Need an OBDII reader - any advice?

[DaveD912]

This morning the CEL on my '99 sport stayed on. I called around and can't find anyone that'll read it for free . The Jeep is running fine, so I thought I'd get a reader and fix this myself. I have a laptop, so I could either get software and an adapter for the laptop or a handheld reader. Any suggestions?

Some background on the CEL... I normally drive a short, low speed, 7 mile commute, but yesterday (and the rest of this week) I'm going about 30 miles on the Turnpike at about 70mph. The CEL light wasn't on yesterday, but stayed on this morning and the exhaust smelled funny on startup. I can't decribe the smell though, it's like nothing I've smelled before. I've tried all the 'key tricks' and none work for me.

[langer1]

If you have a laptop I would do it that way but Autozone will read the codes.

[UNCC_99XJ]

Autozone will read them for free.

As far as purchasing a scanner of your own, they're pretty cheap now....I say that in comparison to what they used to cost.

Make sure you get a scanner that has the ability to read and CLEAR codes. There are some out there that just read them, and do not clear them (the scanner autozone uses for example just reads them).

It might be worth your while to spend a bit more and get one that can do some live readings (like TPS voltage, o2 sensor readings, etc). I have a scanner that just reads and clears that was given to me by my dad, but he also has another one that i've used before that does some readings like those i mentioned. It came in real handy when I was trying to track down a failing TPS in december.

Search around on the net some. I believe Harbor Freight even sells OBDII scanners and they're priced good.

[DaveD912]

I found an Autozone, so that's how I'll get it checked tonight - thanks. I may still get a little reader though. For those interested, Amazon has the cheaper Actron for $55.

[UNCC_99XJ]

Originally Posted by DaveD912

I found an Autozone, so that's how I'll get it checked tonight - thanks. I may still get a little reader though. For those interested, Amazon has the cheaper Actron for $55.

It wouldn't hurt. In fact, I find its quite nice having one of my own. I've actually gotten good at getting it plugged into the port while i'm driving down the road...lol

Plus, when all my buddy's have theirs come on and start freaking out like it's going to blow up, I can pull the codes off of theirs.

[Rick Anderson]

Have you tried the Key On-Off-On-Off-On method? On Chrysler Vehicles this will cause the Engine Computer to blink out its fault codes with the CEL. 2 digits codes. I'm not positive this feature is on all late model Jeeps, but '99 Jeep was pretty well integrated with Chrysler Technology, I'd be surprised if it didn't work.

The codes from the CEL are 2 digit, i.e. there will be a pause between each number, arrange the numbers in pairs as they are blinked out and that will be your codes. Do a google search for the codes for your vehicle and you can tell.

One note, the blinked out 2 digit codes are less extensive than the 4 digit scanner read codes. Usually the 2 digit code may cover several 4 digit codes. Sometimes the CEL blinked 2 digit code will be all you need to correct the problem, sometimes it won't be enough info and you need to get the 4 digit codes read with a scanner or do some trouble shooting to narrow it down.

Good Example, a code 21 (from a blinking CEL) for O2 sensor, covers 8 different 4 digit codes read from a scanner. Half of those codes or for the Upstream O2 sensor and the other half are for the downstream O2 sensor. So the 2 digit CEL code only tells you one of the 2 O2 sensors have a problem, and not which one of the 2 or what specifically the problem is.

[Matthew Currie]

Originally Posted by Rick Anderson

Have you tried the Key On-Off-On-Off-On method? On Chrysler Vehicles this will cause the Engine Computer to blink out its fault codes with the CEL. 2 digits codes. I'm not positive this feature is on all late model Jeeps, but '99 Jeep was pretty well integrated with Chrysler Technology, I'd be surprised if it didn't work.

The codes from the CEL are 2 digit, i.e. there will be a pause between each number, arrange the numbers in pairs as they are blinked out and that will be your codes. Do a google search for the codes for your vehicle and you can tell.

One note, the blinked out 2 digit codes are less extensive than the 4 digit scanner read codes. Usually the 2 digit code may cover several 4 digit codes. Sometimes the CEL blinked 2 digit code will be all you need to correct the problem, sometimes it won't be enough info and you need to get the 4 digit codes read with a scanner or do some trouble shooting to narrow it down.

Good Example, a code 21 (from a blinking CEL) for O2 sensor, covers 8 different 4 digit codes read from a scanner. Half of those codes or for the Upstream O2 sensor and the other half are for the downstream O2 sensor. So the 2 digit CEL code only tells you one of the 2 O2 sensors have a problem, and not which one of the 2 or what specifically the problem is.

The 99 does not blink out 2-digit codes, and requires OBDII. Check out Sears for their prices on various Actron readers. Even if Autozone reads them free, it can be pretty handy to have your own, and to be able to cancel codes with it too.

My wife's volvo throws a coolant temp code almost every time she runs it in below-zero weather. The reader has paid for itself by now, just in time and aggravation saved.

[UNCC_99XJ]

Originally Posted by Matthew Currie

The reader has paid for itself by now, just in time and aggravation saved.

X2. Been chasing an o2 Sensor code on mine for a year...saved a lot of aggrivation with mine.