CEL on my "new" '99

I drove my NB into work today and the freakin' CEL light came on. :? Stayed on solid, not flashing. I just did some reading on the pointy board and it looks like it could be plugs, wires, and/or coil issues.

Some of y'all saw how ugly the plugs in the car are, and I've got plugs and wires coming from Mazdaspeed Motorsports. Everything else looked good gauge wise (temp, oil pressure), but the idle was up and down like a yo-yo. Ran great once I started moving though. :D

Anyone have a code reader, or should I drop by Vatozone?

Thoughts, comments, suggestions?

Sounds like a bad coilpack? I think there is a TSB out on the '99 coilpacks, so you might be able to get some assistance from Mazda on that one.

Then again, it might not be. My '99 has the original coilpacks at 92k miles, and the only problem I have is the occasional stumbling idle when its cold, but it's never thrown a CEL for it.

Doesn't it run bad if it's a coil pack failure?

Dunno. I've never had a problem with mine, so I've never done the research on it. I just know I've heard coilpack problems and a TSB alluded to in the NB section on the pointy board on occasion.

just had an odd code on my car pop up- "EGR circuit, temporary fault"

cleared it and haven't thought about it again.

if your in Ft. Worth, i can get it scanned for ya. the BMW shop i was working for lets me use their scanner when i need it. it is VERY comprehensive, adn doesn't just display a fault code- it gives the definition, number of times the fault was recorded, and lets you know if it's an active fault or just one stored from a random hickup in the obd logging.

Take it to AutoZone Sammm and let us know what ya get!

Those plugs did look tired!

By the way, Sammm - you may already be aware of this, but the oil pressure gauge in a '99 is a glorified idiot light. As long as you have even minimal oil pressure, the needle will move to about halfway and never budge.

If you ever see that needle start to fall, the damage has already been done. :(

I had the coil pack issue at my first autoX. Hiley replaced the plugs, then wires, then the cat, then finally found the prob with the coil pack. Later they replaced the cat again, since the coil pack issue ruined the new cat. But no probs since. The good thing- Hiley (arlington) did all this work under the Emissions Warranty- something like 80K miles. I never paid a dime.

I would unhook the battery cable for a few minutes to 'reset/erase' your codes and then try it again- to see if you get the same code right away.

The car will run on a couple cylinders when the coil pack goes bad. My car would reset itself and run fine for a day or so before throwing the code again.

Just got back from Autozone. Code is a P0420.

"The PCM has determined that the catalyst efficiency for bank 1 is below threshold for the current engine operating conditions"

The little troubleshooter book for the reader mentions the cat as first probable problem, plugs/wires are second. It seems to be idling smooth again, but the light remains on. I re-seated on of the wires on the coil-pack that seemed to be loose.

Should I call Mazda?

I'd put new plugs and wires on it before I took it into the dealer, that way you can help them eliminate some of the possibilities. :wink:

I disconnected the battery to reset the computer. The CEL is out and has not come back on (yet). I went to get it inspected, but it failed because of 4 "Not Ready" messages. One each for the catalyst, Evap, O2 Sens and EGR Sys.

The guy said if the battery gets disconnected, it takes 50 miles or so before the computer is re-loaded with all the drive info. 2 "Not Ready" is OK. 4 is failed inspection. It's still idling smooth.

Joe M., how intermittent was your problem?

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Originally Posted by sammm

Just got back from Autozone. Code is a P0420.

"The PCM has determined that the catalyst efficiency for bank 1 is below threshold for the current engine operating conditions"

The little troubleshooter book for the reader mentions the cat as first probable problem, plugs/wires are second. It seems to be idling smooth again, but the light remains on. I re-seated on of the wires on the coil-pack that seemed to be loose.

Should I call Mazda?

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That is the code I kept getting prior to total coil pack failure. It may be in the process of going bad....to the point of damaging the cat, but not total failure yet.

My prob ocurred once a week, then began to occur more often- until failure.

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Originally Posted by sammm

I disconnected the battery to reset the computer. The CEL is out and has not come back on (yet). I went to get it inspected, but it failed because of 4 "Not Ready" messages. One each for the catalyst, Evap, O2 Sens and EGR Sys.

The guy said if the battery gets disconnected, it takes 50 miles or so before the computer is re-loaded with all the drive info. 2 "Not Ready" is OK. 4 is failed inspection. It's still idling smooth.

Joe M., how intermittent was your problem?

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When my 97' Civic was throwing the CEL light, the emissions tester, told me I had to drive 80 or so miles, but also said to wait 48 hours before bringing it back to test again!

We just tell people to drive it 6 times or so, 50-100 miles is ok. See, if you drive it 6 times, you start it 6 times, it drives 6 times, it cruises 6 times, etc etc., the sensors are given a chance to make sure that the "normal" operation specs are being read correctly. Usually, this method does work in clearing codes. Occasionally, there is a car that takes a little longer. It would be nice of the inspector if he plugged your car in as a Diagnostics check before carrying out the Re-inspect.

I forgot about the emissions warranty. Even though the bumper-to-bumper coverage on that car is long gone, if the problem is interfering with the car's emissions system, it should still be covered.

At least we can thank the EPA and Uncle Sam for one thing... :roll:

After approx. 25 miles since disconnecting the battery, the CEL is back on. Still running OK. Idle OK too.

I guess I'll call the seller tomorrow and see what he says about it. I don't think he can complete the sales transaction with the state until he has the proof of inspection, and that ain't gonna happen with a CEL on!

After I get the new plugs and wires installed, I'll reset the computer again.

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I'd put new plugs and wires on it before I took it into the dealer, that way you can help them eliminate some of the possibilities.

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I agree. Replace the plugs and go from there. Good Luck.

Don't look at this as a bad omen. This simple failure might be why the original owner sold it. His loss will be your gain :wink:

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Originally Posted by TurboDuane

Don't look at this as a bad omen. This simple failure might be why the original owner sold it. His loss will be your gain :wink:

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Well said TurboDuane! :afro:

My new plugs and wires are supposed to be delivered today. Once I install them, is it possible to manually 'erase' the P0420 code? If so, can I then get it inspected, or will it fail because of a 'Not Ready' condition? Anyone know how that works? :scratch:

Thanks in advance!

Quote:

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Originally Posted by sammm

My new plugs and wires are supposed to be delivered today. Once I install them, is it possible to manually 'erase' the P0420 code? If so, can I then get it inspected, or will it fail because of a 'Not Ready' condition? Anyone know how that works? :scratch:

Thanks in advance!

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The 2 ways I know:

1. un-hook the battery.
2. Talk the kid at AutoZone into looking the other way while you fiddle with the code reader to find the 'CLEAR' button. They are not 'allowed' to clear any codes, but you can if you can get hold of the device.