Question about 2001 Audi A4

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Lots of codes now car wont start

Lots of codes related to the Cat and or O2 sensors P0421 P0431 P0160 P1122 P1140. Yesterday the car wouldn't start. It has has a smell. Not gas, but not far off. Didnt smell like rotten eggs to me, just different. Thoughts?

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The codes would appear to be an Oxygen Sensor
problems & Failed Converters,smell or not

Can't smell after all the expensive rare metals have burned off
from over heating for years

Need to find out why they failed

Check for cylinder misfires & fuel trim issues

Posted on Mar 27, 2014

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Posted on Jan 02, 2017

wolfepac
  • 27 Answers

SOURCE: p0431 code on audi allroad 02

Typcally caused by one of the front oxygen sensors or a bad ground associated with these sensors.Replace both front sensors with direct fit type NOT universal, because there may be a cracked wire and the universal sensor does not contain the complete wire harness. Direct fits, are about $20 more than universal fit type.

The O2 sensors have integrated heating elements that bring them up to the proper operating temperature. Code P0431 indicates that the O2 sensor on your driver side catalytic converter is not reaching the proper operating range. The O2 sensors are usually in the $150 range online.

Posted on Jun 30, 2010

  • 4 Answers

SOURCE: codes p0421 and p0431

Check for air leak on vacuum hoses, and exhaust plus test health of O2 sensors b4 doing the CAT b/c CAT are the most expensive.

Posted on Oct 10, 2010

TDISLine
  • 1874 Answers

SOURCE: why is my audi stops

Check and replace if necessary heated oxygen sensors, wiring, and catalytic converter.

Posted on Oct 31, 2010

  • 3640 Answers

SOURCE: my 96 audi a6 over

ant time you smell rotton eggs its usually the convertor thats bad. get it checked out!

Posted on Aug 27, 2011

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1 Answer

2003 ES. What are the probable causes of DTCs P0421 and P0431?


code p 0421 refers to warm up cat converter bank 1--efficiency below threshold ===causes ---cat converter---wiring---HO2S 2
( heated oxygen sensor)
code p 0431 refers to warm up cat conveter bank 2--efficiency below threshold === causes cat converter --- wiring---HO2S 2
as the same HO2S appears in the cause of the fault I would be inclined to change it first
the HO2sS sensor is the one in the exhaust manifold or before the cat converter
and 2 is in the front bank of a V engine
use the special socket when removing/ replacing these sensors as an incorrect tool is the main reason for wire failures on the sensors

Dec 17, 2015 | 2003 Mazda MPV

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Service engine soon light is on showed p0160 replaced an checked for bad wiring to the mas air sensor still rough idle in gear n now want to shake when it shifts into overdrive it shakes


MOST LIKELY A BAD O2 SENSOR...Potential causes of an P0160 code include: Holes in exhaust near post cat o2 sensor Bad Bank 2, position 2, o2 sensor Wiring problem, melted harness, broken connectors, etc. Bad PCM

Apr 16, 2015 | 1996 Chevrolet Suburban

1 Answer

P0421 code bank 1 warm-up efficiency below limit


P0421 code is that the cat. converter is below efficiency. 99 per cent o the time the cat. needs to be changed. but if you have a scan tool watch both bank 1 O2 sensor 1 and bank 1 sensor 2.
cold they should be almost the smae but when its at operating temp, and running down the road at crusie speed the frt o2 should switch rapidly between .150 mv. and .850 mv. and the rear o2 should read about .600 mv. if they read the same the cat is ng and will have to be replaced.

Oct 28, 2013 | 2001 Mazda Millenia

1 Answer

P0431


Well code 431 means the computer does not think the catalytic converter is working correctly. The engine computer uses data from the O2 sensors to monitor the cat.
The actual problem could be the cat, one of the O2 sensors, a fuel problem, or other things. The O2 sensors would need to be watched with a scanner to find the issue.

Jul 17, 2013 | 2002 Mitsubishi Diamante

2 Answers

SERVICE ENGINE SOON LIGHT CAME ON READS CODE P0431 AND P0421


Converter is not working as efficiently in Bank 1 and Bank 2 (two codes)...

