local discount parts stores will sometimes scan for free and tell you the code, but don't buy the parts they think it is, they don't know what they're doing.
does the key cycle work on tj? i'm not sure, but if you cycle the key from off to on 3 times ending in on, the light will blink, count the blinks. first set of blinks will be seperated by a pause, first set is first digit second set is second digit. but this might only be pre obd2 cars. obd 2 are 3 to 4 digit codes, but maybe they have a 2 digit code for this that will translate. not sure.