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P0420 Diagnostic Trouble Code Discussion for February 2005

Catalyst Efficiency Below Normal (Bank 1)


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Trouble Ticket Help Requests for DTC P0420
Help Request Posted
2000 Toyota Corolla CE 1.8L Stall, MIL Lamp on VIN: 1NXBR12E51
P0420: Catalyst Efficiency Below Normal (Bank 1). ... complaint is that the mil lite comes on while driving-when coming to a stop the car may stall-codes p0172-po420 are coming up-also for sure the exhaust manifold is leaking-could that affect the drivebility of the car?-or is there something else thats commo...
February 02, 2005
1996 Ford F-250 XL 4.9L No Start, Stall VIN: 1FTEF25Y1T
P0420: Catalyst system effieciency Bank one. Hello everyone, This truck has been giving us fits for the last month or so. Every time we get the truck in the shop off the wrecker or go to look at it seem to be okay. Recently stalled while driving and would not restart. Found no spark condition with no sig...
February 03, 2005
2001 Chevrolet Impala LS 3.8L p0420 VIN: 2G1WH55K81
P0420: Catalyst System Low Efficiency. Have run car on Modis and shows OK. Fuel at speed looks good. Map and maf in range. LT fuel trim show -6 to -2 as you drive down the road log flat strech shows +2 to -3. Temp OK timing and all els look in spec. What have I missed?
February 07, 2005
1996 Ford F-250 XL 4.9L No Start, Stall VIN: 1FTEF25Y1T
P0420: Catalyst system effieciency Bank one. Hello everyone, This truck has been giving us fits for the last month or so. Every time we get the truck in the shop off the wrecker or go to look at it seem to be okay. Recently stalled while driving and would not restart. Found no spark condition with no sig...
February 07, 2005
2000 Nissan Sentra GXE 1.8L MIL Lamp on VIN: 3N1CB51D6Y
P0420: Catalyst Efficiency Below Normal. ... tested and found bad MAF, replaced MAF cleared codes. customer returned week later check engine light on. p0420 cat efficiency below threshhold bank 1. Tested Oxygen sensors, ok. Replaced with OE catalytic converter (out of...
February 08, 2005
2000 Chevrolet Suburban 1500 LT 5.3L Excessive Emissions, Misfire, MIL Lamp on VIN: 3GNFK16T3Y
P0420: Catalyst System Low Efficiency (Bank 1). Help!!! I've got this suburban that shows misfires on #1&6. I've checked backpressure and found none. No regulator leaking. I've swapped coils and wires. All injectors drop same pressure. Mis only happens between 2000 and 3000 rpms. The only way i know the...
February 09, 2005
1995 Ford Windstar GL 3.8L No Start VIN: 2FMDA5148S
P0420: Catalyst below threshold. First, thanks for any help offered.. I have an employees 95 3.8 Windstar van here that has an intermittent 'no spark' on initial crank/cold 'ONLY'.. Runs fine the rest of the day with 'no' starting/drivability issues once started.. It may fire off on the firs...
February 09, 2005
1997 Mazda 626 DX 2.0L high idle/hunts cold VIN: 1YVGE22C2V
P0420: Catalyst Efficiency Below Normal (Bank 1). ... warm), idle speed hunts when cold. Sometimes it does this, other times it is fine. At times the vehicle lacks power. Cruise control also does not work, however the cruise did not work before we replaced the engine. No codes in the computer related to this,...
February 09, 2005
2000 Chevrolet Suburban 1500 LT 5.3L Excessive Emissions, Misfire, MIL Lamp on VIN: 3GNFK16T3Y
P0420: Catalyst System Low Efficiency (Bank 1). Help!!! I've got this suburban that shows misfires on #1&6. I've checked backpressure and found none. No regulator leaking. I've swapped coils and wires. All injectors drop same pressure. Mis only happens between 2000 and 3000 rpms. The only way i know the...
