ELECTRONIC CONTROL SYSTEM IDENTIFICATION
See ELECTRONIC CONTROL SYSTEM IDENTIFICATION table and (Scheme 70) - (Scheme 73).
| Transmission | EGS System |
|---|---|
| 4HP 22/4HP 24 (Early, Approximately 1987-1988) | 1.XX |
| 4HP 22/4HP 24 (Later, Aproximately 1988-1994) | 1.XX |
ELECTRONIC CONTROL SYSTEM IDENTIFICATION
Scheme 70
Scheme 71
Scheme 72
Scheme 73
FUNCTIONAL DESCRIPTION
The A300 control unit monitors engine speed (terminal No. 21), injection signal (terminal No. 11), throttle position (terminal No. 7), road speed (terminal No. 8), kick-down signal (terminal No. 2), gear selector position (terminals No. 30, 28, 29, and 18), and program switch signal (terminals No. 14, 15, and 4). The A300 control unit electronic processing circuit compares this information with the A300 control unit program data. The A300 control unit then selects the correct gear and clutch engagement rate by controlling the shift valve solenoids and the hydraulic pressure regulator. The A300 control unit retards engine time during shifts by grounding terminal 24 for one second when shifting gears. This provides for a smoother shift.
The A4 check control module displays TRANSMISSION if a problem with the control system occurs. If a fault is detected, the transmission emergency problem turns on. Voltage to the Y300 transmission (terminal 1) is turned OFF and the vehicle can be driven only in third and reverse gears. NEUTRAL and PARK retain their functions.
CIRCUIT OPERATION
The Electronic Transmission Control System (AEGS) contains 3 transmission modes to provide smooth refined shifts through the interaction of transmission and engine electronics. Transmission operates the selected gear and does not shift up or down automatically. The Electronic Transmission Control System (AEGS) has the following components
- Automatic Transmission Range Switch.
- Check Control Module.
- Electronic Transmission Control Unit (AEGS).
- Instrument Cluster.
- Kick-Down Prevent Relay.
- Motronic Control Unit.
- Program Switch.
- Idle Switch.
- Transmission.
- Transmission Kick-Down Switch.
By operating program switch, driver can select 3 transmission modes: ECONOMY, MANUAL, and SPORT. When E (ECONOMY) is selected, terminal No. 14 of the AEGS is momentarily grounded through the switch to terminal No. 6 of AEGS control unit. When S (SPORT) is selected, terminal No. 4 of control unit is momentarily grounded through the switch to terminal No. 6 of the control unit. Fourth gear is not selected and first, second, and third gears are kept engaged up to a higher engine speed. When ignition switch is turned off, then to run, control unit automatically selects E (ECONOMY).
CONNECTOR IDENTIFICATION
For connector identification (Scheme 74)- (Scheme 77).
