po157

2004 chevy 4+4 2500 pulled code po157. Was driving down highway pulling a 27 ft travel trailer and engine light came on but no change in driving got home ok engine light stayed on all day after the 2nd day on the way to have it checked light cleared itself any ideas

try your gas cap on the side of the truck one time i didnt close it properly and my truck Check Engine Light was on all day cuz of it

wouldnt it have been a different code for that??

Two possible casues. Bad o2 sensor; rear, bank 2. Or you could have an exhaust leak between the engine and the sensor.