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Engine & DrivetrainDiscussions about the engine and drivetrain of your vehicle.
This is a discussion thread titled "Check engine light", within the Engine & Drivetrain forum, part of the Technical & Vehicle Assistance Forums category.
my check engine light has once again come on. the last time it was because my gas cap was fully tight. the owners manual said it would go out after several trips and it did. this time after filling the tank it came on again. i retightened it and it is still on after several days. my truck is an '03 with 24k miles. could this be O2 sensors this time? i plan on taking it to the dealer since it is still under warranty if it doesn't go out soon. any other thoughts or experiences with this problem?
my check engine light has once again come on. the last time it was because my gas cap was fully tight. the owners manual said it would go out after several trips and it did. this time after filling the tank it came on again. i retightened it and it is still on after several days. my truck is an '03 with 24k miles. could this be O2 sensors this time? i plan on taking it to the dealer since it is still under warranty if it doesn't go out soon. any other thoughts or experiences with this problem?
thanks,
Rob
There are a large number of reasons why it is on - loose gas cap, O2 sensor, any failed system diagnostic . Many Autozone parts stores can read the computer and tell you the reason.
The Check Engine Light or Malfunction Indicator Lamp (MIL) comes on when the ignition switch is turned ON and the engine is not running. When the engine is started, the MIL should go off. If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system.
In addition to the MIL lighting up when a malfunction is detected, the applicable Diagnostic Trouble Codes (DTC) prescribed by SAE J2012 are recorded in the ECM memory. If the malfunction does not reoccur in 3 consecutive trips, the MIL goes off automatically but the DTCs remain recorded in the ECM memory.
__________________ ~Glenn~
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my check engine light has once again come on. the last time it was because my gas cap was fully tight. the owners manual said it would go out after several trips and it did. this time after filling the tank it came on again. i retightened it and it is still on after several days. my truck is an '03 with 24k miles. could this be O2 sensors this time? i plan on taking it to the dealer since it is still under warranty if it doesn't go out soon. any other thoughts or experiences with this problem?
thanks,
Rob
In addition to the causes that Glenn mentioned, a very common problem on '03s was a defect (pin hole) in the fuel filler tube. After you start the engine, the system pressurizes the emissions system and fuel filler tube...if it can't achieve pressurization within a certain time, it will turn on the CEL. Usually the culprit is a loose gas cap (as you've already experienced). However, quite a few '03s were produced with a defective fuel fill tube that eventually devloped a pin hole leak...which also prevents pressurization. This problem usually appears after refueling since refueling tends to stress the fill tube. A TSB was issued for this problem...if you are a paid member, look up the TSBs for your truck.
You can, as Glenn suggests, take it to Autozone for a free code read. If the trouble code matches the one for the fuel fill tube problem, you'll need to have the dealer replace the tube under the warranty.
__________________ Ray
Natural White '03 Access Cab V8 SR5 4X4 with TRD Off Road Suspension, Limited Slip Differential, and Towing Package
Towing & Performance Mods: JBA Headers, Gibson Muffler, 4.30 gears, Michelin LTX M/S Tires, Hellwig Anti-Roll bar, Prodigy Trailer Brake Controller, Autometer Z-Series Transmission Temperature Gauge, Magnefine Transmission Filter
Utility & Misc Mods: Genuine Toyota OEM Step (Nerf) bars, Peragon Tonneau Cover, TracRac Rack and Rail System, Muth Signal Mirrors, Pop&Lock tailgate lock, TruSpeed speedometer calibrator, "$20" RS-3200 Upgrade, Auto-Dimming mirror w/ Temp and Compass, Clear/Red/Clear Taillights with Silverstar Signal bulbs, 3M Clear Bra
Last Thursday the check engine light came on in my 05 Tundra and has not shut off since. I am taking the truck into the dealer on Saturday. I checked the usual things, gas cap, fluid levels, air filter etc. and everything seems normal. I wish Toyota had an onboard diagnostic check that the owner can perform just to rule out some of the simple causes.
Last Thursday the check engine light came on in my 05 Tundra and has not shut off since. I am taking the truck into the dealer on Saturday. I checked the usual things, gas cap, fluid levels, air filter etc. and everything seems normal. I wish Toyota had an onboard diagnostic check that the owner can perform just to rule out some of the simple causes.
You can read the diagnostics yourself with a OBDII scanner.
__________________ ~Glenn~
Forum Rules
Searching for an answer to your Tundra or other Toyota question? search HERE!
