Description of On-Board Diagnostics

DESCRIPTION




1. A self-diagnosis function is built into the electrical control system. Warning is indicated by the "O/D OFF" indicator light.

NOTE: Warning and diagnostic codes can be read only when the overdrive switch is ON. If OFF, the O/D OFF light is lit continuously and will not blink.

a. If a malfunction occurs within the speed sensors (No.1 or 2) or solenoids (No.1 or 2), the overdrive OFF light will blink to warn the driver.
However, there will be no warning of a malfunction with lock-up solenoid.




b. The diagnostic code can be read by the number of blinks of the O/D OFF indicator light when terminals ECT and E1 are short-circuited.




If the vehicle is equipped with a super monitor display, the diagnostic code is read by operation of same.

c. The throttle position sensor or brake signal are not indicated, but inspection can be made by checking the voltage at terminal ECT of the diagnostic service connector.
d. The signals to each gear can be checked by measuring the voltage at terminal ECT of the service connector while driving.

2. The diagnostic code (trouble code) is retained in memory by the CPU (of ECT ECU) and due to back-up voltage, is not canceled out when the engine is turned off. Consequently, after repair, it is necessary to turn the ignition switch off and remove the fuse DOME (7.5A) or disconnect the ECT ECU connector to cancel out the diagnostic (trouble) code.

NOTE:
- Low battery voltage will cause faulty operation of the diagnosis system. Therefore, always check the battery first.
- Use a voltmeter and ohmmeter that have an impedance of at least 10 kOhms/V.