'01 Grand Cherokee CEL came on last night. Dummy gauges are fine, other than CEL and runs fine. possibly a slight miss. Thinking maybe fuel cap because it came on within 15 km of fueling up. Is there a way to pull a code without a reader? I know OBD you can pull a code using a voltmeter, I can on my '91 laser anyway. My search came up with using a reader only. Just wondering if anyone knows different? Thanks