03 golf po420 code
#1
11-23-2014 | 06:24 AM
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Posts: 4
03 golf po420 code
I replaced the cat on my 03 vw golf 2.0. I drove it about 1700 miles no engine light. I am just now getting a po420 code.. I can't believe the brand new cat is bad. I cleared the sel twice and it came back on after about 60 miles Could it be the o2 sensor? Any help is greatly appreciated. Thanks
#2
11-23-2014 | 06:59 AM
Super Moderator
Joined: Sep 2009
Posts: 2,648
From: Stoke on Trent, England
Welcome to the forum. 
VAG Error Code: 16804
EOBD II Error Code: P0420
Fault Location:
Catalytic Converter System, Bank 1 - Efficiency Below Threshold/Upper Limit Exceeded
Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Leakage in Intake and/or Exhaust System.
Catalyst faulty.
Oxygen Sensor(s) faulty.
Oxygen Sensor(s) Control faulty.
Exhaust tube.
Intake air leaks.
Fuel injectors may be faulty.
Fuel injector leaks.
Spark plugs may be faulty.
Improper ignition timing.
Possible Solutions:
Check Intake and Exhaust System for Leaks.
Check Catalyst.
Check Oxygen Sensor(s).
Check Oxygen Sensor(s) Control.
Perform Oxygen Sensor(s) Aging Check.
Special Notes:
For 1.8T's experiencing this fault code, this thread may be useful: Aftermarket DP/Cat -DTC - Cat efficiency below threshold - Who has this DTC and with DP/Cat
Check the Official Factory Repair Information for any Technical Product Information (TPI)/Technical Service Bulletins (TSBs) that apply to dealer level Engine Controller flash updates for the vehicle in question.
Tech Notes:
As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the Oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.
When is the code detected?:
Three way catalytic converter Bank 1 does not operate properly.
Three way catalyst converter Bank 1 does not have enough oxygen storage capacity.
Description:
The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.
As taken from my https://volkswagenforum.com/forum/ge...oftware-34973/
https://volkswagenforum.com/forum/ne...gnature-34185/
EOBD II Error Code: P0420
Fault Location:
Catalytic Converter System, Bank 1 - Efficiency Below Threshold/Upper Limit Exceeded
Possible Cause:
Malfunction Indicator Lamp (MIL)(K83) active.
Leakage in Intake and/or Exhaust System.
Catalyst faulty.
Oxygen Sensor(s) faulty.
Oxygen Sensor(s) Control faulty.
Exhaust tube.
Intake air leaks.
Fuel injectors may be faulty.
Fuel injector leaks.
Spark plugs may be faulty.
Improper ignition timing.
Possible Solutions:
Check Intake and Exhaust System for Leaks.
Check Catalyst.
Check Oxygen Sensor(s).
Check Oxygen Sensor(s) Control.
Perform Oxygen Sensor(s) Aging Check.
Special Notes:
For 1.8T's experiencing this fault code, this thread may be useful: Aftermarket DP/Cat -DTC - Cat efficiency below threshold - Who has this DTC and with DP/Cat
Check the Official Factory Repair Information for any Technical Product Information (TPI)/Technical Service Bulletins (TSBs) that apply to dealer level Engine Controller flash updates for the vehicle in question.
Tech Notes:
As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the Oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.
When is the code detected?:
Three way catalytic converter Bank 1 does not operate properly.
Three way catalyst converter Bank 1 does not have enough oxygen storage capacity.
Description:
The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2 sensor).
A three way catalyst converter (Manifold) with high oxygen storage capacity will indicate a low switching frequency of heated oxygen sensor 2. As oxygen storage capacity decreases, the heated oxygen sensor 2 switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 and 2 approaches a specified limit value, the three way catalyst malfunction is diagnosed.
As taken from my https://volkswagenforum.com/forum/ge...oftware-34973/
https://volkswagenforum.com/forum/ne...gnature-34185/
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