Check engine light on a '98 Toyota T-100


I have a 1998 Toyota T-100, in February of 2006, i finally got it back from the shop in March of this year. $8000 to fix it. But since I’ve had it back, the check engine light seems to keep coming on. I’ve taken it to the toyota dealership about 4 times since. I will take it in and tell them, and the next day they’ll call me and tell me its done, well i will drive home (which is about 75 miles away) let it settle overnight then when i go to drive it to school the next day (which is another 30 miles) the check engine light comes back on. They first told me it was the battery, (my dad and i fixed it) and now they keep telling me it’s my gas cap, that the little computer thing they hook up to my truck tells them it is an evaporitive fuel leak. it used to be (before i wrecked it) that i could just turn the gas cap a few fimes and it would be fine, well oviously i would do the same thing when i got it back. after i told the dealership this, after the 3rd time to take it in, they told me to only let it click once because if i click it about 2 or 3, it would break the seal that it hs and that’s what keeps making my check engine light come back on. well for the last 2 months, everytime i fill it up i only let it click once. but yet it is still on. any advice?


Although it is quite common for an EVAP leak (small) to be caused by the fuel cap. There is however many associated parts and hoses attached to the system. I had a cavalier that kept turning on the check engine light because the o-ring on the fuel pump housing was bad.
There are two codes for this problem a SMALL leak and a LARGE leak. Do you know what code is being set?
What area of the truck was damaged? Possibly that could help in the diagnostic process.
~Michael (Dartman69)


the front passanger side of the truck ran into a tree doing about 50, and i dont know what type of leak it was, but im looking at the paperwork that they gave me and it says that they “removed and replaced the charcole canister and vsv valves and vacuum hoses and lines” and they also “performed a level 2 evap leak test and found no leaks” but yet they keep telling me that is what it is


here is a pic of the damage i did


here is a pic of the damage i did


here is a pic of the damage i did


Am I correct in my assumption that this problem existed before the wreck?
~Michael (Dartman69)


no, this didnt start until after i wrecked it, about 2 weeks after i got it back, before i wrecked it, it was fine i never had any problems with it


When the ECM runs the test on the EVAP system it is applying vacuum to the fuel tank with all valves closed then measuring the rate of vacuum decay. It can detect a leak in the system as small as .020 in. This is why we use a machine that injects smoke into the system. Do you know if this has been done?
~Michael (Dartman69)


not to my knowledge, if they did then they didnt tell me


Here is some info on how the EVAP system works. Pay close attention to page 3. Disregard my earlier post about creating a vacuum in the tank. It appears that through 99 Toyota used a non-intrusive EVAP system. Hope this helps.
~Michael (Dartman69)


Is your CEL still on? If so go to one of your local auto parts store and have them pull the code numbers. If they give you a description of what it is then ask them specificly for the code number and post it here. With that we might be able to make sure it is in your EVAP system or not.