1999 Chev K1500 - Mode 6 Info FIXED

[joetngallagher]

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

[brianp87]

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

[Jeff @ Able Auto]

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

[Tim Martin]

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.

[steven kiser]

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.

[joetngallagher]

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.

[Tim Martin]

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.

[brianp87]

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