Having problems with your 2003 Chevrolet S-10 ?

I have a 2001 chevy S-10 2.2 liter. What does Code P0420 mean??

\015 I have a 2001 chevy S-10 and its time to get emissions again and the service engine light is on ofcourse!! Im getting Code P0420 just wondering if anyone has had this issue before and may be of some assistance as to what is causing this??\015 Posted / edited by AnonymousUser on : 19-11-2018

Answers :

Here are a number of things that could be causing this p0420 catalyst efficiency code. The most common thing is the catalytic converter itself is no longer functioning properly. \012
\012The other likely thing is the rear O2 (oxygen) sensor is no longer working properly. Other things could include exhaust leaks, damaged exhaust pipes, damaged O2 sensor wiring/connectors, plugged catalytic converter, etc.\012\012
\012The easiest thing to do first is a visual check of things. Visually inspect the exhaust system for leaks, check the catalytic converter for dents, holes, severe discoloration, and check for a rattle inside. If any of those syptoms are there, the converter likely needs replacement. \012
\012Then, visually inspect the downstream O2 sensor (behind the converter). Check for broken wires, obvious faults, etc. If all that checks out, you'll want to check the operation of the O2 sensor. To do that, you'll need access to a scan tool or oscilliscope. Check that the waveform is pretty steady. If the reading fluctuates then the sensor is likely bad and will need to be replaced.\012
\012Try this, turn the ignition key to the on position, (engine not running) and pull the fuse to your ECM for 30 seconds and then re-install it. Once re-installed, start the engine and let idle for 1 min and then go for a test drive. \012
\012If the engine stalls, let it. The ECM is relearning the sensors and engine, just restart it and after 1 min when the RPM drops. God for a test drive and see if the service engine light comes back on and re-scan for the DTC codes and address the issues indicated by the DTC code. \012
\012Thank you for using fixya and good luck.
Repair Help & Product Troubleshooting for 2003 Chevrolet S-10

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