Transmission Control Systems: Description and Operation

DIAGNOSIS SYSTEM DESCRIPTION








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

HINT: Warning and DTC can be read only when the O/D main switch is ON. If OFF, the O/D OFF light is lit continuously and will not blink.

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





(b) The DTC can be read by the number of blinks of the O/D OFF indicator light when terminals TEl and El are connected with SST.

(c) The throttle position sensor or brake signal are not indicated, but inspection can be made by checking the voltage at terminal TT of the DLC1.





(d) The signals to each gear can be checked by measuring the voltage at terminal TT of the DLC1 while driving.





2. The DTC is retained in memory by the ECM 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 EFI fuse (15A) or disconnect the ECM connector to cancel out the DTC.

HINT:
- Low battery positive 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 k Ohms.