Codes, Got them... But????

[Big Willy]

Just wondering if I am doing this right. I have the breakdown of the codes but I can't get them to work on the 94 XJ. I know that you have to turn the ignition off to on 3 times but is there something else that I should be doing. ie: turn so fast during a certain amount of time, I am not using enough/too many turns of the key? Any help or experiences doing this will help.

[The Garagemahal]

1 Start your jeep
2 slowly rev engine to 2000 rpm
3 slowly de rev
4 cycle gears
5 cycle air (if equiped)
6 turn off engine
7 turn key on/ off 3 times
8 count check engine light blinks

there should be a long pause between # 's, short pauses mean same # longer pauses are next #'s
all #'s are 2 digit ( I think)

[Enos]

Or, just do the following:

Starting from the off position, turn the key on (not start), off, on, off, on withn a couple of seconds. The codes will flash the check engine light, you have to watch close and it might take a couple of times to figure out the different pauses between the long and short pauses. The long pauses seperate the digits and it should end with 55 flash-flash-flash-flash-flash-pause-flash-flash-flash-flash-flash.

What is the purpose of the engine reving and other stuff?

[The Garagemahal]

When I was looking to retreive the codes for my MJ I found out how to in my xj/mj haynes manual . From what I remember it was to make sure of gas and oxygen levels and to check o2 sensers and idle . The gear cycles are to ensure that they are working

[Enos]

Cool.

[Big Willy]

Man I still can't get it to work? Oh well, I am heading in to see Andre in the morning so I'll get him to show me how to do it. I have owned 3 XJ's and I still can't figure this out, drives me crazy.

[CharlieXJ]

do you leve the key in the on position after on, off, on, off ect.?

[HardKorTJ]

yea i hate doing the key thing and counting them dam flashes, i bought a cheap coad reader when i worked at Crappy tire for 90xj

[Big Willy]

hardkorxj said:

yea i hate doing the key thing and counting them dam flashes, i bought a cheap coad reader when i worked at Crappy tire for 90xj

Really? What kind is it and how much does it cost? Would definetly be better than attempting this key thing. Like I said I have owned 3 XJ's now and never got this to work on any of them.

[justajeep]

It only works on 91 and up XJ's, so if you've had an older one that you tried it on, no wonder it didn't work! Not sure why you are having trouble, I've never had any trouble getting any Chrysler vehicle to do it.

[HardKorTJ]

they usaly have them in stock, wal mart have them too, i had to order mine in, cuse crappy tire only had the for and gm ones, i had it for my 90 and i havent tried it for my 93 but i dont think it will work. i cant remember how much it was, i have had it for a few years. i'll have to find it and read to see if it works on the 91 + xj's

[Big Willy]

jstasn said:

It only works on 91 and up XJ's, so if you've had an older one that you tried it on, no wonder it didn't work! Not sure why you are having trouble, I've never had any trouble getting any Chrysler vehicle to do it.

My first XJ was an 88 so that would explain that one. My other 2 are the 92 & 94 and it has never worked on these for me. I even tried Scott's method above today and still no joy. But like I said I'll get Andre to show me tomorrow when he's looking at my brakes.

hardkorxj said:

they usaly have them in stock, wal mart have them too, i had to order mine in, cuse crappy tire only had the for and gm ones, i had it for my 90 and i havent tried it for my 93 but i dont think it will work. i cant remember how much it was, i have had it for a few years. i'll have to find it and read to see if it works on the 91 + xj's

Thanks for the info. I'll check it out the next time I'm in Crappy Tire. What exactly are the readers called? That way I won't confuse the teenage partimer they will have at the counter.

[Big Willy]

Okay now I feel stupid. I was a bit impatient all these times because I was expecting the light to start flashing right away instead of a few seconds later. Now I got my codes.
One was 12 no biggie, the second though troubles me. It was 41 - Fault in the charging system or no field current. Anyone know about this one? Funny thing is though last night I tried it again (just so I would remember how and not ask this again, lol) and now it doesn't show up. Any thoughts as to what could be a source for the code or as to why it would just not show up anymore?

[The Garagemahal]

I think that once you check your codes you clear them until the problem acts up again

[Enos]

Some codes come and go and some are only reset by unhooking the battery. I had an intermittent O2 sensor code for about two years on and off.

As for what code 41 means, no idea, but it sounds like something in the charging system. It may be something that is on its way out and is only tripping a code sometimes.

I'm pretty sure checking the codes will not clear them.