ODBI had scanners too.. they were just not as "universal" as
the ODBII stuff.

Being that ODB1 systems were more manufacturer proprietary,
aftermarket parts store code scanners weren't widely made.

The dealers had scanners they could hook up to the
pre-'96 vehicles to read ODB1 codes.

I believe Isuzu's unit was called the TECH-1.

1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8