P0420 Diagnostic Trouble Code Discussion for August 2007
Catalyst Efficiency Below Normal (Bank 1)
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| Help Request | Posted | |
| 2002 Buick Century Custom 3.1L MIL Lamp on P0420: Catalyst System Low Efficiency. Vehicle came in with P0420 Cat effciency code. Checked o2's and found these strange readings. At idle pre cat o2 working fine. Post cat o2 sitting @ .400mv. LTFT -4%. Then when revved to 2500 in park... LTFT goes to -14/-16%. Pre cat o2 still toggles great. Po... |
August 09, 2007 | |
| 2003 Audi A4 1.8L MIL Lamp on VIN: WAUJC68E63 P0420: cat not efficient cyl.1. This Audi came in with the above codes. Thought maybe the low voltage code may be a sign of what caused the misfire codes, so checked power at term#3 of control moduel, and grounds at Terms# 1$2. All check ok, grounds are clean and tight under the abs pump. Al... |
August 13, 2007 | |
| 2001 Nissan Pathfinder LE 3.5L Misfire, MIL Lamp on, p1320 VIN: JN8DR07Y41 P0420: Catalyst Efficiency Below Normal (Bank 1). ... concern of runninh rough and light comming on intermitantly. at that time we found the 2 pending codes. p0420b p1320. we replaced the b1 cat and returned vehicl to customer. car came back with hard failures p0302 #2 missfire and p1320 primery ignition sign... |
August 17, 2007 | |
| 1997 GMC Safari SLE 4.3L MIL Lamp on VIN: 1GKDM19W8V P0420: Catalyst System Low Efficiency (Bank 1). ... the freeway. Pulled over and restarted with a high idle. Drove it home and the next day it started and stalled three times. After that it ran perfectly fine. A couple of days later the check engine light comes on. (I'm assuming it had an IAC problem) They ... |
August 20, 2007 | |
| 1998 Honda Accord LX 2.3L MIL Lamp on VIN: 1HGCG5644W P0420: Catalyst Efficiency Below Threshold (Bank 1). ... P0420 Cat. effic. for the last 2 years and I am out of ideas and need help.It started 8/23/05 with the P0420 code & I cleared the code because every thing looked good with the scan tool. Told them to let me know if it came back on, that was at 119471 M... |
August 24, 2007 | |
| 1998 Honda Accord LX 2.3L MIL Lamp on VIN: 1HGCG5644W P0420: Catalyst Efficiency Below Threshold (Bank 1). ... P0420 Cat. effic. for the last 2 years and I am out of ideas and need help.It started 8/23/05 with the P0420 code & I cleared the code because every thing looked good with the scan tool. Told them to let me know if it came back on, that was at 119471 M... |
August 27, 2007 | |
| 1999 Mazda Protege DX 1.6L no mil light VIN: JM1BJ2226X P0420: Catalyst Efficiency Below Normal (Bank 1). I replace pcm with a mazda reman. and the same thing happens. 02 sensor look like they mimick eachother and have a new cat. Why is a code set but not turning on check engine light and why is no pending codes not setting the code this is really baffling me. ple... |
August 30, 2007 | |
| 1999 Mazda Protege DX 1.6L no mil light VIN: JM1BJ2226X P0420: Catalyst Efficiency Below Normal (Bank 1). I replace pcm with a mazda reman. and the same thing happens. 02 sensor look like they mimick eachother and have a new cat. Why is a code set but not turning on check engine light and why is no pending codes not setting the code this is really baffling me. ple... |
August 31, 2007 |
