How do you check the diagnostic codes on this model vehicle? It's a 02 Cherokee Sport with the 4.0L and auto transmission. I assumed I could check it the same way as I do my 91 YJ 4.0L by running the engine to 2500 rpm, letting the rpm drop and turning the ignition off, then on, then off, and back on and waiting for the Check Engine light to flash out the number pairs, but it don't work that way.
Help appreciated. Scott
Bill,
I tried as you suggested, but the odometer does not change off of the milege reading. On the 4th on, all that is shown is the milege. I assume that the 1st "on" is engine start then off, on/off, on/off, on. I also tried an additional on/off/on, but no change.
Scott - you do this with the engine off, not running at all. It has the codes already stored up in the computer and all you are doing is invoking it to display them. I suspect Bill copied the stuff below from somewhere, but I remember only needing to do it 3 times, and at a regular cadence. Tomes
02 TJDo not start the engine just switch between the off and ignition on (but starter not engaged) as described at:
Retrieving codes: Turn the ignition key until the digital odometer displays, repeat three times in succession and then back to "On" (On/Off, On/Off, On/Off, On). At the fourth "On" the odometer will be replaced with codes. If no codes are present then "Done" will appear.
The explanation for the codes is also available at:
Bill, I think he is starting the engine each time.
The 2002 is OBD II compliant, go to the store and buy a diagnostic code reader, or use theirs for free. AutoZone will pull the codes for you, they simply plug the code reader into the data port on the bottom of the dashboard (near where you left leg rests while driving).
On your '91, there is no need to run the engine to 2500 RPM. Just turn the key on and off 5 times within 5 seconds, then leave it on and count the flashes.
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