So I bought this 2002 s40 for really cheap last fall. I replaced a few things (mainly brakes, exhaust mid pipe) but it won’t pass inspection for a bunch of evap leaks and the dreaded p0420 code (need to replace the cat) but it runs and drives rather well.
its truly a pos, but it’s a running driving vehicle that gets me around. If I could get a nysi sticker for it somehow (wink wink pm me) I would just keep it. But not if I have to put $1000 into a $400 winter beater (thanks NYS)
i have an absurd summer daily driver and can go buy a newer sensible car tomorrow if I had to. I just like not having a car payment.
I only know of a resistor mod for 850/855s and S70/V70s. From what I understand, first gen S40s are a pain in the dick. I’m on Volvoforums and Swedespeed, so I’ll see what I can dig up.
Well, P0420=
The control module continuously checks three-way catalytic converter (TWC) efficiency by comparing signals from the rear heated oxygen sensor (HO2S) with the front heated oxygen sensor (HO2S). Diagnostic trouble code (DTC) ECM-4801 (on VADIS) will be stored if the efficiency of the three-way catalytic converter (TWC) deviates too much.
Substitute value-
Rear heated oxygen sensor (HO2S) control is disabled.
Possible causes?
-misfiring
-air leakage in the intake system
-air leakage in the exhaust system
-faulty fuel pressure
-uneven compression
-defective three-way catalytic converter (TWC).
I’d try and track down the causes of the other stuff first.
Forgive me if I have no fucking idea what Im talking about but here’s what I did last year and it worked. no idea how or why but Im going to try it again soon. Clear codes/disc battery to get the computer to have to relog the codes. go get it inspected FTMFW. I disc’d the battery(thought battery was bad) and while the light was off, i went and got it inspected. Passed with no issues. The next fucking day the light came back on.
PS i have the same cat code and really dont plan to replace it
You got lucky. The computer has to show a certain amount of readiness monitors set (which all get cleared when you clear the CEL) or the computer won’t even let them print out a sticker. You must have tripped just enough monitors to pass but not yet done the EVAP test that was triggering the CEL.
I had made the most absurdly accurate Photoshopped inspection sticker once upon a time. I’m much older and wiser now to play those games, but it worked like a charm for a little while!
