Sep 7, 2009 · Code 420 - Catalyst Inefficiency. CarCrazyRDM. 09-07-2009, 07:13 PM. Is there a way to determine for sure ...

Apr 4, 2007 · I have a 2002 century 3.1 L That is giving me code P0420.I had to replace the lower intake gasket before the code ever showed up.I also replaced the cat. converter because it was plugged do to the coolant leaking into the intake for sometime.After the cat. was replaced this code showed up.I replaced the ignition module and both O2's.I've only gotten it to go out long enough to pass emissions ...

Apr 5, 2008 · OBD II , Code 420 (Catylist efficiency below threshold, bank one). Is this a catylitic converter problem, or a Oxygen Sensor problem, or something else??? Has anyone experienced this before??? Thanks in advance for any help you may offer.

Jun 4, 2006 · If misfire code(s) is present, isolate cylinder and repair as necessary. Check HO2S Monitor DTCs If DTCs P0136, P0138, P0140, P0141, P0156, P0158, P0160, or P0161 were present in step 1), service as necessary before continuing.

Jun 27, 2005 · I cleaned the EGR passage way and replaced the coil because there was no spark on 2 even though there was spark on 6. Doing that solved those problems and the check engine light stayed off for a few days. It came back on and now I have a code 420 for Catalyst System Efficiency Below Threshold (Bank 1).

May 19, 2007 · Here is a little info on 420 codes. DTC P0420, P0421, and P0430 & P0431: Check Possible Cause Of Misfire DTC P0420 and P0421 indicate bank one catalyst system efficiency is minimum requirement. DTC P0430 and P0430 indicate bank 2-catalyst system efficiency is minimum requirement.

code 420 on 96 2.4L; Install XM Mini Reciever; Help, Locating Fuel Filter 96 Tacoma 4cyl; Ticking/Clicking noise under the hood; Brake Lights; Gear shift indicator light; Tacomas rust easy? Getting warm to Hot; car still pulls to the right after alginment; Tail Light Removal; keyless remote entry programming; Looking for O2 help; Timing belt ...

P1404, 0131, and 0137 Code Set; Occasional miss, comes and goes 94 3.8; Battery Check Light; Shuddering between 1st and 2nd; Code 420 Converter Efficiency below threshold; rear a/c blows red hot; jay2bears; 2000 olds silhouette wipers; Gas Cap Code; Steering Failure... dire; 99 Olds Silhouette firing order; P0141 Code; 1990 silohette steering ...

Nov 2, 2005 · CRUCC 2.0 - Car Radio Universal Code Calculator ©2.0 ... BLAUPUNKT BLAUPUNKT 420 92 057 960 BP8382 ...

May 3, 2006 · I have a 99 Cougar with 4 codes showing. P0420- Bank 1 Catalyst Efficiency Below Threshold P1151- Manufacturer Control Fuel Air Metering