February 10, 2005
2000 Lexus LS400 4.0L MIL Lamp on VIN: JT8BH28F8Y
P0420: Catalyst Efficiency Below Normal (Bank 1). ... in my shop with a dtc p0420.(catalyst efficiency below threshold bank 1) about 2 weeks ago this vehicle was at my shop with a dtc p0430 (catalyst efficiency below threshold bank 2)no other codes were stored nor did the customer have any drivability complai...
February 14, 2005
1995 Toyota Tacoma SR5 3.4L MIL Lamp on VIN: 4TAVN73K6S
P0420: catalyst efficiency bank 1. this thing sets a code p0420 about every 500 to 700 miles. freeze frame data shows the b1 s2 02 sensor switching mirroring b1 s1. in my shop with the modis on it every thing is working fine. the b1 s2 switching much slower as designed. thanks john
February 17, 2005
2002 Subaru Forester S 2.5L MIL Lamp on VIN: JF1SF65622
P0420: Catalyst Efficiency Below Normal (Bank 1). I need some help with this Subaru. Cleared code several times and always came back. As per mitchell on demand we checked for exhaust leaks, lowered and checked, visually , both converters, looked fine, check for damage on rear o2 shield wire, disconnected harn...
February 19, 2005
1997 Toyota Camry CE 2.2L MIL Lamp on VIN: 4T1BG22K5V
P0420: Catalyst Efficiency Below Normal (Bank 1). Emission failure. Sets P0420, Bank 1 Cataylst System Effieciency Below Threshold. When looking at O2 sensor voltage, the bank 1 O2 mv will not go below .650 mv. Can induce a vacuum leak and the O2 voltage will go to .900mv but when you ground a spark plug wire...
February 23, 2005
1999 Volkswagen Jetta GLS 2.8L Surge, Stall VIN: 3VWSE29M8X
P0420: Catalyst Inefficiency. ... to me after seeing many repair shops with little work done. The car has been in a collision before and had a poor attempt of an aftermarket radio installed which was corrected with a factory unit. Occasionally the EPC light will come on along with a buck...
February 26, 2005
2000 Toyota Corolla CE 1.8L Stall, MIL Lamp on VIN: 1NXBR12E51
P0420: Catalyst Efficiency Below Normal (Bank 1). ... complaint is that the mil lite comes on while driving-when coming to a stop the car may stall-codes p0172-po420 are coming up-also for sure the exhaust manifold is leaking-could that affect the drivebility of the car?-or is there something else thats commo...
February 02, 2005
1996 Ford F-250 XL 4.9L No Start, Stall VIN: 1FTEF25Y1T
P0420: Catalyst system effieciency Bank one. Hello everyone, This truck has been giving us fits for the last month or so. Every time we get the truck in the shop off the wrecker or go to look at it seem to be okay. Recently stalled while driving and would not restart. Found no spark condition with no sig...
February 03, 2005
2001 Chevrolet Impala LS 3.8L p0420 VIN: 2G1WH55K81
P0420: Catalyst System Low Efficiency. Have run car on Modis and shows OK. Fuel at speed looks good. Map and maf in range. LT fuel trim show -6 to -2 as you drive down the road log flat strech shows +2 to -3. Temp OK timing and all els look in spec. What have I missed?
February 07, 2005
1996 Ford F-250 XL 4.9L No Start, Stall VIN: 1FTEF25Y1T
P0420: Catalyst system effieciency Bank one. Hello everyone, This truck has been giving us fits for the last month or so. Every time we get the truck in the shop off the wrecker or go to look at it seem to be okay. Recently stalled while driving and would not restart. Found no spark condition with no sig...
February 07, 2005
2000 Nissan Sentra GXE 1.8L MIL Lamp on VIN: 3N1CB51D6Y
P0420: Catalyst Efficiency Below Normal. ... tested and found bad MAF, replaced MAF cleared codes. customer returned week later check engine light on. p0420 cat efficiency below threshhold bank 1. Tested Oxygen sensors, ok. Replaced with OE catalytic converter (out of...
