When servicing catalytic converters, it’s important to have a basic understanding of how they operate.
Recently, the shop had a 2002 Lexus SC 430 in for a check engine light with evap codes P0440 – evap malfunction; P0441 – evap incorrect purge flow; and P0446 – evap vent control malfunction.
Andrew Markel discusses the development of the EVAP system as emissions standards changed over time.
We recently had a 2002 Elantra GLS in the shop with assorted issues, so let’s take a look at this job since it’s a good example of some common problems we see.
Oxygen sensors are used to monitor the engine’s air/fuel mixture so the powertrain control module (PCM) can make adjustments that optimize fuel economy, emissions and performance.
The engine computer needs to know what the fuel mixture is with a high degree of precision so it can optimize fuel economy as well as emissions. If the information received by the powertrain control module (PCM) from its sensors is not accurate, it may command too much fuel or not enough.
If the MIL is on, or even commanded on, with no current code related to emissions, it can be cause for a failure. The vehicle will still be scanned for codes and readiness flags will be checked, but an MIL on with the engine running will almost always spell “failure.”
Take a look at the fuel injection system and driveability issues on Hyundai’s line of vehicles.
Use your gas analyzer as a tool cut you diagnostic time, sell more fuel injection service, and help you make more money.
Before a technician replaces a converter, they need to address the possible reasons for it failing in the first place.