Tip & How-To about Pontiac Cars & Trucks
Thanks to neglecting the engine light (due to a bad purge valve - see my answer on that) I got code 430 indicating Bank 2 Catalytic Converter below threshold. My wife took it to a shop, who quoted $900 for the part, and $200 to install it. They said we needed the genuine GM part. Bank 2 is the front one.
I went to the dealer (Momentum Chevrolet in San Jose) and they wanted $849 for the part. This is the front one, and it comes complete with pipes and flanges.
I ordered one online for $560 + $100 refundable core charge from gmpartsdirect.com.
Replacing it was easier than I expected. I borrowed car ramps from my son, to get the front of the car about 8" higher.
First, you have to remove an air duct which connects the engine air filter to the fuel injection. It's about a 5" diameter long tube at the top just behind the radiator. Loosen 2 hose clamps and remove a bolt and one vacuum line to the crankcase.
Once that's off, you will be able to look down and see a heat shield. Remove 3 10mm bolts and move the shield out of the way. Get some Liquid Wrench and wet the 3 nuts that hold the cat flange to the exhaust manifold. Remove the 3 nuts. The studs may come out with them, but you can separate them later.
Then get under the car, nd you will be able to look up and see the O2 sensor which is threaded into the pipe just below the cat. Wet it with liquid wrench (I used a teaspoon to get it up there). I was able to loosen it with a crescent wrench. Unplug the cable before screwing it out.
Lastly, there are two 1/2 nuts holding on the flange on the other end. Again use Liquid Wrench to get those off. I had to tap the studs with a hammer to loosen the connection. Now, to get it off, you need to pull this flange forward, compressing the flexible connector.
Installing is the opposite of all these steps. Put the front end up in there first, if you have a helper to apply one or more of the nuts to hold it up that would be good. (I didn't) Then to get the back end in, you again need to pull the flange forward, compressiing the flex joint.
Tighten the nuts, reinstall the O2 sensor, put the heat shield and air tube back on, and you're finished. Relatively easy, compared to what I expected. That was yesterday, and today it passed smog! And the exhaust smells much nicer. And I saved $550! Just mailed the old part back to get my core charge back. Cheapest way was USPS ground - $24 with insurance. Printed the label using Paypal. No standing in line at the post office.
Posted by Martin... on
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P0431 Warm up catalytic converter, bank 2 - efficiency below threshold
Possible causes: Catalytic converter, wiring, HO2S 2
Usually caused by worn out catalytic converter, but always check fuel pressure regulator for proper operation before replacing a converter.
P0446 Evaporative emission (EVAP) system, vent control -circuit malfunction
Possible causes: Wiring, EVAP canister purge valve, ECM
May be caused by a loose or disconnected wire to the vent valve or possibly a bad valve solenoid
If you would like part locations, troubleshooting or replacement procedures, please let me know.
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