Waynerd

This works for xj Cherokee. Yours is a kl. try here. https://www.cherokeeforum.com/f87/

BobF

I would start a new thread and fill out your vehicle information in your profile.

AtlBo

Signed up just to say thanks for this information. I know it's hard not to hate, but this fix saved me alot of hassles, so please not too much mockery. Had been running 95 Cherokee with the tire pressures very low without realizing it (in the 20s), and I wondered why the transmission was behaving so badly. Back up to 35 pounds and a reset and this Jeep is back in the game. Thanks again. Glad I hadn't yet gone through with the $1600 transmission rebuild like I had been planning. Been so busy I hadn't given the proper time to the old Jeep. blush:

BTW, had a new battery put in about 4 months ago, and I think the ECU reset then, just as the Jeep was really getting bad. It learned all my bad driving tendencies during the time following the installation. This reset means a chance to start all over thank goodness. Can't hardly believe the change.

Charles Umholtz

resetting the ecu with the brake did not work and is bulls!@t!
The proper way is the 1st method, but I would love to speak with an engineer and wonder why you have to turn the headlights on and off?

Ralph77

I do the same procedure, with the headlights, every time I make a major change. I wondered about that too. I was told: "Turning on headlights with battery disconnected will drain any remaining charge left in systems,components, capacitors."

DFlintstone

With not much more than a basic understanding of the system: When the puter has no power at all it resets to it's default settings, like the day it was installed.



Puter has capacitors that can hold a charge and keep "awake" for a while. Effectively grounding the Jeep side positive with the terminal off by turning on the headlights does no harm.



Might be for us just disconnecting the battery overnight will do whatever that can do as far as a reset, lights or not, probably doesn't matter as there are other drains.

BobF

No. 84-01 . And for others: The computer on these old models is basic at best. When computer resets, it has 'default settings' to help get the car going. When resetted for me, the gas mileage goes down as the computer 'learns' the proper settings for my jeep. After quite a few stop starts (hot cold, you can't just sit in a parking lot and turn it off and on), my gas mileag does get back to normal, about 13mpg (USA). On a side note, I've done all the tips here on this forum (which is a great place for info), and that 13mpg average is as good as I can get. The max I ever got was 19mpg on a flat highway run down I-5 from Sacramento to Paso Robles CA.

Tbone289

I agree with that statement. But, in the sequence posted in the first post of the thread, and seemingly everywhere else on the 'net, the headlights are turned on and off after the battery has been reconnected.

vadim

+1 on the reset procedure. I replaced the IAC, cleaned the throttle body, and after that the engine would idle at 2,000 rpm. Did the reset, and it's back to ~750.

al123

[QUOTE=DaRock;521849]Home » Quadratec Knowledge Center »

Jeep Electronic Control Unit Reset

When installing new power or performance accessories how does the computer for the Jeep know that it has a new accessory? Most of the time the computer does not. The computer would need to be reset to take full potential of the performance accessories you have added.

The Electronic Control Module, or ECU as its commonly called, stores the information for your vehicle and your driving habits in its memory. The memory is maintaned by a series of capacitors that hold a charge and maintain power for the ECU when the vehicle is turned off. The following procedure will allow you to reset the memory and allow the computer to 're-learn' how to drive by adjusting to the drivers habits and the vehicles modifications.


1. Disconnect the battery by removing the positive battery cable. Remember, the positive battery cable.

2. Ground the positive cable to the negative cable for 30 seconds to erase the electric charge in the capacitors.

3. Reconnect the positive cable to the battery.

4. Turn the key to on but do not start.

5. Turn the headlights on.

6. Turn the headlights off.

7. Turn the key off.


The ECU has now been reset to its factory settings. For the next 50 warm-up periods the ECU will re-learn the engine and driving habits for your driving conditions and the newly installed parts.[/QUOTE

You say during the 50 warm up start up do you mean like driving it too

al123

Do I do this while driving during the 50 warm ups? It still idle rough at start up btw placed all six injectors and resetted the ecu.

Jrack

I have a 2001 Jeep Grand Cherokee.
I tried the 1st method and it ran for a few seconds and now it want start. It also beeps twice at the end when I try to start it. No codes

DFlintstone

Hi Jrack. You might have better luck in the Grand Cherokee section......

Jrack

Okay, thanks!

jordan96xj

Put your key in the driver side door and rotate it back and forth fully 3 times. It will reset the security system and allow the startup. This is common after killing/disconnecting the battery on the factory security system.