So my 2008 H3 check engine light came on a few months ago. Instantly i asked a friend to have his mechanic look at it and diagnose the issue. It was the Fuel Cap/EVAP code that came back. The mechanic informed me buy a new fuel cap for pennies and start there, otherwise it may be some hose or gauge i vaguely remember but it was under the left rear tire as he pointed out. I bought a new fuel cap, and the check engine light was off for 200 miles exactly. So its been back on for the past few weeks and as im driving the other day as my SERVICE TPM/LOW TIRES continues to stay on day in and day out (which all my tires are exactly at the proper PSI with brand new Bridgestone Dueler Alenzas on), it switched back and forth with SERVICE TPM and FUEL CAP. I dont wanna get robbed at a mechanic even if he is a friend of my childhood friend, everyone is out for a quick buck, but i also cant continue to drive around any longer with my CEL on either. Someone either tell me i have no choice get it fixed or is there an alternative. Please help, thank guys.

 

As far as tpms it sounds like one of your sensors is out of commission.
The batteries are sealed in there and after about 4-5 years they give out,
so spend some dollars to replace them.
As far as the cell get it diagnosed and solve the problem. Cars cost money unfortunately.

 

My engine light will come on at the very sniff of gas. Always make sure you turn off the engine at the pumps. Was filling lawn mower just outside the garage and the next day the light came on again. EVAP code small is the reading. I bought on Amazon, based on another forum with same issues (Autel MaxiScan MS300 CAN Diagnostic Scan Tool for OBDII Vehicles) for around 20.00 and I keep it in the car and when the light goes on I plug it in and hold the scroll button for 3 seconds and the light is gone till the next time one of the sensors sniffs some gas. I think a mech told me that there were about ten sensors through out the car and that what I am doing is a lot cheaper then trying to find what o2 sensor is bad. Good Luck