[driver242]

Hi,

The other day I thought I saw my check engine light come on, but when I looked again it wasn't. Then today, after driving for about 10 minutes it came on and stayed on. Later when I drove it again it was off the whole time, then then yet again later it came on for a short while.

Does anyone know what this might mean? Is it something simple (I hope) to fix?

Thanks!

 

[driver242]

more info

Whoops - also I have a 94 LS, with 124k on it. I haven't noticed any trouble with power or otherwise.

 

[Guest]

all i know about check engine lights is that you DON"T LET THEM GO... first time that happened to me my engine seazed (or ceazed however ya spell it)... i have no clue what it could be but just make sure it isnt anything like an oil leak...

 

[Mike 94PGT]

Read the codes out

Whoops - also I have a 94 LS, with 124k on it. I haven't noticed any trouble with power or otherwise.

Go to my web site (see sig) and click on "Malf Codes". Follow the directions there to read the code(s) out yourself. Likely, it'll be an O2 sensor code, being one or more of codes 15, 17, 23 and/or 24.

 

[Mx64u2catch]

You can do some self diagonistic readings from the computer you just haveto put a piece of wire in one of the slots for the fuse box i cant remmber wheere i will find out for you, but it sounds like o2 sensors did u ever change them???.

 

[driver242]

Got the codes

Ok, thanks for the tips - I did the paperclip thing and got 2 codes out of it:

16 and 24.

I've owned the car for just about 6 weeks, so I don't really have any history on it. Would this combination of codes mean anything? I'm looking throught the code list but I'm kind of lost as to what to do next.

Thanks!

 

[Mike 94PGT]

Re: Got the codes

Ok, thanks for the tips - I did the paperclip thing and got 2 codes out of it:

16 and 24.

I've owned the car for just about 6 weeks, so I don't really have any history on it. Would this combination of codes mean anything? I'm looking throught the code list but I'm kind of lost as to what to do next.

Thanks!

Before doing anything, disconnect the battery for a few minutes to erase the PCMs stored codes. Once this is done, wait for the CEL to come back on again. This will help verify the code is "real" and not some minor transient event.

If you get code 24 again, it's time for a rear (firewall-side, otherwise known as the "right") O2 sensor. Can be a bit dodgy to reach but there are Bosche direct-fit replacements available. An O2 sensor is a "maintenance" item that seems to need doing every 40,000 miles or so, on average, for the V6. Your car has two O2 sensors, one for the front ("left") bank and for the rear as well.

The code 16 is slightly more worrisome. If it comes back, it means either the EGR valve position sensor is shorted to ground or to Vref or the sensor is showing the EGR valve is at a position the PCM doesn't expect. Is the car completely stock? Do you have a cold-air intake on it? If so, what did you do with the little "vacuum" line that plugs into the back of the stock airbox? If that's not it, then you'll have to dig deeper, checking the EGR system vacuum lines, solenoids and maybe even replacing the sensor.

 

[driver242]

of course!

Thanks for all the help. I did that (cleaned the battery terminals while I was at it), and the codes are gone. I just drove it to get lunch (probably about 15 minutes drive time) and I haven't had the engine light come back on yet. I'll keep you posted!

 

[driver242]

<hr>The code 16 is slightly more worrisome. If it comes back, it means either the EGR valve position sensor is shorted to ground or to Vref or the sensor is showing the EGR valve is at a position the PCM doesn't expect. Is the car completely stock?
<hr>

The car is completely stock. At least, as far as I can tell. There are definately no obvious mods, and I'm pretty sure there's nothing hidden in there.

The previous owner, while quite the stereo fanatic, really didn't maintain the car all that well. Well, I should say that he does appear to have made regular oil changes, and if something broke he had it fixed, but beyond that there was really nothing done.

As such, I'm trying (learning) to go through a full maintenance schedule and get things on track. Since I have zero car experience, I'm at ground zero. I just changed the oil and filter last weekend (it took me an hour and a half, but hey, now I know how to do it), and I was going to try and hit the spark plugs and electrical system this weekend--but it looks like I may have a new project depending on this pesky engine light.

Anyway, thanks again!

 

[xeon]

Just as a preface before hitting the plugs and wires, pull the wires and make sure you don't have any oil on them. If so you need to replace the valve cover gaskets before new plugs -n- wires. Search valve cover gaskets in this forum and you will get plenty of info if you need it. On the rear plugs you have to have a long extension as the plugs are down a ways and you also need a sparkplug socket with a rubber ring in it, so you can get that rascal out of there.

 

[driver242]

new info from engine

Ok, after resetting the check engine data and driving home this evening, the light came back on and this time it was just the code 24. So hopefully the 16 was just an old fluke.

So, this, from what I gather, is the rear oxygen sensor? Is that going to be difficult to replace or is is pretty straightforward. It was hard to tell just looking at the sites and in my Hayes manual.

Also - is this something that I need to head over to the mazda dealer to get, or am I better off ordering from carparts, etc?

Thanks again!

 

[xeon]

You will get it cheaper from somewhere else besides the mazda or ford dealership. If you do order from carparts.com, make sure to pick up a coupon code at http://www.importhookup.com and don't necessarily expect it to show up pronto. They are cheap, but not always fast. You can wait though as a little more time with a code 24 won't wreck anything.