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My check engine light came on today I stopped by Autozone for the free check engine light test. He said it was the gas cap. I bought the $10.00 cap but have not put it on. I'm just wandering if this could really happen or did I just waste $10.00. The manual says it is some exhaust problem. The Autozone guy also said the light would go off in just a few day or I could just disconnect a side of the battery and it would go off. What do you think?

Posted by Anonymous on


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Hello anonymous...

Pretty vague question...
will get you a pretty vague answer.

in FACT... it was a GAS CAP...
Wasted money... NOT at all.

It could be... POOR surface seal or simply loose...
(part of your emission control system: sealed fuel system)

((depending of course on YOUR year, make & model))...

Most the sensors are made to "COMPLAIN"
if the GAS cap is left off... or loose (not properly sealed).

it should RIGHT ITSELF if it LATER makes a good seal...

AS to wasted MONEY... DEPENDS entirely on the
condition of the OLD CAP... (spare parts)

& the competence of the AUTOZONE READER.

Really... BUT even IF THE ALARM persists...
>> NO (in my opinion)... That was NOT a waste
of your money (you are now that much smarter).

Disconnecting the BATTERY is a bad idea...
Get the codes reviewed by a COMPETENT
technician... or present ALL the codes & vehicular
nomenclature (make, model, year, engine... (etc.)) here...

We can help ... FREE.

Carnac the Magnificent

Posted on Jun 27, 2017

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I think that the autozone guy should learn how to read a scanner and tell you the codes so that you can verify the problem
the only problem requiring a gas cap will show up as an EVAP problem and the cap shows as a large air leak which means that the cap was not properly fitted or tightened
he could have reset the light with the scanner
removing a battery terminal looses radio codes and will affect the ECM program so should be only considered after due consultation

Posted on Jun 27, 2017


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SOURCE: 2007 gas cap light comes on then the ckeck engine

maybe they got a malfunctioning sensor it happens go back

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SOURCE: 06 chevy impala v6 3.9 liter engine. Check engine

there is a large evaporative leak. keep away form ottozoo, they dont have the brain power to actually diagnose a light bulb., their job is to sell parts., if they sell you the wrong parts tough.Take it to a qualified repair shop that does a lot of GM work or the dealer.

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SOURCE: 2006 Saturn Relay Check Engine Light

PO455 is a large evaporative fuel leak. A bad fuel cap is ONE of the things that COULD be the problem. Fuel system cleaning only lightened your wallet. Reading your post is confusing. Did all this start AFTER the Valvoline Wallet Flushing? If so , they left something loose or disconnected. I would find a qualified repair shop to fix the problem, and if it has anything to do with what Valvoline did, make them pay the bill.

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SOURCE: service engine soon light came on. AutoZone read

Sometimes you have to wait a week for the light to go off, the computer has to go through several start/run/stop cycles.

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SOURCE: my 2005 Jeep Liberty v6

Give the computer a day or two to recognize the new gas cap and turn off the light. If it doesn't go off, your best bet is to visit a parts store and have them scan the computer for you to determine the cause of the light. Auto Zone and several other parts stores will run the scan at no cost.

Posted on Oct 07, 2010

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