shelbycobra79

A few weeks ago my car was at the dealer for some issues. One thing they found was an engine code that pertains to the EGR system. We didn't dive into searching for the specific issue yet. The engine light will come on but then goes off on its own. I finally realized that the light is coming on when my gas gets below half a tank and goes off when I put more gas in. Does anyone have any idea what would be causing this? Not sure if it relates to the EGR code or not. Hoping to be able to pinpoint what needs to be repaired without the hours of diagnostics at the dealer.

Jeff Collision

There is a good possibility that you have a problem with the evaporation system in the fuel tank that is activated when the fuel is low. You will need to have the codes pulled out of the computer at a time when the light is on to get to the bottom of it and find the problem. The engine light comes on to tell you that the computer has sensed a problem with a component in the engine control or emission system. When the light comes on the computer stores a code related to the failed component. This code can be retrieved with a scan tool, once the code has been detected you will get a pretty good idea of what part or sensor has caused the problem. Even if the car is still running well, the system should be scanned to be sure that you are not causing damage to the motor or other related parts. Sometimes it is something as simple as a broken connection or leaking vacuum hose or loose gas cap.

Chevrolet Customer Service

shelbycobra79,

Yes, Jeff has made a great point. The light comes on to indicate a concern it is detecting. I recommend you have the codes pulled, just to make sure there is not something else as well.

Erica Tiffany
Chevrolet Customer Care

shelbycobra79

I definitely want to find out what is wrong so I can get it fixed. I just couldn't afford to pay $90/hr at the dealer for them just to determine the problem then also pay a repair bill.

I had the code read today and was told P0405 Exhaust Gas Recirculation Sensor A Circuit Low. I've searched on-line about that code and see there could be a few things that cause this code but the general information I got was to change the EGR valve first. The part is only $75. Is it a safe assumption to go that route first and is it a fairly easy repair that we can do at home? I've grown up working on cars with my dad so I'm pretty comfortable taking on realistic at home repairs.