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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.
The Check Engine light came on in my V-8 4x4 Tundra. The guy at the dealership suggested maybe the gas cap was not tight. I looked at it, and it was tight. Check Engine light is still on. Looked at the air filter, which is kind of dirty.... could it be that? Any other suggestions for what to look for? Thanks.
Kirby
gas cap? O well. Disconnect the battery for a min or two. If it dosent go away then there really is somthing wrong. Check to make sure your o2 sensor is in tight and is working proporly. Air filters are cheap so you can replace that or blow it out with shop air or suck it out with a shop vac. Is the oil at the correct level?
If you have an AutoZone nearby, take it there and they will do a free OBDII diagnostic check which will tell you exactly what is causing the check engine light.
If a loose gas cap is not the cause, then the next most likely cause is an oxygen sensor heater circuit failure on one of the front O2 sensors.
Have you dropped your gas cap lately? Same thing happened on my Avalon. I dropped the cap. Looked fine but apparently it did something to it because a short while later the light came on.
Did everything...tightened it, disconnected the battery, etc... Finally took it to the dealer and they replaced the cap. Fine ever since.
Thanks very much to all of you for your suggestions. I changed the air filter, then disconnected and reconnected the battery. The light went out, and "so far, so good".....
Kirby
Those diagnostic checks will tell you what is causing the light. However not the root cause. Check this one out. My engine went out,not compression on cyl. 4 and it starteed with a knockin noise and a check engine light a few min. later. They tear it down and it nood a new short block. They replace the short block and I pick up the truck. Drive it a few blocks, no power and wont go over 60. Running way way bad and loud and no power. The truck was no way ready. I wouldnt pay $100 for a title on a car that ran like this truck. The shop take it out again and a few min. later they drive it back in and hook it up. The diagnostic check tells them its burning lean. No when I put my K&N on the oil from the filter fouled the mass air flow sensor wired causing a lean burn and a check engine light to pop on. now they replaced a whole short block her and they point to the K&N and a fouled sensor. They rule that one out and disconnect the manifold and check some things. Well we know how these V8 manifold hold up. Ones warped and they crack the other. So a new block and its not ready and now new manifolds and a whole weekend stuck 500 miles from home. New manifold by night and still no power. Now after all this they discover that after the block they set the timing on the wrong mark on the cam. Readjust the timing and all of a sudden we have power. So what happened here was a bad timing setting causing a lean burn. Along will a V8 with no and I mean no power. And if the diagnostic check had pionterd to the timing we would still have the original warped manifolds on the truck and instead of holding up over the weekend I could have driven home Friday afternoon. what
i want to know is what all the computer on board will in fact tell you and to see the breakdown of there diagnostic at toyota.
Originally posted by mikeinaustin Haynes sells a manual that lists (and very briefly describes) all the ODB-II error codes along with maker specific (for example, toyota) extensions.
Well, the light came back on and although I appreciate the last suggestion (LOL), I can't get used to it. I took it to AutoZone and their computer said both oxygen sensor heater circuits are bad. $69 each but it ain't payday yet, so I'm going to try to clean them tomorrow. Anyone ever tried cleaning the O2 sensors?
Kirby
Kirbybus,
There's two circuits for those sensors, your heater circuit is bad so i don't think cleaning them will help. just south of you PM me if you need a hand getting them replaced.
I had mine on for one day, but that was my fault. When I replaced the air filter, I neglected to re-connect the electrical connecter for the intake sensor. Reconnected and the ck engine light stayed on for my drive into work. Later in the afternoon when re-started, the light was out. Smart truck, that Tundra.
Check Engine Light
Linear Mode
