Conditions for Setting the DTC

WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

A DTC B1428 sets when the BCM detects a short to ground in the IGN 1 relay control feed circuit when It is trying to energize the IGN 1 relay.
A DTC B1428 sets when the BCM detects an open in the IGN 1 relay control feed circuit when It is trying to energize the IGN 1 relay.
The conditions above must be present for more than 0.3 seconds.