Test Procedure

WARNING: This page is about a different car, the 1989 Cadillac Allante. However, it is still accessible from the selected car via links, so may be relevant.

This step checks for intermittent operating conditions.
This step checks to see if the open is in circuits 800F or 800D.
If there is an open in circuits 800F or 800D, this step finds which side of the ALDL it is on.
This step checks for an open in circuit 800E.

Fig 1: DTC B334: Loss Of ECM Data Flow Chart

Courtesy of GENERAL MOTORS CORP.