Description of On-Board Diagnostics

Description

The ELC-4A/T transaxle is a conventional transaxle in that it uses hydraulically applied clutches to shift a planetary geartrain. However, the electronic control system replaces many of the mechanical and hydraulic components used in conventional transaxles.

The ELC-4A/T transaxle is a fully adaptive electronic control system. This system performs its functions based on continuous real-time sensor feedback information. The control system automatically adapts to changes in engine performance of friction element variations to provide consistent shift quality. The control system ensures that clutch operation during upshifting and downshifting is more responsive without increased harshness.

Fail-Safe Mode

The ELC-4A/T controller continuously checks for electrical and internal transaxle problems. When a problem is sensed, the controller stores a fault code. Some of these fault codes, if repeated four times, can generate a fail-safe code. If a fail-safe code is set electrical power is taken away from the shift control solenoids, the damper clutch control solenoid, and the kickdown servo switch. When this happens, the only transaxle ranges that will function are:

- Neutral and Park

- Reverse

- Second or Third Gear

No upshifts or downshifts are allowed. The position of the manual valve alone dictates which range the transaxle is in. Although engine performance is seriously degraded while in this mode, it allows the owner to drive the vehicle in for service.