I have a '96, I just replaced my whole exhaust.
I also changed the Oxygen Sensor.

Can someone tell me if I need to go to a shop or
just disconnect the battery for a few minutes to reset
the Check Engine Light?

Thanks ahead for any info.

 

unhook battery

 

You should get the code Checked. Auto zone does it for free. Unhooking the battery doesn't fix any problems

 

Take it to a auto parts store to run a code scanner on it. If you want to clear codes you can do it by resetting the comp.
1. unhook battery (5-10min)
2. touch the two cables together, then reattache to the battery
3. turn ignition to the on posistion (do not start)
4. Turn on lights (count to ten)
5. turn off lights, turn off ignition
6. start your jeep and the computer is now reset (it will use the next 50 starts to relearn base values for your emissions.


note: This should be right, but I am old and at work so no yelling at the old guy if I mis-remembered

 

DONT LISTEN TO HIM. do not touch the cables together. just disconnect them and wait like 15 mins. touching battery terminals together is the worst thing. what o2 senson did u replace. i recently went thru this myself

 

I didn't mean the terminals, I ment touching the cables together (after you unhook them from the battery) to release any residual charge, I have done this many times. Sorry if I mis-spoke but this is what I do and have had no issues.

 

Touching the cable ends together drains all capacitors down, whereas just leaving them unhooked, even overnight sometimes won't. Just an extra "precaustion" to make sure the thing is completely drained. BTW do not do this to most late model 01 up GM stuff.....

 

Another way to go here.....
--------------------------------


This procedure is for OBDII Jeeps.

This six step procedure will erase the “Adaptive Memory” stored inside the PCM and allow a new “Adaptive Memory” to be developed. After performing this procedure the PCM will re-learn and store into Adaptive Memory your engines performance characteristics.

Perform these steps exactly as they are written, in the order they are written. This will cause the adaptive memory in the PCM to be erased and cause the PCM to go into Fast Learn Mode adaptive mode.

1. Disconnect the POSITIVE battery Terminal and touch it to ground for 30 seconds. (This is to discharge the PCM capacitors, which maintain the Adaptive Memory.
2. Reconnect the Battery Cable
3. Turn Ignition Switch to the “On” position but DO NOT start the engine
4. Turn Headlight “On”
5. Turn Headlights “Off”
6. Turn Ignition Key “Off”


The PCM Adaptive memory has now been flashed, or erased from the PCM.
When you start the engine it will be running off a set of pre-programmed values that come with the PCM from the factory. When you get the engine up to operating temperature the PCM will start to collect data for the “Adaptive Memory”. The PCM will collect data for Adaptive Memory for the first 50 warm-up Cycles.

 

yes i misunderstood you i didnt know thats what you meant hahah my bad. and im trying to see if this guy replaced just his downstream o2 because i did the same thing and it turned out my front upstream o2 sensor was shot and causing my check engine light to stay on. id replace both but get it scanned first as a precaution https://www.cherokeeforum.com/images/icons/icon14.gif

 

I replaced the one closest to the engine. I did disconnect the one by the Cat. Converter, but I did not replace it.

What they mean by touching battery cables together... touch the cable ends together, right?

Thanks for all the input.

 

After you have disconneted the cables from the battery (both cablels must be un-hooked from the battery) you touch the positive cable (red) to the negetive cable (black). This is done to discharge any residual charge left in the syestem.

 

get the code pulled my guess is the downstream o2 sensor in the cat is bad

 

There is no real need to disconnect battery cables and dump adaptive memory. You could hook up a scan tool and clear the code or you can just drive the vehicle. After a number of drive cycles with the problem fixed, the check engine light will go out on it's own. There will be a stored code, but it shouldn't affect the way the Jeep runs.