Chart B5 - Anti-Lock Light Circuit: Diode
WARNING: This page is about a different car, the 1988 Buick Riviera and 1988 Buick Reatta. However, it is still accessible from the selected car via links, so may be relevant.
When main relay is enabled, power is provided to EBCM on pins No. 3 and 20 on circuit No. 850. When voltage is present on this circuit, the diode protects EBCM pin No. 27 and ANTI-LOCK light from overvoltage. If diode shorts, code 61 should be set.