Description of On-Board Diagnostics

Input/Output Signal Of A/T Control Unit:

PURPOSE
The self-diagnostic system is designed to help technicians fix cars faster.
OPERATION
This is done by having the Automatic Transmission Control Unit monitor certain input/outputs and store a trouble code if the Automatic Transmission Control Unit detects a problem.
Stored diagnostic trouble codes can be accessed by using the on-board self-diagnostic trouble code information display.

CONSULT OPERATION
The CONSULT Scantool electrically displays shift timing and lock-up timing (that is, operation timing of each solenoid). When a noticeable time difference occurs between shift timing which is manifested by shift shock and the CONSULT display, mechanical parts (except solenoids, sensors, ect.) are considered to be malfunctioning. Check mechanical parts using applicable diagnostic procedures.

Shift schedule (which implies gear position) displayed on CONSULT and that indicated in "Severe Service Maintenance Schedule" may differ slightly. This occurs because of the following reasons:
^ Actual shift schedule has more or less tolerance or allowance.
^ Shift schedule indicated in Automatic Transmission refers to the point where shifts start, and gear position displayed on CONSULT indicates the point where shifts are completed.
Shift solenoid valve "A" or "B" is displayed on CONSULT at the start of shifting while gear position is displayed upon completion of shifting (which is computed by A/T control unit).
Additional CONSULT information can be found in the Operation Manual supplied with the CONSULT unit.