# Check Engine Light Went On...Then Off??



## Grug (Aug 20, 2009)

Any ideas why my CEL would come on and stay on for a coupla' weeks and then go off again?

Earlier, it had come on a couple of times this spring and both times I had turned it off by disconnecting the battery. A few weeks later it would come on again. 

But this time it went off by itself.

I'm not complaining as the truck works great...just curious.

My beast is a '97 4WD KA24.

In other news...I've posted enough to this forum to attain 'Fanatic' status. :woowoo:

Cheers!


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## GeoBMX4Life (Mar 25, 2010)

Could be some of that sea air/moisture in your ecu...thats all I can think...you FANATIC! LOL


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## zanegrey (Dec 5, 2005)

read the codes ...


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## Grug (Aug 20, 2009)

So even though the light is off...the code will still be stored in memory? Any idea how long? 

Since I'm OBII, I gotta' have someone read the codes for me. Too bad I didn't have an Auto Zone close by as apparently they'll read them for free.


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## Spinlock (Jun 12, 2006)

For the future, that light is there to tell you something's up, not to annoy you. Don't clear error codes by removing the battery cable!

As far as I'm aware, codes stick in the computer until they're cleared by a reader, but I may be wrong on that.


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## Grug (Aug 20, 2009)

I know, I know...I shouldn't be clearing codes with the battery. Something only a 'Fanatic' would do, eh?

Anyways, was talking to a fella' today that thought codes are automatically cleared after the next 50 full turns of the key (essentially, engine starts). Not sure if this is right or not. Was talking to another fella' who said his CEL has been on for almost 5 years! (Now I don't feel quite so bad).

And hey, Geo. You know the sweet, salty air you mentioned. You should see what it does over time to cars with no undercoating (doesn't help when the roads are covered with salt for 4-5 months of the year either).


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## GeoBMX4Life (Mar 25, 2010)

*LOL!!!*



Grug said:


> I know, I know...I shouldn't be clearing codes with the battery. Something only a 'Fanatic' would do, eh?
> 
> Anyways, was talking to a fella' today that thought codes are automatically cleared after the next 50 full turns of the key (essentially, engine starts). Not sure if this is right or not. Was talking to another fella' who said his CEL has been on for almost 5 years! (Now I don't feel quite so bad).
> 
> And hey, Geo. You know the sweet, salty air you mentioned. You should see what it does over time to cars with no undercoating (doesn't help when the roads are covered with salt for 4-5 months of the year either).


 HAHA...I had my truck undercoated in Calgary 6 months before moving to Montreal...and the guy that did the undercoating didn't understand WHY I was getting it done when I was in AB...AB uses way less salt than PQ...I had team mates in Montreal that had 4 year old rust buckets...and I imagine its the same deal out there!


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## smj999smj (Jan 1, 2006)

On 97's, you can access the codes via the ECM mode screw on the ECM itself, putting it into Mode II Self-diagnostics, however it is a lot easier to use an OBDII code reader. Most parts stores will do this for free, or you can buy a fairly inexpensive code reader at most parts stores or Wal-mart, in the automotive section. 

The light will turn off if it doesn't see the problem trigger in two consecutive trips. However, it will not erase from the ECM memory until it sees 50 trips made without the code re-occuring (not 50 ignition cycles, as mentioned). A trip consists of a number of parameters that the ECM sees while the vehicle is operated, similar to those seen in an IM240 emission test.


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## Grug (Aug 20, 2009)

Hey there, smj, thanks for the insight.

I'll call around and see if any local parts stores will read the codes. I've seen garages advertise that they'll read the codes for $25.00. The cheapest I've seen one to purchase is around $150.00.

I suppose this whole thing could be as simple as a gas tank cover not seated correctly (although I'm pretty good at making sure the cover snaps a coupla' times after a fill up).

Not too sure what an IM240 emission test consists of. I do know that here in Nova Scotia we don't have to have emission tests done on vehicles (not yet anyway). Every two years they must have an MVI (motor vehicle inspection) but no smog tests.

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And hey Geo, what did you use for undercoating? Fella' that sprays mine uses a cocktail of chainsaw bar oil and candle wax. Makes for an awful mess, but it does the trick. He fills the doors, fenders, tailgate...wherever he can get it. The truck will drip for days after an application (gotta' be careful where I park it).


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## saudade (Apr 10, 2010)

I realize you live in NS, but cheap code readers can be had all over eBay (Ebay.CA), and other online sites. I realize the taxes raise the cost but you may find one from someplace in CA, you may be spared them.

Here's one example of a decent one closing in a few hours that's still at a reasonable price (at the time i posted this)

Professional SUPER CAN OBD2 OBD II Code Scanner /Reader on eBay.ca (item 310245485969 end time 29-Aug-10 12:30:00 EDT)


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## Grug (Aug 20, 2009)

Hey there, saudade. Yeah, I actually use e-bay a lot, but I'm a little nervous of buying anything on e-bay that's electronic. I got burned twice before (digital memory cards and a digital movie camera). Got my money back, but it was a major hassle making everything right.

That being said, perhaps I'll poke around a little more.

Thanks for the suggestion.


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## smj999smj (Jan 1, 2006)

I bought one in Wal-mart for $65 US. It's nothing fancy, just reads and erases codes. I keep it in the glove box and it comes in handy. Beats carrying around the shops $3000 OTC scantool!


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## GeoBMX4Life (Mar 25, 2010)

*Not sure*



Grug said:


> Hey there, smj, thanks for the insight.
> 
> I'll call around and see if any local parts stores will read the codes. I've seen garages advertise that they'll read the codes for $25.00. The cheapest I've seen one to purchase is around $150.00.
> 
> ...


 I'm not sure what the exact compound was, but it was a foam that was sprayed into the doors, and a spray for the under carriage. My truck just started to show some rust a few years ago.


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