check engine light code

The check engine light has been on on my '99 Miata for more than a year. The guy at the Shell station was nice enough to check the code for me, but the dealer won't tell us what the code means. Does anyone out there know what P1135 error code indicates? Much appreciated. -- Anna

I'm insanely proud to report that I answered my own question. And I want to turn everyone else on to the way I did it: If you go to www.obdii.com/codes.asp, you can enter the make of the car and the code (in my case P1135), and it will spit out exactly the cause of the error code. Mine was the heated oxygen sensor. The beauty is that I didn't even have to call the dealer to get this information, and can instead keep in business the handsome, affable Greek guy down at the corner service station! - ako

I'm also having trouble with the check engine light going on and off - sometimes the engine isn't running well, sometimes it is. The code the service folks get is "random misfire" and can't seem to find the cause of it. Anyone have any clues?

I went to that website and it doesn't offer anything for miata only for domestic cars?

I'm also having trouble with the check engine light going on and off - sometimes the engine isn't running well, sometimes it is. The code the service folks get is "random misfire" and can't seem to find the cause of it. Anyone have any clues?

What year is your Miata? The 1999-2000's had a batch of bad coil packs (the ignition coils that the spark plugs connect to.) It is easy to replace yourself, but costs about $220. If you let the problem go on too long it will destroy your catalytic converter.

How does one know what the code is? Does it take a mechanic, diagnostic equipment etc. Sorry - I'm not to savvy with cars, but my engine light goes on for a few days about once a month. So far I have just ignored it because it soon turns itself off again.

My 1999 Miata check engine light stays on all the time. If the code is reset the light stays off for a few days and then returns. Autozone says it is a problem with the EGR valve. I removed the valve to check for carbon build up and clean it. Reset the codes by disconnecting battery. Of course the light came back on after 3 days. But long enough to pass emissions test!! Anyone heard of problems with the EGR? They are $250, I would like to avoid buying a new one. Sometimes the car will idle rough thought it might be related to the coil problem described in the other post. Any connection to the EGR?

I got 2 codes today I just pulled. They are P0303 and P0420. The P0303 says cly. 3 misfire detected. The P0420 says catalyst effeciency below threshold (bank 1). Could this be a bad coil pack and that is what's making the 420 code pop up?

Bill4, your codes are exactly what happens when the coil pack is failing. If the rough running continues it will wreck the catalyst, that is what causes the P0420 code.

If changing the plug wires does not fix the problem, you probably need a new coil pack. The part is expensive (around $230) but is not difficult to change. This should fix the misfire problem. However, if the 420 code remains you may need to have the catalyst replaced. Fortunately this is a covered part under the 80,000 mile emissions equipment warranty.

Hey thanks, I did get the coil pack today. Going to install it in a few. Also, thanks for the heads up on the 80,000 mile warranty on the catalyst.

Before I installed the ignition coil pack, I bought a set of NGK wires for it. And, that was the problem. Luckily I was able to returm the coil pack. Thanks for all the help.

If the coil pack is bad, wouldn't the ecu code show two misfiring codes? Isn't there dual coil on the miatas? I think it is a single unit, but has two coils.

youll get p0300 for a coil going bad, it is a two plugs per coil setup.. when the pcm detects more than 1 misfire it throws a "random misfire" code p0300.

I have a 99 miata which had to have cat replaced (ECU P0421). Just bought it..... The dealer asked me if I had any misfire problem, which probably caused the cat to go bad. They suggested that I get new coil pack ~$400 replaced. I talked to the previous owner, and he told me that he had problem last year (running really rough) where he had to replace crankcase position sensor ($350). Could CPS have been the problem? Should I be worried and replace the coil pack? I know that 99 supposedly had faulty coil pack, but replacing something that works well for ~400 is stupid. What percentage of the 99 had bad coils? Why isnn't Mazda recalling coil pack like they did with the Protege?

My 1999 Miata check engine light stays on all the time. If the code is reset the light stays off for a few days and then returns. Autozone says it is a problem with the EGR valve. I removed the valve to check for carbon build up and clean it. Reset the codes by disconnecting battery. Of course the light came back on after 3 days. But long enough to pass emissions test!! Anyone heard of problems with the EGR? They are $250, I would like to avoid buying a new one. Sometimes the car will idle rough thought it might be related to the coil problem described in the other post. Any connection to the EGR?


I have a 1999 and last year I had the local guy check to code and said he had to change the EGR sensor, it was good for a few 100 miles and the lihgt flashed on again, but like yours when it is off or on it runs really well but when it flases it feels like only have the engine is working. anyone with ideas?

