2002 Chevy Tahoe check engine light

ALBERT MCLAUGHLIN

MEMBER
2002 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
122,672 MILES

Engine replaced with new at 85,000. Current odometer, 122,672. Since engine replaced, "check engine" light comes on after several hours of high speed Interstate driving. Once lit, stays on for hours, even overight. All gages read properly. Have called "on-star" for diagnostics. They found no problems or engine misfire. Light went out before taking car to GM service. GM ran diagnostcs test and found no problem. Have not been able to make light come "on" with local driving but it reoccurs after one or two days of long distance travel.
Do you have any suggestions for "most probable" cause.
Can you recommend an inexpensive code reader so I can read the trouble codes related to the "check engine" light and reset the trouble light.

1 Reply

MASTERTECHTIM

MECHANIC
4,749 POSTS

I KNOW INSUFFICIENT EGR FLOW AT STEADY THROTTLE POSITION, LIKE DRIVING ON HIGHWAY. CAN CAUSE THIS TYPE OF PROBLEM BUT THERE SHOULD HAVE BEEN A CODE STORED AND ONSTAR SHOULD HAVE PICKED UP ON IT. ONCE THE LIGHT TURNS OFF BY ITSELF, IT IS TELLING YOU THAT THE PROBLEM NO LONGER EXISTS AND THE VEHICLE HAS PASSED THAT CIRCUITS TEST A NUMBER OF TIMES AND IT PASSED.