Section 7 (Starting System & Charging System (WRX-STI)): Generator: Inspection: Diode

WARNING: This page is about a different car, the 2013 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: There is the possibility of damaging the diodes if a mega-tester (used to measure high voltages) or a similar measuring instrument is used. Never use a mega tester or equivalent for this test.

Check for continuity between the diode lead and positive side heat sink. If resistance is 1 Ω or more only in the direction from the diode lead to the heat sink, replace the rectifier.

Fig 1: Checking Continuity Between Diode Lead And Positive Side Heat Sink
Courtesy of SUBARU OF AMERICA, INC.
Check for continuity between the negative side heat sink and diode lead. If resistance is 1 Ω or more only in the direction from the heat sink to the diode lead, replace the rectifier.

Fig 2: Checking Continuity Between Negative Side Heat Sink And Diode Lead
Courtesy of SUBARU OF AMERICA, INC.