alternator replaced. The check engine light was on.

The check engine light is still on about 99% of the time. Last night and today, it was off.

Should I still take it in?

UPDATE 1/17:

1998 Toyota RAV4, 4 Dr 2wd
I went into AutoZone and borrowed their code reader. Here are the results:

P0401 EGR FLOW INSUFFICIENT

For the IM MONITORS, all OK except:

HTD Catalyst n/a
Sec Air System n/a
A/C Refridgerator Mon n/a

Thoughts?

UPDATE 1/18:

I think I found the EGR Valve, but it may be a pain to get into. It's on top rear of the engine, close the firewall (?). I don't know if I can get my hands there, let a along fit a wrench.

UPDATE 1/23:

I got the tools, but I am unable to remove two of the nuts securing the EGR valve. On one of the nuts, I can't even get a tool there. Dang, that means I have to take it in.

 

[CoachB]

My first step would be to take the car by an Autozone, O'Riellys, or such and ask them to run a scan to see what is causing the light to burn. Sometimes it can be something relatively easy to fix. The scan is usually free.

 

[flyguy214]

Originally posted by: CoachB
My first step would be to take the car by an Autozone, O'Riellys, or such and ask them to run a scan to see what is causing the light to burn. Sometimes it can be something relatively easy to fix. The scan is usually free.

Autozone is awesome about doing this kind of thing.

 

[sniperruff]

pep boys in queens, NYC wanted to charge $20 for it. bastards.

 

[lurk3r]

Originally posted by: sniperruff
pep boys in queens, NYC wanted to charge $20 for it. bastards.

Yeah, because all services should be free, how unfair of them to charge you for providing a service.


Seriously search online and see if there's a way to do the key dance (turn your key on and off several times and the light will blink with error codes). All my old dodges used to do the blinky key dance, and you could at least figure out what the compuiter thought was wrong. A make and model would help.

 

[T2urtle]

post year make model engine of car and fault codes from autozone when u get a chance, from there we can tell u if its an easy fix or not.

 

[SoulAssassin]

Originally posted by: lurk3r

Originally posted by: sniperruff
pep boys in queens, NYC wanted to charge $20 for it. bastards.

Yeah, because all services should be free, how unfair of them to charge you for providing a service.


Seriously search online and see if there's a way to do the key dance (turn your key on and off several times and the light will blink with error codes). All my old dodges used to do the blinky key dance, and you could at least figure out what the compuiter thought was wrong. A make and model would help.

$20 for sending a guy making $6/hr out to your car for 5 minutes with a device that's long since been paid for seems a little excessive. Autozone does it right, they'll do it for free and then conveniently print out a summary of the problem along with the cost of the parts to fix it which they will be glad to sell you for a profit.

 

[imported_hopeless]

Originally posted by: axelfox
Last month I had my starter & alternator replaced. The check engine light was on.

The check engine light is still on about 99% of the time. Last night and today, it was off.

Should I still take it in?

If it isn't running any different. The first thing I'd do is unhook the battery for a few minutes to give the computer time to "forget". Then hook the battery back up and drive normally. If it comes back on then find out what the code is by the advice above.

 

[T2urtle]

Originally posted by: hopeless

Originally posted by: axelfox
Last month I had my starter & alternator replaced. The check engine light was on.

The check engine light is still on about 99% of the time. Last night and today, it was off.

Should I still take it in?

If it isn't running any different. The first thing I'd do is unhook the battery for a few minutes to give the computer time to "forget". Then hook the battery back up and drive normally. If it comes back on then find out what the code is by the advice above.

that only works with the older cars. pre OBDII which is 96 and older.

Now a days when you do it. the light goes off but is still stored in the computer and a scan tool will be able to pull it out or say emission testing places will fail you as well.

 

[JulesMaximus]

I wouldn't just ignore it. Those things go on for a variety of reasons but it should never be ignored.

 

[alfa147x]

Originally posted by: SoulAssassin

Originally posted by: lurk3r

Originally posted by: sniperruff
pep boys in queens, NYC wanted to charge $20 for it. bastards.

Yeah, because all services should be free, how unfair of them to charge you for providing a service.


Seriously search online and see if there's a way to do the key dance (turn your key on and off several times and the light will blink with error codes). All my old dodges used to do the blinky key dance, and you could at least figure out what the compuiter thought was wrong. A make and model would help.

