Manager Forum

As usual, thanks in advance for any help you can render. I have a 1999 chev k1500, 5.7 that runs fine. I have an evap p1443 & P0420 code. I have negative fuel tank pressure?, purge valve is opening & closing properly, no leaks & vent valve is closing and in mode 6 i show 2 component tests that have failed miserably. My downstream o2s are switching as fast as the front ,and in mode 6 it says test id # 07 components OC & OD have failed. My thinking was that these are the 2 downstream o2s, but i'm not sure. Is there any sites that offer mode 6 information reasonably. Joe Gallagher.....down in Nashville scratching his head again

The rear o2's are switching like the front when driving? If so the cat?

Joe, mode 6 is available in Mitchell under engine performance. Found test 7 0c egr off idle test or maf out of range. 0d idle test or maf out of range low. Mode 6 is also found on iATN. HTH, Jeff

Joe, I often resort to Mode 6 when doing Emissions testing or anything to do with fuel evaporation issues. The info from Mitchell1 usually helps me diagnose the problem. Based on my experience I would say that with some experience you will also resort to it more in the future.

did the customer mention that the truck has exibited an occasional loss of power or intermitant stall? another quick question would be has the fuel guage acted erratic a times. i've run into wiring issues with these beauties before. the harness fails at the pump or at the transmission crossmember.

DUH!!!!!!!!! Thanks for the info about mode 6 in Mitchell. I never saw it before , but I still didn't find any info about test ID #07??? Cat fixed the 420 code, I was pretty sure about that one. 1443 code was repaired with purge valve, the valve was leaking internally, didn't find it until I smoked tested it off the vehicle. THANKS AGAIN FOR HELPING OUT GUYS.

Mode 6 is not the techs magic pill we wish we had at times but rather I see it as another tool to assist me in getting info so I can make a proper diagnosis. I find Mode 6 being very useful in diagnosing intermittant misses before a pending code can be picked up. Also, as I said, EVAP testing as well as emissions in a post cat monitor. And, the newer the vehicle, the more useful the Mode 6 info.

Thanks for sharing. Glad we can learn from each other.

Thx for posting the fix. I knew the cat was bad when you said the rear o2 was switching just like the front almost always a cat