Ken Downs it's not your egr valve that is bad or clogged. It's the egr ports in you intake that are clog and causing the egr boost senor(map sensor ) to throw
that code it should be a p0400 / p0401 / p0402 egr flow code. you have to take the throttle body off and the upper intake off and clean a port need the front of the intake on the upper intake. Highly recommend you save some money and take it to the Dealer (DO NOT TAKE TO AN INDEPENDANT SHOP) they don't know what to do. After that is down you should use better gas and do a top engine clean once in a while to avoid this pricy repair.

the code p1135 is for o2 sensor I don't remember which one it is.

I have a 99 miata which had to have cat replaced (ECU P0421). Just bought it..... The dealer asked me if I had any misfire problem, which probably caused the cat to go bad. They suggested that I get new coil pack ~$400 replaced. I talked to the previous owner, and he told me that he had problem last year (running really rough) where he had to replace crankcase position sensor ($350). Could CPS have been the problem? Should I be worried and replace the coil pack? I know that 99 supposedly had faulty coil pack, but replacing something that works well for ~400 is stupid. What percentage of the 99 had bad coils? Why isnn't Mazda recalling coil pack like they did with the Protege?

Hi,

The crankshaft position sensor tells the ECU to position of the crankshaft (hence the name :-)) This is how the engine timing is controlled. If it goes bad, the engine timing could be off. Not sure how off it would have to be to cause damage to the catalytic converter.

Anthony

it control ignition timing and fuel. it could cause the car to run rich or fuel flood whitch cause the cat to melt internally by having fuel in it.

oh yeah it could cause miss fires which make it run rich due to unburnt fuel.

just be careful not to spill rice into the intake........
right chubby?

My Check engine light won't go off on my Miata 1999. I see everyone having trouble, but mine is the code for the Heated O2 Sensor, which I REPLACED (not cheap). Now its on and off, and i have the SAME obdii code for the O2 sensor, what do i do??? I LOVE my miata (new to me) but when that engine check light is on, my car runs like crap, when its off, it's great. NO other codes are showing up. help! email me if u can @ [email protected]!

I have the same problem. Error code P1135. Dealer told me front O2 sensor needs replacement ($350 dealer quote). Bought sensor over Internet and installed yesterday. Did reset check engine light (disconnect battery). Light came on after about 10 miles driving.
Any suggestions???? Thanks

I have the same problem. Error code P1135. Dealer told me front O2 sensor needs replacement ($350 dealer quote). Bought sensor over Internet and installed yesterday. Did reset check engine light (disconnect battery). Light came on after about 10 miles driving.
Any suggestions???? Thanks
==> I recently had exactly the same situation on a 2000 Miata. Same code. Replaced the front O2 sensor with OEM Mazda part. The engine light was off for 30 miles, but came on again the next day. What was the subsequent outcome in your case? Thanks in advance.

I have a '99 Miata that has the same problem too. The CEL comes on, showing P0420 - I reset it and within a day or two the light comes back on with the same code. I've replaced both O2 sensors with no change in behavior. I've also cleaned the MAF sensor (recommended by some other boards), but that hasn't made any difference either. I'm about ready to give up.

My 01 started the CEL right after a oilchange at Midus, their computer doesn't show any error, but the dealer scan came up with a code of P0037. I would have to pay $92.50 to know from them what that transalts over to, anyone here have a clue? Thanks for the help.

99 Miata...engine light off and on frequently. Have had catalytic converter replaced twice, and recently had coil pack replaced. Now, light is on again. It used to run very rough and light come on at startup (probably coil pack fixed that). Now light came on while driving down the road. Any suggestions? Thanks guys...I'm a girl, so really need some good advice...it's been an expensive year, but I love my Miata (my 3rd)!

99 Miata...engine light off and on frequently. Have had catalytic converter replaced twice, and recently had coil pack replaced. Now, light is on again. It used to run very rough and light come on at startup (probably coil pack fixed that). Now light came on while driving down the road. Any suggestions? Thanks guys...I'm a girl, so really need some good advice...it's been an expensive year, but I love my Miata (my 3rd)!


I would take it to an autozone parts store and get them to see if they can pull a code on it. With that code you can do a search on the net as well as a pervious poster has a link to read what the code means. The store should be able to tell you what it means as well. IT could be a loose wire or a bad part so get code and what it means and go from there
Just because you are a girl and not a girly girl you may can do the repair your self. If not look for a miata club in your area to help you

I would take it to an autozone parts store and get them to see if they can pull a code on it. With that code you can do a search on the net as well as a pervious poster has a link to read what the code means. The store should be able to tell you what it means as well. IT could be a loose wire or a bad part so get code and what it means and go from there
Just because you are a girl and not a girly girl you may can do the repair your self. If not look for a miata club in your area to help you


thanks. Will do that.

thanks. Will do that.


Please come back and let everyone know what it was and how it got fixed did you do it a shop do it or you foiund a club.
It is sad never know what the end result was :crying: