Want this question answered?
after exhaust manifold, before catalytic converter.
p134
On my 99 Grand Prix 3.8 it's located below the rear exaust manifold on the engine block.
This answer is from the Haynes Repair Manual for GM Pontiac Grand AM 1999 and 2000 1st coil terminal as you stand at front of car L>R 5-2-3-6-4-1 2nd firing order of sparkplugs as you stand at front of car L>R rear bank (towards firewall) 1-3-5 front bank L>R (side to radiator) 2-4-6 (this is for the 3.4L V6--204cubic inch engine)
Answerfront bank (radiator side) 2-4-6 rear bank 1-3-5 Info from a 03 grand prix se 3.1
Trouble code P0420 means: Catalyst System Low Efficiency (Bank 1)
bank one is before the catalitic converter, or the front sensor ( on the front exhaust manifold)
your bank 2 sensor is the o2 sensor on your passenger side exhaust manifold
Grand Bank was created in 1943.
The population of Grand Bank is 2,580.
The area of Grand Bank is 16.97 square kilometers.
Bank 1 is usually the bank that #1 cylinder is on (sometimes the driver side while bank 2 is the passenger side) and sensor 1 is before the cat converter while sensor 2 is after the converter.