February 08, 2005
2000 Chevrolet Suburban 1500 LT 5.3L Excessive Emissions, Misfire, MIL Lamp on VIN: 3GNFK16T3Y
P0420: Catalyst System Low Efficiency (Bank 1). Help!!! I've got this suburban that shows misfires on #1&6. I've checked backpressure and found none. No regulator leaking. I've swapped coils and wires. All injectors drop same pressure. Mis only happens between 2000 and 3000 rpms. The only way i know the...
February 09, 2005
1995 Ford Windstar GL 3.8L No Start VIN: 2FMDA5148S
P0420: Catalyst below threshold. First, thanks for any help offered.. I have an employees 95 3.8 Windstar van here that has an intermittent 'no spark' on initial crank/cold 'ONLY'.. Runs fine the rest of the day with 'no' starting/drivability issues once started.. It may fire off on the firs...
February 09, 2005
1997 Mazda 626 DX 2.0L high idle/hunts cold VIN: 1YVGE22C2V
P0420: Catalyst Efficiency Below Normal (Bank 1). ... warm), idle speed hunts when cold. Sometimes it does this, other times it is fine. At times the vehicle lacks power. Cruise control also does not work, however the cruise did not work before we replaced the engine. No codes in the computer related to this,...
February 09, 2005
2000 Chevrolet Suburban 1500 LT 5.3L Excessive Emissions, Misfire, MIL Lamp on VIN: 3GNFK16T3Y
P0420: Catalyst System Low Efficiency (Bank 1). Help!!! I've got this suburban that shows misfires on #1&6. I've checked backpressure and found none. No regulator leaking. I've swapped coils and wires. All injectors drop same pressure. Mis only happens between 2000 and 3000 rpms. The only way i know the...
February 10, 2005
2000 Lexus LS400 4.0L MIL Lamp on VIN: JT8BH28F8Y
P0420: Catalyst Efficiency Below Normal (Bank 1). ... in my shop with a dtc p0420.(catalyst efficiency below threshold bank 1) about 2 weeks ago this vehicle was at my shop with a dtc p0430 (catalyst efficiency below threshold bank 2)no other codes were stored nor did the customer have any drivability complai...
February 14, 2005
1995 Toyota Tacoma SR5 3.4L MIL Lamp on VIN: 4TAVN73K6S
P0420: catalyst efficiency bank 1. this thing sets a code p0420 about every 500 to 700 miles. freeze frame data shows the b1 s2 02 sensor switching mirroring b1 s1. in my shop with the modis on it every thing is working fine. the b1 s2 switching much slower as designed. thanks john
February 17, 2005
2002 Subaru Forester S 2.5L MIL Lamp on VIN: JF1SF65622
P0420: Catalyst Efficiency Below Normal (Bank 1). I need some help with this Subaru. Cleared code several times and always came back. As per mitchell on demand we checked for exhaust leaks, lowered and checked, visually , both converters, looked fine, check for damage on rear o2 shield wire, disconnected harn...
February 19, 2005
1997 Toyota Camry CE 2.2L MIL Lamp on VIN: 4T1BG22K5V
P0420: Catalyst Efficiency Below Normal (Bank 1). Emission failure. Sets P0420, Bank 1 Cataylst System Effieciency Below Threshold. When looking at O2 sensor voltage, the bank 1 O2 mv will not go below .650 mv. Can induce a vacuum leak and the O2 voltage will go to .900mv but when you ground a spark plug wire...
February 23, 2005
1999 Volkswagen Jetta GLS 2.8L Surge, Stall VIN: 3VWSE29M8X
P0420: Catalyst Inefficiency. ... to me after seeing many repair shops with little work done. The car has been in a collision before and had a poor attempt of an aftermarket radio installed which was corrected with a factory unit. Occasionally the EPC light will come on along with a buck...
February 26, 2005