Description of On-Board Diagnostics

DESCRIPTION OF A140E DIAGNOSIS SYSTEM




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

NOTE: Warning and diagnostic codes can be read only when the overdrive switch is ON. If OFF, the O/D OFF indicator 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 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 diagnostic code can be read by the number of blinks of the O/D OFF indicator when terminals ECT and E(1) are short-circuited.

NOTE:
- If diagnostic code Nos. 42, 61, 62 or 63 are output, the O/D OFF indicator light will begin to blink immediately to warn the driver. However, an impact or shock may cause the blinking to stop; but the code will still be retained in the ECT ECU memory until canceled out.
- There is no warning for diagnostic code No.64.
- In the event of a simultaneous malfunction of both No.1 and No.2 speed sensors, no diagnostic code will appear and the fail-safe system will not function. However, when driving in the D range, the transaxle will not up-shift from first gear, regardless of the vehicle speed.

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 service connector (diagnosis).




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 (malfunction) code is retained in memory by the CPU 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 EFI (15A) or disconnect the ECT computer connector to cancel out the diagnostic (malfunction) 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 k ohm/V.