Engine Light on after Getting Gas

98 Tacoma 3.4L 6 Cil. Extra Cab. Just had my timing belt done few weeks ago and replace water pump thermostat etc.. No issues. Everything normal. Truck still driving beautifully and normal.

Yesterday got gas. put 3/4 tank in then Check Engine comes on. Check Gas cap and seems tight and normal but girlfriend got the gas and put it on so just checked to make sure. Remove and re tighten and check engine light still on. Any ideas? It says in the manual if the gas cap is loose it can come on. I do not have a code reader but can go and get it done if needed I suppose. What are the most obvious things I can check? THX guys.

 

So you're on the right track. It's going to be one of 4 items: Gas cap, filler neck, charcoal cannister, or fuel tank check valve. I'd start with a new gas cap, since it's much cheaper and easier than the other 3 items, then go from there.

I had the same problem, and couldn't add more than a couple gallons of gas at a time last year. Ended up replacing both the charcoal cannister (very pricey), and fuel tank check valve. I believe it was the charcoal cannister that was the problem, but cannot confirm, as I replaced both at the same time.

 

Give it a day or 2, if it is the fuel cap it might be self correcting after a few cold starts.

 

I will wait a few days. I do notice slight hiss of air when I open it to get gas. Is this normal? I have read there is a valve. or is it doing it's job not letting air out. I I could replace it to try fixing the error. What is the goto good locking gas cap? Anyone got a link?

 

That hiss is normal it means that the system is holding pressure and vacuum, it goes through both during normal opperation.

 

Mine was making a hiss too, until I replaced charcoal cannister and check vakve. That could mean the fuel tank check valve (see part # below in screenshot).

Also this thread has some useful information about this problem:
https://www.tacomaworld.com/threads/cant-fill-up-with-gas-nozzle-clicks-too-soon.829414/page-2

 

Anyone know a good licking cap to try? See some on Amazon: thx

 

I wouldn't. I've heard mostly bad things about aftermarket gas caps causing the exact issue you're trying to solve...I would just get a new Toyota one or find a good used one. If you want to lock it I would look for a locking gas door instead.

 

anyone know will the check engine light go off after solved or is there need a reset routine on my 98 to reset it? thx

 

Once the ECU runs an emissions cycle the light will go off on its own if it's able to complete the cycle without detecting any issues. So it likely won't happen right away. But you can force it to start a new cycle by disconnecting the battery or plugging a scan tool in and resetting the code. That resets the emissions cycle and turns the engine light off. If the issue is fixed, it will stay off. If it persists, the code and light will come back.

 

I was filling up and it overflowed (pump didn't auto shut off) causing the CEL to come in as soon as i started it up. Got a scanner a few days later (forget the code) but after searching the code the most likely reason was the cap in most cases, which was odd since the cap wasn't part of the problem that caused the CEL. Instead of replacing anything, I just cleared the code. Haven't had issues in a few months now and when fueling up the auto shut off work. I blame it on that specific pump I was at and because it overflowed it through the CEL.

 

I have read you can hold the odometer button down while starting the truck to clear the CE light. Anyone know if this is the case on the 98 Tacoma?

 

You need an OBD2 scanner to read and erase codes. You can get one on Amazon for cheap. Like $40.

 

that just resets the trip odometer. You need to use a scan tool or disconnect the battery. Both will reset the emissions cycles with clears the code.

 

Ok will do the battery. Thx.

 

Just pull the code or disconnect the battery. No point in shotgunning parts

 

I don't think it's true on anything.

Just disconnect the negative battery cable for a couple minutes and that will clear it.

The code will come back pretty quick if the issue wasn't resolved. So. If resetting the gas cap was the answer, you'll be good. If it wasn't, the light will return and you'll want to get a reading.

 

The best thing you can do for your wallet is to scan the codes first and at least see what they are. Don't buy anything yet

 

would this work?

$18 OBD2 Scanner Ease Setup Plug-Play: Clear Reset Engine Error Code Professional Code Reader Diagnostic Scan Tools with Freeze Frame/I/M Readiness for All Cars Since 1996 & Newer - LK11

https://www.amazon.ca/OBD2-Scanner-...ource=1#aw-udpv3-customer-reviews_feature_div

 

Once I get the codes how
do I decipher what it means or what it is saying?