Illumination of the Check Engine Light can be caused by a loose or worn gas cap.Google+
Car Problem Reports
Chevrolet Colorado Check Engine Light Due to Gas Cap Issue
Chevrolet Colorado Problem
Average Mileage: 77,576 mi (1,335 mi - 129,500 mi)
Visitor, 2004 Chevrolet Colorado, 77,950 mi
The check engine light on my 2005 Chevy Colorado kept coming on. I took it to a garage and had them hook it up to their computer. they told me it was due to my gas cap.
Visitor, 2004 Chevrolet Colorado, 85,500 mi
This has happened and i replaced the gas cap twice! Yes, the CEL went off BUT NOW back on, had the shop hook it up and test. It is caused by a BAD PCM! The comp. bad causing all kinds of electrical issues such as the rear light out, blinkers would work then randomly not. The heater and ac work n not work when ever it felt like it, and the CEL and gas cap notice on dash. The shop stated Colorado are known for electrical issues and it seems as if everyone is working around the issue and never actualy get the problem and it re-occurs after time and it is the PCM causing mis reads and missfires on codes and all electrical issues.
Visitor, 2004 Chevrolet Colorado, 106,000 mi
fuel cap light on, and check engine light on. Replaced gas cap twice, still does it.ANNOYING!!!!
The fan for the heat a/c quiets working at regular intervals. The resistor pack has been replaced and the wiring harness has been repaired, but the problem is still there.
Visitor, 2004 Chevrolet Colorado, 1,335 mi
Check gas cap message, failed inspection twice
Visitor, 2004 Chevrolet Colorado, 83,500 mi
check engine light comes on. problem could not be found. persisted for approximately 3 years. judy took it in for another look and they, the dealer, found that there is a hole in the gas tank. i was told that i needed to change the gas tank. Prior to this, i has the gas cap replaced 4 times, the gas line to gas tank replaced and everything else up to the tank replaced just last year. from the gas cap to the gas tank is all new, less than two years old.
Visitor, 2005 Chevrolet Colorado, 67,000 mi
check engine light on. replaced cap and went off for a few months. back on again.
Visitor, 2006 Chevrolet Colorado, 129,500 mi
THE GAS CAP DID NOT SOLVE THE PROBLEM .
Visitor, 2004 Chevrolet Colorado, 114,000 mi
cant seem to stop the light from coming on after three gas caps newly replaced. anyone have a fix
Check engine light came on, replaced gas cap, fixed problem.