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P0421 Diagnostic Trouble Code Discussion for July 2011

Warmup Catalyst Efficiency Low (Bank 1)


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Trouble Ticket Help Requests for DTC P0421
Help Request Posted
2003 Saturn Vue 3.0L Misfire VIN: 5GZCZ63B73
P0421: Warmup Catalyst Low Efficiency (Bank 1). Customer came in with vehicle that had codes. Po300 random misfire,[...] #1 misfire,po421 cat eff. low bank 1,p2b03 which I cannot find any info on.I monitored bank 1 o2 sensors and rear o2 mimicing front so I assume cat is faulty.I checked spark plugs and wer...
July 27, 2011
2003 Saturn Vue 3.0L Misfire VIN: 5GZCZ63B73
P0421: Warmup Catalyst Low Efficiency (Bank 1). Customer came in with vehicle that had codes. Po300 random misfire,[...] #1 misfire,po421 cat eff. low bank 1,p2b03 which I cannot find any info on.I monitored bank 1 o2 sensors and rear o2 mimicing front so I assume cat is faulty.I checked spark plugs and wer...
July 28, 2011
2003 Saturn Vue 3.0L Misfire VIN: 5GZCZ63B73
P0421: Warmup Catalyst Low Efficiency (Bank 1). Customer came in with vehicle that had codes. Po300 random misfire,[...] #1 misfire,po421 cat eff. low bank 1,p2b03 which I cannot find any info on.I monitored bank 1 o2 sensors and rear o2 mimicing front so I assume cat is faulty.I checked spark plugs and wer...
July 27, 2011
2003 Saturn Vue 3.0L Misfire VIN: 5GZCZ63B73
P0421: Warmup Catalyst Low Efficiency (Bank 1). Customer came in with vehicle that had codes. Po300 random misfire,[...] #1 misfire,po421 cat eff. low bank 1,p2b03 which I cannot find any info on.I monitored bank 1 o2 sensors and rear o2 mimicing front so I assume cat is faulty.I checked spark plugs and wer...
July 28, 2011