If a malfunction is detected during the 1st trip, the first trip DTC is stored in the ECM memory. The MIL light will not light up (two trip detection logic) If the same malfunction is not detected in the second trip, the 1st trip DTC is cleared from ECM memory. If the same malfunction is detected in the 2nd trip, both the 1st trip DTC and 2nd trip DTC are stored in the ECM memory and the MIL lights up.
In other words, the DTC is stored in the ECM memory and the MIL lights up when the same malfunction occurs in two consecutive completed trips.
When the MIL is set freeze frame data is also stored to help in troubleshooting.
If a malfunction is detected during the 1st trip, the first trip DTC is stored in the ECM memory. The MIL light will not light up (two trip detection logic) If the same malfunction is not detected in the second trip, the 1st trip DTC is cleared from ECM memory. If the same malfunction is detected in the 2nd trip, both the 1st trip DTC and 2nd trip DTC are stored in the ECM memory and the MIL lights up.
In other words, the DTC is stored in the ECM memory and the MIL lights up when the same malfunction occurs in two consecutive completed trips.
When the MIL is set freeze frame data is also stored to help in troubleshooting.
So I removed the Alternator and air pump. This helps access wise. I then removed the right intake manifold. I saw that the check valve input (vacuum side) was not connected to anything. (more on that). I removed all of the SAI components and hooked up everything on the bench and vacuum tested with the HF brake bleeder pump. Everything held up. I blew through the shut-off valve and it was closed tight. I applied 12V to the change-over valve with my bench supply and the change-over valve opened with a resounding clunk, and air moved freely. Initially I couldn't find where vacuum line to the check valve was but found it. I think I might have disturbed it when I cleaned the throttle body a month ago, and it slipped off.
1998 Porsche Boxster
Boxster Base
Hybrid Mode
