Question about Hyundai Accent
I am Sorry to hear regarding the Problem.
check for exhaust leak between oxygen sensor 1 and 2. if no leak.Looks like it points to pre catalyst not doing
its job.You need to replace the Sensor.
P0421 - WARM UP CATALYST LOW EFFICIENCY BANK 1
Catalytic converter efficiency is measured by how well the converter can store and release oxygen needed to convert CO, HC and NOx gases to C02 and water. Under normal operating conditions except heavy acceleration, cold engine temperatures and extended decelerations, the heated oxygen sensor (HO2S) bank 1 sensor 2 voltage should remain relatively steady between 500 mV and 800 mV. This steady reading of the HO2S bank 1 sensor 2 indicates a correctly functioning pre-catalytic converter as the air/fuel ratio changes slightly around 14.7 to 1. If the pre-converter is storing and releasing oxygen correctly. the HO2S bank 1 sensor 2 should hold its voltage value for a certain length of time as the air/fuel ratio increases or decreases. Under relatively steady cruise. the ECM will run a test which records the voltage amplitude values of the HO2S bank 1 sensor 2 as an oscillating air/fuel ratio is introduced. The ECM will then compare the amplitudes it obtained to modeled values of a new-failed catalyst. The closer the actual amplitudes of the HO2S bank 1 sensor 2 are to the modeled new-failed catalyst values. the more inefficient the pre-converter is becoming. DTC P0421 sets when the ECM has determined that the bank 1 pre-catalytic converter is no longer efficient.
Let me know,if needed further assistance.
Hope i helped you.
Thanks for using ' Fixya ' and have a nice day!!
Posted on May 30, 2010
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Sep 04, 2016 | Hyundai Motor 1998 Accent
Apr 30, 2013 | 2003 Mazda Mazda6
Nov 07, 2011 | 2001 Hyundai Accent
Feb 06, 2011 | Hyundai Motor 1998 Accent
May 08, 2010 | 1998 Volkswagen Beetle
Feb 22, 2010 | 2001 Hyundai Accent
Oct 01, 2009 | 1996 Hyundai Accent
Feb 26, 2009 | Hyundai Motor 1998 Accent
Jan 05, 2009 | 1999 Hyundai Accent
33 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: