2000 RAV 4 P0420 4 cyl Man

[Idahome]

My check engine light came on today, diagnostic device gave a P0420 Catalyst System Efficiency Below Threshold (Bank #1). I've got 140,000 on the RAV. All written indicators tell me either O2 sensor or Cat, is there a easy/cheap way to determine exactly what it is before I put out the cash to fix it? One thing I've noticed is the fuel efficiency seems to have gone down quite a bit.

Thanks

[mral1515]

Check to make sure there are no open recalls on your vehicle. There is a recall that could possibly take care of that. If you PM me your VIN I can check for you.

Matt

Originally Posted by Idahome

My check engine light came on today, diagnostic device gave a P0420 Catalyst System Efficiency Below Threshold (Bank #1). I've got 140,000 on the RAV. All written indicators tell me either O2 sensor or Cat, is there a easy/cheap way to determine exactly what it is before I put out the cash to fix it? One thing I've noticed is the fuel efficiency seems to have gone down quite a bit.

Thanks

[Idahome]

Originally Posted by Idahome

My check engine light came on today, diagnostic device gave a P0420 Catalyst System Efficiency Below Threshold (Bank #1). I've got 140,000 on the RAV. All written indicators tell me either O2 sensor or Cat, is there a easy/cheap way to determine exactly what it is before I put out the cash to fix it? One thing I've noticed is the fuel efficiency seems to have gone down quite a bit.

Thanks

I'm going to start with replacing the inexpensive stuff first but I can only find 1 O2 sensor on my exhaust system. The one I found is down stream of the catylatic converter, does anyone know where the other one is? My Haynes manual show 2 sensors but not in the place they're actually at. Also, does anyone have a good way to get the rusted nuts undone? I sprayed penatrant on them and they still won't budge.

Thanks

[Tundradrenalin]

Try some PB Blaster penetrating lube, let it sit a few hours after a good soaking, and then use a longer ratchet or a breaker bar. Since you've got 140k on them already, be prepared to break some nuts/bolts. A good source for part#'s is toyodiy.com. Has exploded diagrams for most every Toyota vehicle. Check it out!

[kathyricks]

The P0420 Catalyst System Efficiency Below Threshold check engine light seems o be commonly showing up nowadays on the late 90's and early '00 Toyotas at around 90,000- 150,000 mile mark. Sometimes replacing the oxygen sensor in front of the cat makes the light go away, other times it doesn't and the converter has to be replaced.

Prevention is the strategy that will likely avoid future wallet shocking P0420 lights; i.e. you need to do what you can to reduce the concentration of unburned hydrocarbons the engine generates and which enters the cat. The way to do that is to monitor your fuel economy and start replacing or cleaning parts as needed to restore fuel economy; e.g. changing the air filter, spark plugs and cleaning the throttle plate of deposits. And avoid cat destroying practices like frequent full throttle acceleration and adding engine mods like aftermarket air intake and exhaust system mods. And never use aftermarket parts of any kind (e.g. spark plugs)

[Idahome]

Originally Posted by Tundradrenalin

Try some PB Blaster penetrating lube, let it sit a few hours after a good soaking, and then use a longer ratchet or a breaker bar. Since you've got 140k on them already, be prepared to break some nuts/bolts. A good source for part#'s is toyodiy.com. Has exploded diagrams for most every Toyota vehicle. Check it out!

Got 3 of the 4 cat bolts loose, I had to drill a 1/4 hole side ways in the head of the 4th one and them I put a philips screw drive shaft through the hole, put a leverage device on the screw driver handle and broke it loose . Hopefully new parts will be here this coming week and I'll get her back together and back on the road without a P0420 indication.

Thanks for the advice.

[Idahome]

Originally Posted by kathyricks

The P0420 Catalyst System Efficiency Below Threshold check engine light seems o be commonly showing up nowadays on the late 90's and early '00 Toyotas at around 90,000- 150,000 mile mark. Sometimes replacing the oxygen sensor in front of the cat makes the light go away, other times it doesn't and the converter has to be replaced.

Prevention is the strategy that will likely avoid future wallet shocking P0420 lights; i.e. you need to do what you can to reduce the concentration of unburned hydrocarbons the engine generates and which enters the cat. The way to do that is to monitor your fuel economy and start replacing or cleaning parts as needed to restore fuel economy; e.g. changing the air filter, spark plugs and cleaning the throttle plate of deposits. And avoid cat destroying practices like frequent full throttle acceleration and adding engine mods like aftermarket air intake and exhaust system mods. And never use aftermarket parts of any kind (e.g. spark plugs)

Thanks for the info...how do I clean the "throttle plate of deposits"?

[bepperb]

Usually the throttle plate gets cleaned when you clean out the idle air control valve, and on newer cars the maf sensor. Basically, the PCV spills crankcase gasses upstream of them, and over time they can get gummed up with deposits. Do some searches on camry IAC valve cleaning and you'll find what KathyRicks is talking about, but I'm not certain it applies to your exact situation (but probably worth taking a look at with your mileage and current problems).

I think you're on the right track of replacing the o2 sensors first. Likely that's the cause. If the cat is bad usually you'll get significant power loss at mid/high rpm and rotten egg exhaust smell, neither of which you've mentioned. The 420 is a catch-all code, though, so you never really know.