The box that contains the diagnostic receptacle has been invaded by mice and they have shredded some of the wiring in there, causing rough running and a CE light.

I want to replace the chewed wires but I need to remove some of the plugs and plastic boards holding fuses and other plugs to get to the damaged wiring.

Assuming that I put it back the way it was, will I screw something up (electronically) by just disconnecting the stuff in the box to get to the damaged wires?

Also, my California car w/256,000 mi, cat converter makes rattling sounds at idle, esp when put in gear and held with the brakes. Goes away when engine is revving, so it appears that the cat rattle resonates at lower frequencies. Suspect something came loose inside the CC. Prices for a CatCon vary from $70-500+. Suggestions?

Your mouse problem should be covered by the comprehensive part of your insurance.

I went ahead and unplugged a few things and patched up the wiring. CE light is gone and car seems to run fine.

My deductible is $500. Insurance is basically worthless unless you have a catastrophic loss. I'm going to install an electrified horse fence around each wheel about 3/4" off the floor. Car can roll over the wire. Cost is $30 and Should keep the little bastards out of the car.

I had a mouse in mine also. I wonder why they prefer the C series? They must read Consumer Reports... Anyway, I tried a trap with PB on it but they were too smart for that. So I got some of those traps with the big yellow plastic paddle on them. I just put a couple where I though they would be running by. Sure enough he ran right over it. No bait.

As far as the cat, mine was like that also. If you want to diagnose for sure, get a rubber mallet and tap on each cat and you will hear which one is rattling (or both). You can get aftermarket cats but I would stay away from Catco.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra

We had a mouse problem a while back... Warfarin bait works wonders... they take it to their nest and snack on it later.. a day or two later they bleed to death internally...

Subsequent mice find that stash and eat... They perish as well... The gift that keeps on giving...

Wifey takes Coumadin which has the same active ingredient (A Blood Thinner) she refers to it as her rat poison...Lol

DCON or something similar works wonders... and keeps the population down...Read the labels if you have house pets, or little kids that may eat it...