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P0420 Diagnostic Trouble Code Discussion for March 2012

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2006 Chevrolet Express 1500 4.3L MIL Lamp on VIN: 1GCFG15X46
P0420: Catalyst System Low Efficiency (Bank 1). ... problem is it not power under load at all.the van in park or nutral runing smoth and normal,raise rmp normal but when i put the car in drive or reverse no power at all,somebody cleaner catalyst both sides that why i have code po420 and p0430.when i put the...
March 01, 2012
2006 Chevrolet Express 1500 4.3L MIL Lamp on VIN: 1GCFG15X46
P0420: Catalyst System Low Efficiency (Bank 1). ... problem is it not power under load at all.the van in park or nutral runing smoth and normal,raise rmp normal but when i put the car in drive or reverse no power at all,somebody cleaner catalyst both sides that why i have code po420 and p0430.when i put the...
March 02, 2012
2007 Suzuki Forenza 2.0L MIL Lamp on VIN: KL5JD56Z97
P0420: Catalyst Efficiency Below Normal (Bank 1). ... suzuki,forenza.that keeps popping code p0420 after few drive cycles.i removed cat and inspected.looked very clean from in side.no other codes or issues with car.car runs great.any help will be greatelly appreciated.thanks in advance.
March 07, 2012
2000 Pontiac Bonneville SSEi 3.8L Stall VIN: 1G2HZ5417Y
P0420: Catalyst System Low Efficiency. car runs fine when it's running,but will randomly shut off at any time. it will restart immediately and run sometimes for hours with no problem. anyone got any idea's how to narrow down the culprit. thanks in advance.
March 21, 2012
2004 Volvo XC70 2.5L MIL Lamp on VIN: YV1SZ59H84
P0420: Cat effiencey. ... the customer said she was at the dealer and they said she needed a cat. I scaned the ecm and found codes P2187 Lean bank 1 and a P0420. I found a very large vacuum leak, I fixed that and cleared the code and had her drive it to see if the P0420 comes back....
March 22, 2012