First - DTC P0420. It keeps showing up. Have run cataclean thru it and still illuminates. Is there a way to trick the ECM so it don’t come on anymore??

Second - Dual piston calipers. I’ve read somewhere that dual piston calipers would fit the Bonneville… true or false. If factual, what donor vehicle would I need to get them from and would I need the caliper mounting bracket?

Thank you for taking the time to read this post. All advice and help is greatly appreciated.

The electrical O2 spoof solutions were all shut down and taken to court for the most part. Mechanically you could try an O2 sensor spacer but I would just replace the sensor to start since it sounds like you have a cat.

There are many front brake options with varying degrees of effort to retrofit. Search this site for brake upgrades and also search w-body front brake upgrades since the front knuckles are the same wrt hub/brake mounting.

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95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers

Info on dropping a 92-99: Here.

I've tried o2 spacers without success. Just plan on getting a new cat. I recommend the Magnaflow 33906HM. Don't waste your time/money on any cheap Chinese cat as they will set the CEL as well.

Bonneville GXP brakes or W-body brakes are the upgrade you're hearing about. For the GXP upgrade, you need: the bigger rotors, the caliper brackets and the special collared bolts that hold it to the knuckle, the dual piston calipers and also the brake hoses. Pretty simple upgrade.

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Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler

You can use HPTuners to remove the code as well.

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-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

Are the said items for the GXP brakes available online?

I have used options, although you can easily source it all brand new.

Pads, rotors, calipers, brackets and hoses will all be available from any parts store or Rockauto

Bracket bolt: 89047763 ($5 each at the dealer, need 4)

_________________
Andrew - owner/operator of Bonnevilles Unlimited

2004 Bonneville GXP | 60k | White Gold Tricoat | custom built supercharged 3800 hot rod | garage queen
1997 Corvette | 57k | Silver Metallic | Z06 wheels | Date-night Hauler/Parts runner
2014 Town & Country Limited | Cashmere Pearl | 115k | Family Hauler
2002 Ram 1500 Quad Cab Sport | Black| 280k | Official Bonneville Hauler