Scanmaster 2.0 could get stuck in pulsewidth and spark advance mode if a noise pulse was received at just the right time.
2.1 doesn't do this.
For pulsewidth and spark advance , and maintaining 'slow' data stream with malfunction codes, get datastream "Z"
For high speed data (with PL and SP) get datastream Y for Scanmaster 2.0, or W for Scanmaster 2.1. (no malfunction codes in high speed data)
Bob