Displaying & Reading Trouble Codes

Overdrive Light:

PURPOSE
A self-diagnosis function is built into the electrical control system. Warning is indicated by the overdrive OFF indicator. If a malfunction occurs within the speed sensors or solenoids, the overdrive OFF indicator light will blink to warn the driver. A malfunction in the lock-up solenoid circuit will produce a fault code, but the warning indicator will not flash.

HINT: Warning and diagnostic codes can be read only when the overdrive switch is ON. When the overdrive switch is in the off position, the O/D light is illuminated and will not flash.

OPERATION
The diagnostic code can be read by the number of blinks of the overdrive OFF indicator when terminals TE1 and E1 are short-circuited.

The throttle position sensor and brake signals do not generate fault codes but inspection can be made by checking the voltage at terminal Tt of the check connector.

The signals to each gear can be checked by measuring the voltage at terminal Tt of the check connector while driving.

The diagnostic (malfunction) code is retained in memory by the ECU and is not canceled out when the engine is turned off. After repair, it is necessary to turn the ignition switch off and remove the EFI fuse (15 A) or disconnect the ENGINE and ECT ECU connector to cancel out the diagnostic (malfunction) code.