WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL S ECTION 1 — GENERAL DESCRIPTION Copyright © 2001 General Motors Corp. 1–1. TRANSMISSION The World Transmission Electronic Controls (WTEC III) system features closed-loop clutch control to provide superior shift quality over a wide range of operating conditions. The 3000MH, MD 3000, 4000MH, HD 4000, and B Series configurations can be programmed to have up to six forward ranges, neutral, and one reverse range. The MD 3070 and HD 4070/4076 have up to seven forward ranges and one reverse range. Figure 1–1 is a block diagram of the basic system inputs and outputs.
SHIFT SELECTOR RANGE AND MODE SWITCH DISPLAY SPEED SENSORS OIL LEVEL SENSOR THROTTLE POSITION SENSOR SOLENOIDS ECU RETARDER MODULATION C3 PRESSURE SWITCH VEHICLE/ENGINE TEMPERATURE SENSOR COMMUNICATION LINKS (SUMP/RETARDER) VIM INPUTS OUTPUTS V03469 Figure 1–1. Electronic Control Unit Block Diagram Figure 1–2 shows WTEC III electronic control components. WTEC III Electronic Controls consist of the following elements:
• Remote 12/24V Max Feature Sealed Electronic Control Unit (ECU) • Remote Pushbutton or Lever Shift Selector • Optional Secondary Shift Selector • Throttle Position Sensor (TPS) (or electronic engine throttle data or PWM signal) • Engine, Turbine, and Output Speed Sensors • Control Module (Electro-Hydraulic Valve Body) • Wiring Harnesses • Vehicle Interface Module (VIM) • Autodetect Feature • TransID Feature • Optional Retarder Controls • Optional Engine Coolant Temperature Input NOTE:
• All external harnesses are OEM supplied • Some OEMs may supply their own shift selector • The VIM is an OEM option SHIFT SELECTOR RANGE AND MODE SWITCH DISPLAY SPEED SENSORS OIL LEVEL SENSOR THROTTLE POSITION SENSOR SOLENOIDS ECU RETARDER MODULATION C3 PRESSURE SWITCH VEHICLE/ENGINE TEMPERATURE SENSOR COMMUNICATION LINKS (SUMP/RETARDER) VIM INPUTS OUTPUTS V03469 Figure 1–1. Electronic Control Unit Block Diagram Figure 1–2 shows WTEC III electronic control components. WTEC III Electronic Controls consist of the following elements:
• Remote 12/24V Max Feature Sealed Electronic Control Unit (ECU) • Remote Pushbutton or Lever Shift Selector • Optional Secondary Shift Selector • Throttle Position Sensor (TPS) (or electronic engine throttle data or PWM signal) • Engine, Turbine, and Output Speed Sensors • Control Module (Electro-Hydraulic Valve Body) • Wiring Harnesses • Vehicle Interface Module (VIM) • Autodetect Feature • TransID Feature • Optional Retarder Controls • Optional Engine Coolant Temperature Input NOTE: • All external harnesses are OEM supplied • Some OEMs may supply their own shift selector • The VIM is an OEM option