Displaying & Reading Trouble Codes

PURPOSE
A self-diagnosis function is built into the electrical control system. Warning is indicated by the "O/D OFF" indicator light. Warning and diagnostic codes can be read only when the overdrive switch is ON. If OFF, the overdrive OFF indicator light is lit continuously and will not blink.

OPERATION
If a malfunction occurs within the speed sensors (No. 1 or 2) or solenoids (No. 1 or 2), the "O/D OFF" light will blink to warn the driver. A malfunction with the lock-up solenoid will set a code but will not cause the indicator to flash.

The diagnostic code can be read by the number of blinks of the overdrive OFF indicator light when connect TDCL terminals, TE1 and E1 or CHECK CONNECTOR terminals TE1 and E1.

The throttle position sensor or brake signal will not set codes, but inspection can be made by checking the voltage at TDCL terminal Tt.

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

The diagnostic code (trouble code) is retained in memory by the ECU (of Engine & ECT ECU). After repair it is necessary to turn the ignition switch off and remove the EFI fuse (15A) or disconnect the Engine & ECT ECU connector to cancel out the diagnostic (trouble) code.

NOTE:
^ Low battery voltage will cause faulty operation of the diagnosis system.
^ Use a voltmeter and ohmmeter that have an impedance of at least 10 K Ohms.