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P0420 Diagnostic Trouble Code Discussion for May 2008

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2002 Chevrolet Camaro Z28 SS 5.7L Misfire VIN: 2G1FP22G92
P0420: Catalyst System Low Efficiency. This vehicle came in with a check engine light on, and I found two codes. PO300 random misfire and PO420 catalyst efficiency bank 1. I found and repaired the vacuum leak on the pcv harness. I also found a dirty MAF sensor (K&N), I cleaned the sensing eleme...
May 05, 2008
2002 Chevrolet Camaro Z28 SS 5.7L Misfire VIN: 2G1FP22G92
P0420: Catalyst System Low Efficiency. This vehicle came in with a check engine light on, and I found two codes. PO300 random misfire and PO420 catalyst efficiency bank 1. I found and repaired the vacuum leak on the pcv harness. I also found a dirty MAF sensor (K&N), I cleaned the sensing eleme...
May 06, 2008
2003 Nissan Pathfinder SE 3.5L MIL Lamp on VIN: JN8DR09483
P0420: Catalyst Efficiency Below Normal (Bank 1). ... for dtc p0420 and p0430 i found rear exhaust tubes leaking and muffler craked i repaired the exhaust leaks and reset the mil. mil light returned on the next day. with the same codes p0420 p0430. now from the data stream i see the up stream 02 switching fro...
May 13, 2008
2003 Pontiac Grand Prix SE 3.1L MIL Lamp on VIN: 1G2WK52J73
P0420: Catalyst System Bank 1 Low Efficiency. installed used motor(low mileage motor)with no problems. after 5k check engine came on po420. downstream o2 sensor looked sluggish, replaced it. came back shortly after with check engine on again po420. watched o2 sensors cat looked dead, replaced with afterma...
May 19, 2008
1999 Honda Odyssey EX 3.5L Stall VIN: 2HKRL186XX
P0420: Catalyst Efficiency Below Threshold (Bank 1). driven vehicle 50 miles unable to recreate stalling scanned for codes found above cannot find what area problem is in fuel pressure and flow good crank sensor scopes good cust say it is getting worse engine will start right back up after stall and may go 2 mil...
May 20, 2008
2001 Chevrolet S10 2.2L MIL Lamp on VIN: 1GCCS19501
P0420: Catalyst System Low Efficiency. This truck came in with new plugs and wires, new O2 sensors, converter. Code. PO 420 converter efficiency. The truck runs and idles great, the front 02 looks good on the scope, the rear O2 stays below one volt and has intermittent spikes. I have never seen a r...
May 21, 2008
1999 Toyota 4Runner SR5 3.4L MIL Lamp on VIN: JT3HN86R5X
P0420: Catalyst Efficiency Below Normal (Bank 1). This truck intermittently pops a check engine light. customer says it seams to happen after filling the tank. Drove the car rear o2 fluctuates some, more than it should. Front a/f sensor fluctuates some, but doesn't seam like it's enough,to me. How much is the...
May 29, 2008
2002 Chevrolet Camaro Z28 SS 5.7L Misfire VIN: 2G1FP22G92
P0420: Catalyst System Low Efficiency. This vehicle came in with a check engine light on, and I found two codes. PO300 random misfire and PO420 catalyst efficiency bank 1. I found and repaired the vacuum leak on the pcv harness. I also found a dirty MAF sensor (K&N), I cleaned the sensing eleme...
May 05, 2008
2002 Chevrolet Camaro Z28 SS 5.7L Misfire VIN: 2G1FP22G92
P0420: Catalyst System Low Efficiency. This vehicle came in with a check engine light on, and I found two codes. PO300 random misfire and PO420 catalyst efficiency bank 1. I found and repaired the vacuum leak on the pcv harness. I also found a dirty MAF sensor (K&N), I cleaned the sensing eleme...
May 06, 2008
2003 Nissan Pathfinder SE 3.5L MIL Lamp on VIN: JN8DR09483
P0420: Catalyst Efficiency Below Normal (Bank 1). ... for dtc p0420 and p0430 i found rear exhaust tubes leaking and muffler craked i repaired the exhaust leaks and reset the mil. mil light returned on the next day. with the same codes p0420 p0430. now from the data stream i see the up stream 02 switching fro...
May 13, 2008
2003 Pontiac Grand Prix SE 3.1L MIL Lamp on VIN: 1G2WK52J73
P0420: Catalyst System Bank 1 Low Efficiency. installed used motor(low mileage motor)with no problems. after 5k check engine came on po420. downstream o2 sensor looked sluggish, replaced it. came back shortly after with check engine on again po420. watched o2 sensors cat looked dead, replaced with afterma...
May 19, 2008
1999 Honda Odyssey EX 3.5L Stall VIN: 2HKRL186XX
P0420: Catalyst Efficiency Below Threshold (Bank 1). driven vehicle 50 miles unable to recreate stalling scanned for codes found above cannot find what area problem is in fuel pressure and flow good crank sensor scopes good cust say it is getting worse engine will start right back up after stall and may go 2 mil...
May 20, 2008
2001 Chevrolet S10 2.2L MIL Lamp on VIN: 1GCCS19501
P0420: Catalyst System Low Efficiency. This truck came in with new plugs and wires, new O2 sensors, converter. Code. PO 420 converter efficiency. The truck runs and idles great, the front 02 looks good on the scope, the rear O2 stays below one volt and has intermittent spikes. I have never seen a r...
May 21, 2008
1999 Toyota 4Runner SR5 3.4L MIL Lamp on VIN: JT3HN86R5X
P0420: Catalyst Efficiency Below Normal (Bank 1). This truck intermittently pops a check engine light. customer says it seams to happen after filling the tank. Drove the car rear o2 fluctuates some, more than it should. Front a/f sensor fluctuates some, but doesn't seam like it's enough,to me. How much is the...
May 29, 2008