Coworker has '04 Chevy Blazer with recurring "check engine light' problem at only 33,000 miles.?

Question

2004 Blazer has recurring "check engine light" problem with only 33,000 miles on it. Each time it happens the dealer sells him a new gas cap and resets the light. He's already bought 4 new gas caps, and now the light is on AGAIN. Can anybody tell us what the problem really is, and how to fix it? Thank you very much!

Answer 1

The most frequent cause of a check engine lamp on that vehicle is DTC P0442, Evap Small Leak Detected. This normally leads morons at dealerships (or any shop for that matter), to replace the fuel cap, because the fuel tank cannot achieve the vacuum level needed to run a certain emissions test that the computer performs under certain conditions. The true, only way to test it is using the Tech2 scan tool to perform the Evap system seal function, then use a kentmoore tool called an "Evap tester" to do both a flow test, and a smoke test which reveals the location of a small leak. The leak is usually not fuel, it's a vapor leak 99.9% of the time. The problem is the jerk at the dealer he is taking it to, doesn't know what he's doing. I work for GM in a Chevy dealer and fix these types of issues all the time. As much as you and your friend probably won't want to hear this, you will need to take it to a [different] dealership and explain the history of the problem so far, to give them a good starting point. The vehicle is still under the 3/36 warranty, so there is no cost to him, except his frustrations... Things like this give dealerships a bad name, but as I have worked in both Dealers, and Independent shops, I can tell you that from a diagnostic and technological standpoint, the dealer certainly has the advantage with the lastest tech., and information from engineering. Good luck with the "idiot light."

Answer 2

with out getting under the hood i cant tell u the exact problem but i can give u some things to look at.......one some of the newer chevys engine light come on when its time for an oil change or other fluids are low,or it could be a sensor going out and since it hasn't went out completely there computers are not detecting it. it could also mean he needs a tune up and dont forget to check fuel filter it has been 33,000 miles

Answer 3

wow...you'd think after the second gas cap he'd get the clue that the dealer's a dumbass...it has nothing to do w/ the gascap...it's whether he's screwing it down all the way or not. also, the dealer should be able to plug a diagnostic connector in and see exactly what the problem is.

Answer 4

If it's coming back as a gas cap, his gas tank is not building pressure. #1 He needs to go to another Dealership. #2 when he gets to the Dealership he needs to have them do a smoke test on all his fuel lines to find a leak.

Answer 5

GO TO A DIAGNOSE SPECIALIST IN AUTO ELECTRONICS(GO TO A VERY WELL KNOW MECHANIC IN YOUR AREA) HE'LL PUT IN THE COMPUTER READER HE WILL TELL WHATS WRONG WITH IT. NEVER, NEVER, NEVER GO TO THE DEALER TO GET SOMETHING LIKE THAT FIXED. FROM WHAT U TELL ME I THINK THERE MIGHT BE SOMETHING WRONG WITH UR FUEL SYSTEM.