P0421 - Warm Up Catalyst Efficiency Below Threshold (Bank 1)
Basically this means that the oxygen sensor downstream of the catalytic converter on bank 1 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms: You will likely not notice any drivability problems, although there may be symptoms. The code may be more likely to occur after the engine has had numerous cold starts in the past 1-2 days.

Causes: A code P0421 may mean that one or more of the following has happened:
The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
A sparkplug is fouled up

Possible Solutions:
Measure the voltage at the oxygen sensor on Bank 1 (the rear sensor, or the sensor after the converter). In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.

P0431 - Warm Up Catalyst Efficiency Below Threshold (Bank 2)
Basically this means that the oxygen sensor downstream of the catalytic converter on bank 2 is detecting that the converter is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.

Symptoms: You will likely not notice any drivability problems, although there may be symptoms such as a rough/hard idle when cold.

Causes: A code P0431 may mean that one or more of the following has happened:
The catalytic converter is no longer functioning properly
An oxygen sensor is not reading (functioning) properly
There is an exhaust leak

Possible Solutions:
Inspect for exhaust leaks. Next step is to measure the voltage at the oxygen sensor on Bank 2. In fact, it would be a good idea to test each oxygen O2 sensor while you're at it.

One thing to note is that many vehicle manufacturers offer a longer warranty on emissions-related parts. So if you have a newer car but it's out of it's bumper-to-bumper warranty, there still may be warranty on this type of problem. Many manufacturers give a five year, unlimited mileage warranty on these items. It's worth checking into.


Hope this helps.

May 05, 2011 | 2004 Mitsubishi Endeavor

1 Answer

03 santa fe code p0421 for warm up catalyst below bank 1is it converter sensors whats bank 1 converter location compared to bank 2 is there 2 banks or converters would it be upstream or downstream if it...


If the engine is a V6 (2.7 or 3.5 lit), bank 1 is next to the firewall (right hand) when facing the back of the engine.
If the engine is a 4 cly (I4), there is only one bank and is designated Bank 1 (exhaust manifold).

The catalyst to which the code refers is the UPSTREAM, and there is only ONE upstream cat for any bank.

Clue: Two upstream O2 sensor and two downstream O2 sensors - one before the CAT and one after the CAT. the downstream O2 sensors are identical to their upstream sisters. The only reason for the DOWNstream sensor is to monitor the CAT efficiency (threshold).

The catalyst on either bank is essentially the exhaust manifold which houses the CAT... it is the only CAT to which the code P0421 applies.

Hope that helped

Feb 06, 2011 | Hyundai Santa Fe Cars & Trucks

1 Answer

2001 mitsubishi galant with a P0421 code whut to do


this code relates to catalytic converter efficiency, could be a bad o2 sensor, bad cat , prob gonna need a mechanic to diagnose, if you do decide to replace o2 sensor you want to change the one behind cat, tghis one monitors cat function

May 18, 2010 | 2001 Mitsubishi Galant

3 Answers

Spinning My Wheels!! ---- P0421 Code Mitsubishi Galant


I have the same vehicle, same code P0421, changed the BOTH O2 sensors and the check engine light was still on, took it to my fathers garage and checked the Catalytic Converter, and it was ok later I found out that P0421 means that the vehicle doesn't have the proper mixture of gas and air (running richer) so I changed the MAX air flow sensor and wala the code went away.

Mar 30, 2009 | 2003 Mitsubishi Galant

1 Answer

Codes p0421 and p0431


Check for air leak on vacuum hoses, and exhaust plus test health of O2 sensors b4 doing the CAT b/c CAT are the most expensive.

Nov 26, 2008 | 2003 Audi A6

1 Answer

Failure code P0431


The Bank 2 after-cat O2 sensor is detecting that the cat is not working as efficiently as it should. It could be a bad catalytic converter, bad O2 sensor, or an exhaust leak.

Sep 19, 2008 | Mitsubishi Montero Sport Cars & Trucks

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