How to diagnose MIL code.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Sat Nov 20, 2010 6:51 pm

I know with the Neon, you put the key in, turn it "On" - "Off" like 4 times or something... and it'll spit the code out on the Odometer portion of the cluster. And then, if I remember correctly, the 1GN's did a morse code kinda beeping at you.

Anyhow, my wife has a 2000 Saturn SL2 and her MIL is on. I figured that if the Neon's had a way to show the code without having to go somewhere, that another type of vehicle might have a way also... does anyone happen to know how, if possible, for the Saturn?

Thanks

sidepipe87 · Post by **sidepipe87** » Sat Nov 20, 2010 7:58 pm

nope. don't think it's possible. you need an OBD2 scan tool probably.

JeffM · Post by **JeffM** » Sat Nov 20, 2010 8:37 pm

Neons are the only car I know of that actually shows the code.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Sat Nov 20, 2010 8:54 pm

Very interesting. Well, thanks!

sidepipe87 · Post by **sidepipe87** » Sat Nov 20, 2010 9:03 pm

JeffM wrote:Neons are the only car I know of that actually shows the code.

Chryslers. Not just neons.

Post by **occasional demons** » Sat Nov 20, 2010 9:40 pm

There is a way with a paper clip on the older GM products, but I can't recall which pins were jumped, and it may only be for pre '96.

nicksdad06 · Post by **nicksdad06** » Sat Nov 20, 2010 10:51 pm

autozone

Post by **racer12306** » Sat Nov 20, 2010 10:54 pm

occasional demons wrote:There is a way with a paper clip on the older GM products, but I can't recall which pins were jumped, and it may only be for pre '96.

Yeah thats pre-OBD.

I used to do it on the Monte.

Sounds like it's time to hit the Autozone.

darthroush · Post by **darthroush** » Sun Nov 21, 2010 2:25 am

Some cars that have digital odometers can show the codes. Have you searched the internet for a how-to of sorts, providing it has a digital odometer?

If it isn't a digital one, you need a reader.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Sun Nov 21, 2010 8:07 am

darthroush wrote:Some cars that have digital odometers can show the codes. Have you searched the internet for a how-to of sorts, providing it has a digital odometer?

If it isn't a digital one, you need a reader.

It is a digital odometer, that's why I figured it would be able to. Even if it wasn't digital, I was thinking that maybe it would do something similar to 1gn's.

We're going to hit up Autozone tomorrow. Thanks for the help guys!

Oh, and I got another question on a separate vehicle. I don't have much experience with diagnosing cars and stuff, so I don't know if there's something else to look at when a problem arises, but what would typically cause a "catalytic converter" code? My mother-in-law's Mitsubishi Eclipse [Spyder] is throwing a code... trying to get her to get the code so I can look into it further for her, but whatever shop she took it to convinced her to replace the catalytic converter and [of course] it didn't fix the problem. Just wondering what your guys' thoughts are on that.

Thanks again!

BlackRoseRacing · Post by **BlackRoseRacing** » Sun Nov 21, 2010 8:42 am

cat codes are caused by either a cat going bad or the downstream O2 sensor is failing. Depending on which code you had would help determine the issue. But if you already changed the car and the code came back, the cat was not the problem the downstream O2 sensor is the problem.

2005.Neon.SXT · Post by **2005.Neon.SXT** » Mon Nov 22, 2010 8:36 pm

BlackRoseRacing wrote:cat codes are caused by either a cat going bad or the downstream O2 sensor is failing. Depending on which code you had would help determine the issue. But if you already changed the car and the code came back, the cat was not the problem the downstream O2 sensor is the problem.

Forgot to check back on this thread. Been busy lately so I haven't had the chance to get that code, but I'll let her know. I appreciate the help.

Post by **occasional demons** » Mon Nov 22, 2010 10:54 pm

If it still has the same code after replacing the cat, the shop should be eating that cost. This is why you ask for your old parts before service.
I would hand it back to them, and tell them to reinstall it. But that's why they like it when females bring their car in. Most will not argue with them.

P0420 Catalyst System Low Efficiency
P0422 Catalyst System Low Efficiency Bank 1

This would mean the downstream o2 is reading too close to the upstream o2. It is the same code that you get doing a cat delete. Basically there is not enough change in o2 level going in, and coming out.

P0421 Warm Up Catalyst Efficiency Below Threshold (Bank 1)
Not 100% on this, but may mean the cat is not lighting off fast enough. May not even apply.

All the codes are universal between manufacturers, except for a few that may be specific to that brand.

Haganracing · Post by **Haganracing** » Mon Nov 22, 2010 11:20 pm

sidepipe87 wrote:
JeffM wrote:Neons are the only car I know of that actually shows the code.
Chryslers. Not just neons.

+1

My dad's Dakota, jeep, and minivan did the key trick too.