SES/MIL light musings

[carwilef7]

Has anybody tried interrupting the MIL circuit to the ECM to install a switch? I don't want it glaring in my face all the time, but I would like to be able to read it out occasionally.

 

I keep getting a P0420/0702 - R cat efficiency code, and I've determined that I don't need a smog test in my part of VA. I do, however, find the MIL annoying, and it doesn't look good if you go in for a safety inspection (same theory that they'll do better work if your vehicle is clean inside and out - looks like you're particular). I would still like to be able to flip it on if something goes nuts and the truck starts running bad while on the road. Lost an engine in my last car and the light was flashing for about 20 seconds before it locked up solid.

 

I fail to see the point in spending big $$$ to replace the cat. The FSM and Haynes both show that the light is fed off a 10A bus with some other stuff in the dash cluster, and the ECM apparently just closes a contact to ground when a code is set, but I just want to make sure I'm not going to fry something inside it if I interrupt that circuit.

 

I've also been trying to run the truck hot - O/D off and 3000 rpm for several minutes at a time - to try to burn off the gunk that remains in the cat after a bunch of fuel mix issues - all of which are resolved now. Seafoam helped - and actually made it stop throwing a code for the L rear O2 sensor., and I think that code was also a result of the fuel goofiness. I still get the 0420 code after resetting and going about 100 miles, though.

 

Anyway - any ideas appreciated!

[keelhaul]

you could try and use a spark plug non fouler(here) to move the 02 sensor out of the exhaust stream. cheap trick might work

[carwilef7]

Thanks! I'll look into that.