As with the catalyst monitor, a problem won’t set a DTC until the same fault has occurred twice under nearly similar conditions. The EVAP monitor also has a long list of requirements that must be met before it will run, things like a certain number of hours of "cold soak" with the engine off before it will run a pressure or vacuum test to check for fuel vapor leaks. The EVAP monitor checks for vapor leaks in the fuel tank and EVAP canister plumbing. The story is similar for the EVAP monitor. Under these conditions, the catalyst monitor will usually run within 15 minutes or less. There also must be no DTCs present for the oxygen sensors. As a rule, the engine must be hot (170° to 230° F), the PCM must be operating in closed loop and the vehicle must be cruising at part throttle from 25 to 35 mph. The catalyst monitor requires specific driving conditions before it will run, so it make take several days or even a week or more of driving before all the conditions are just right to run the monitor. Each scan tool manufacturer labels these functions somewhat differently, but all more or less allow you to access much of this information. If you want to clear codes, you choose "Clear Codes" on the scan tool menu.
So if you want to check for any DTCs, you choose "Check DTCs" on the scan tool menu. They are usually labeled by their function rather than mode number. When you plug in a scan tool, you don’t necessarily see all of these things listed as operating modes. Mode $08 – Bidirectional communication (onboard tests) Mode 09 – Vehicle VIN, PCM calibration, etc. Mode $06 – Non-continuous monitors (EVAP, catalyst, EGR, etc.) Mode $04 – Clear codes and freeze-frame data Mode $02 – Freeze-frame data (if DTCs are present) Mode $01 – Data stream (sensor readings and switch status) So what kind of information did SAE think technicians should be able to access with a scan tool? All of the following:
0 kommentar(er)