$20 for sending a guy making $6/hr out to your car for 5 minutes with a device that's long since been paid for seems a little excessive. Autozone does it right, they'll do it for free and then conveniently print out a summary of the problem along with the cost of the parts to fix it which they will be glad to sell you for a profit.

If you feel better pay the free one $0.58

 

[ViviTheMage]

oxygen sensor maybes?

get it read.

 

[axelfox]

Thanks for the replies. I'm going to take it in and have it checked.

 

[Crucial]

Originally posted by: hopeless

Originally posted by: axelfox
Last month I had my starter & alternator replaced. The check engine light was on.

The check engine light is still on about 99% of the time. Last night and today, it was off.

Should I still take it in?

If it isn't running any different. The first thing I'd do is unhook the battery for a few minutes to give the computer time to "forget". Then hook the battery back up and drive normally. If it comes back on then find out what the code is by the advice above.

Why not just get the codes read and then do the battery. Why put it off when it already threw a code for something?

 

[axelfox]

I went into AutoZone and borrowed their code reader. Here are the results:

P0401 EGR FLOW INSUFFICIENT

For the IM MONITORS, all OK except:

HTD Catalyst n/a
Sec Air System n/a
A/C Refridgerator Mon n/a

 

[CoachB]

I would google each of those results but it looks like you have a bad EGR valve. Those are usually easy to replace and relatively inexpensive. I think the other stuff is just reporting that no reading is available for those sensors.

 

[BaDave]

egr=exhaust gas recirculation.it is a valve that usually under decel. will open an allow exhaust gases to be reburned.for some reason it is not opening enough or the valve is not working at all.the ports could also be plugged.

 

[fuzzybabybunny]

Originally posted by: T2urtle

Originally posted by: hopeless

Originally posted by: axelfox
Last month I had my starter & alternator replaced. The check engine light was on.

The check engine light is still on about 99% of the time. Last night and today, it was off.

Should I still take it in?

If it isn't running any different. The first thing I'd do is unhook the battery for a few minutes to give the computer time to "forget". Then hook the battery back up and drive normally. If it comes back on then find out what the code is by the advice above.

that only works with the older cars. pre OBDII which is 96 and older.

Now a days when you do it. the light goes off but is still stored in the computer and a scan tool will be able to pull it out or say emission testing places will fail you as well.

Not always true. If you disconnect the battery and flush the system of any remaining electricity, like by using the horn or pressing the brake for the brake lights, the code will clear.

However, there will be a Readiness Code that is stored in the computer indicating to any scan tool or emissions test place that certain emissions control components of the car have NOT been self-tested. If you take the car directly to the emissions test center after clearing the code five minutes before, it will fail due to this code. To get rid of this you need to give the car time to complete its self tests.

After clearing the code... Drive the car in stop and go traffic. Cruise the car at highway speeds. Idle the car. Accelerate the car. And drive with the air conditioning on for a bit for good measure.

I did this exact same thing because my car has had a check engine light for a year, and I was up for my E-check that I would fail if I didn't get the code cleared. Did the battery disconnect thing, cleared the light, did the driving to give the car a chance to do its self test, passed the emissions test, then the check engine light came back on 10 miles later.

 

[T2urtle]

that fault means mainly that the EGR valve most likely be clogged with carbon build-up.

but check these out. a EGR valve normally looks like a DISC about the size of a pop can. can it plastic sometimes but more often made of metal and shiny. it in on top of the engine most of the time. But it will be near the throttle body. There should a vaccum line to it. often times they dry rot thru and cause lack of vac, which in return causes poor EGR flow.

Most of the time the EGR valve is held on by 2-4 bolts. unbolt it and check out the vavle itself and the metal lines as well see how much carbon build up it has. try to clean it out. Or you can just replace it, they are in the upper $100.

dealership wise should run you 100$ diag, on what you already know. and then most like near 200 for the part and 150-250 to replace it.

 

[DougK62]

EGR valve may not be bad, maybe just carbon build-up. Some cars are extremely prone to this happening and throwing codes. Take it off and clean it good before replacing. They can be expensive to replace for certain vehicles.

 

[axelfox]

UPDATE 1/18:

I think I found the EGR Valve, but it may be a pain to get into. It's on top rear of the engine, close the firewall (?). I don't know if I can get my hands there, let a along fit a wrench.

 

[axelfox]

UPDATE 1/23:

I got the tools, but I am unable to remove two of the nuts securing the EGR valve. On one of the nuts, I can't even get a tool there. Dang, that means I have to take it in.