The BAFX scan tool, a powerful diagnostic device, allows car enthusiasts and professionals alike to delve into the intricate workings of their vehicles. By accessing specific test IDs and modes, users can unlock a treasure trove of information, enabling them to pinpoint issues with precision. This article explores the capabilities of the BAFX scan tool, specifically focusing on Mode $31 and its potential for uncovering hidden problems.
Mode $31, often referred to as the “functional test” mode, provides a gateway to perform specific tests on various vehicle systems. Through experimentation with a BAFX scan tool and wOBD software, it was discovered that certain test IDs within Mode $31 elicit unique responses from the vehicle’s Engine Control Module (ECM). For instance, Test ID $3181, when issued with the engine off (KOEO – Key On Engine Off), triggers the “check engine” light and activates various relays, including the fuel pump. When the engine is running (KOER – Key On Engine Running), the same test ID ($3181) returns a “00 00 22” response, indicating the test is unavailable or already in progress. This suggests that $3181 is specifically designed for KOEO diagnostics.
Further investigation revealed that Test ID $3182, when executed with the engine running (KOER), initiates changes in RPM and cylinder deactivation. This behavior points towards a KOER test aimed at assessing engine performance under load. Interestingly, all Mode $31 requests consistently return a “7F” prefix, typically associated with an invalid request. However, subsequent data indicates successful test initiation or specific status codes like “00 00 00” (test started) or “00 00 22” (test unavailable). This nuance underscores the importance of understanding the specific response codes for accurate interpretation. A “00 00 12” response, however, likely signifies an invalid test ID.
While the BAFX scan tool excels in accessing functional tests, challenges remain in retrieving continuous Diagnostic Trouble Codes (DTCs). Attempts to access PID $02 for both the OBDII and Powertrain Control Module (PCM) modules yielded no results, indicated by “0100” or “220100” responses. Similarly, using OBDII DTC Mode $03 returned no data, suggesting no OBDII DTCs were set. Further research is needed to determine how to access non-OBDII DTCs through the PCM using Mode $22.
The ability to execute these tests and interpret their results is crucial for diagnosing intermittent issues, such as a suspected cylinder misfire. In this specific case, a noticeable misfire occurring every 2-4 seconds at around 2100 RPM, accompanied by audible and physical vibrations, necessitates a deeper diagnostic approach. Accessing non-MIL (Malfunction Indicator Lamp) or non-OBDII DTCs through the BAFX scan tool could provide invaluable insights into pinpointing the root cause of this intermittent problem. By leveraging the advanced capabilities of the BAFX scan tool, mechanics and car owners can unlock a deeper understanding of their vehicle’s health, enabling them to address issues efficiently and effectively.
