Re: 99 GMC Z71
I'm getting the exact same thing in my 99 Silverado Z71, And it is real random, sometimes it just comes on for no reason. I'm taking it to get it hooked up to a scan tool when I got on Spring break in two weeks. But someone told me that, the light didn't have to be on to check it, because the PCM stores all trouble codes until the system is reset. Let me know if you get it fixed or what is causing the light.