Code 31 - No Reference Signal

NOTE: To check ignition system components, see IGNITION SYSTEM in SYSTEM & COMPONENT TESTING - CARBURETED article.

NOTE: Test numbers refer to test numbers on diagnostic chart.

This step checks for poor connection at ignition coil connectors as cause of no reference pulse.
This step determines if reference pulse is being sent to ECM.

Fig 1: Chart 31 - Schematic

Courtesy of ISUZU MOTOR CO.

Fig 2: Chart 31 - Diagnostic Flowchart

Courtesy of ISUZU MOTOR CO.