Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Evap in in my 2006 monte carlo

hi i had a ex friend(now) hook his machine up to car when check engine light came on and he said the machine spit back that it was a large evap leak but didnt give me what the codes were that came back. now were not talking but i tried to change out the gas cap after i did that the check engine light went off for a day after a put in new gas cap then it came back on and has been back on since. any thoughts as to what it could be from? and is it safe to still drive?

Without knowing if it is the same code as last time it would be a guessing game. After all it could be a new and different code.

Evap codes are rarely dangerous, I’d go to a nearby auto parts store and have them read the codes, let us know what they are.

I can tell you that there’s not likely a safety concern unless the code suggests something that might cause you to break down in a crime-ridden area, but without codes impossible to do anything other that wildly guess. Follow Texases’ advice. Have the codes read and post them here.

I’ll WA guess it was a DTC like P0455, which would cause some folks to recommend the cheapest, easiest fix, a new gas cap.

Since this car is 10 or 11 years-old now, and I’m not sure if run in the rust belt portion of the country or not, I’d recommend looking carefully at the surface of the fuel-filler pipe where the gas cap seal contacts it when tightened into position. I have seen rust on that area on some cars that has triggered the same code(s) (P0442, P0455) that a leaking cap sets off.

Unless that narrow surface is shiny metal, clean it off. Try and keep debris out of the gas filler. I put a rag in the opening, first. Keep in mind that sparks and gasoline are a bad combo and clean with something that won’t spark. Also, wipe the gas cap seal. I apply WD-40 to the cap seal when reinstalling the cap.

If the purge valve can’t pull a vacuum at all . . . not uncommon on some GM vehicles . . . that will lead to a large leak evap code

what I’m saying is this . . . sometimes the purge valve can’t pull a vacuum because the valve itself is faulty. Not uncommon, as I said

But somebody should definitely diagnose this

Throwing parts at it can get to be expensive, unless you guess cheap and correctly the first time

This might provide some help so you can better discuss this w/your shop. It likely isn’t a big, expensive problem, but needs to be fixed.