Got a question 'bout TS.com site policy? click HERE!
Ready to create a new thread? WATCH THIS VIDEO FIRST.
In addition to the causes that Glenn mentioned, a very common problem on '03s was a defect (pin hole) in the fuel filler tube. After you start the engine, the system pressurizes the emissions system and fuel filler tube...if it can't achieve pressurization within a certain time, it will turn on the CEL. Usually the culprit is a loose gas cap (as you've already experienced). However, quite a few '03s were produced with a defective fuel fill tube that eventually devloped a pin hole leak...which also prevents pressurization. This problem usually appears after refueling since refueling tends to stress the fill tube. A TSB was issued for this problem...if you are a paid member, look up the TSBs for your truck.
You can, as Glenn suggests, take it to Autozone for a free code read. If the trouble code matches the one for the fuel fill tube problem, you'll need to have the dealer replace the tube under the warranty.
I took my truck to the dealer today with a copy of the TSB in hand. i told them if the filler neck wasn't the problem, i wanted it changed anyway. my truck was within the VIN numbers effected. it turned out to be the filler neck causing the check engine light, and was replaced under warranty. thanks for the info. i can always count on people in here to come up with great info. thanks.
Rob
I took my truck to the dealer today with a copy of the TSB in hand. i told them if the filler neck wasn't the problem, i wanted it changed anyway. my truck was within the VIN numbers effected. it turned out to be the filler neck causing the check engine light, and was replaced under warranty. thanks for the info. i can always count on people in here to come up with great info. thanks.
Rob
There was a member in Ft Worth who had the same problem with his filler neck. Glad you got that all taken care of
There was a member in Ft Worth who had the same problem with his filler neck. Glad you got that all taken care of
Well the saga continues with my check engine light. it's been 10 days since they fixed the filler neck and the light came on the way home this morning. i tried the gas cap again, no help. after a few choice works and alot of shaking my head in disbelief, i drove it straight to the dealer. no appointment just dropped on in. after checking the filler neck installation and testing my fuel pressure and vacuum system they have narrowed it down to a vacuum switching valve that's not switching. from what i gathered from the service rep., this valve ports pressure to the gas tank to pressurize it and check for leaks. the the valve is supposed to swap to vacuum to remove the pressure in the tank. mine is not swapping to vacuum, it's just staying on the pressure side. they had to order the part so one more trip to the dealer tomorrow.
Well the saga continues with my check engine light. it's been 10 days since they fixed the filler neck and the light came on the way home this morning. i tried the gas cap again, no help. after a few choice works and alot of shaking my head in disbelief, i drove it straight to the dealer. no appointment just dropped on in. after checking the filler neck installation and testing my fuel pressure and vacuum system they have narrowed it down to a vacuum switching valve that's not switching. from what i gathered from the service rep., this valve ports pressure to the gas tank to pressurize it and check for leaks. the the valve is supposed to swap to vacuum to remove the pressure in the tank. mine is not swapping to vacuum, it's just staying on the pressure side. they had to order the part so one more trip to the dealer tomorrow.
Rob
My 2002 Sequoia did this. Had it to the Stealership 3 times to "clear" the code for me "not tightening my gas cap." After the third time and a possible call to the State Police, the Tech replaced the charcoal can vent valve on the driver's side valve cover. By some "magic," the gas tank now was brought under a slight vacuum when the cap is removed and no more MIL (lamp) for over 40K.
My check engine light just came on today. I recently got the oil changed, but all my levels are ok, no leaks under the truck or by the oil filter. I retightened the gas cap, but the light is still on. I've read everything on the sight about dealing with the "check engine light", so if it doesn't turn off in a couple days, I'm just gonna take it to the dealership.
My check engine light came on Sat. after I changed my oil at 36016 miles. I broughtit to the dealership today and they replaced the filler neck. I hope that takes care of that.
My dealer did it even though I'm just out of warranty!
Quote:
Originally Posted by fixin737s
I took my truck to the dealer today with a copy of the TSB in hand. i told them if the filler neck wasn't the problem, i wanted it changed anyway. my truck was within the VIN numbers effected. it turned out to be the filler neck causing the check engine light, and was replaced under warranty. thanks for the info. i can always count on people in here to come up with great info. thanks.
Rob
I went to the dealer w/the TSB (Thanks TS) and they replaced the fuel filler neck for free even though I have 37k on the truck. Now THAT is service!
Check engine light
Glad you got that all taken care of 
JOHN
My dealer did it even though I'm just out of warranty!