Chapter 21 Chassis System Electronics 415
Copyright by Goodheart-Willcox Co., Inc.
Figure 21-29. Transaxle ECM controls the operation of automatic transmissions and transaxles. Solenoids in a transmission redi-
rect fl uid pressure to engage each gear, lock up the torque converter for better gas mileage, and adjust transmission operation with
vehicle speed, engine temperature, engine throttle position, and other variables.
Throttle Sensor
Idle Switch
Water Temperature
Switch
Vehicle
Speed
Sensor
Transaxle
Control Unit
Fluid Temperature
Switch
Pulse
Generator
or Transaxle
Sensor
A/C
Cut-Off
Relay
Solenoid Actuator
Valves
O/D
Off
O/D Off Indicator
Inhibitor
Switch
Mode
Switch
Overdrive
Switch
Kickdown
Switch
Brake Light
Switch
Input
Output
Cruise Control Switch
Figure 21-30. This is an ECM-controlled rear drive axle assem-
bly. ECM can energize two electromagnets on each drive axle
to engage each drive wheel as needed for maximum traction.
(Honda Motor Co.)
Electromagnet
Ring Gear
Drive Shaft
Driveaxle Differential Assembly Planetary Gears
Review Questions—Chapter 21
Answer the following questions using the information
provided in this chapter.
1. How do anti-lock brakes improve safety?
2. Explain the fi ve major parts of ABS.
3. How does ABS prevent tire skid?
4. A customer complains of pedal rise and pedal vibration
during hard braking. The car has ABS. Technician A says
that this is normal with many ABS systems. It indicates
that the hydraulic actuator is cycling pressure to the brake
assemblies. Technician B says that the car must be taken
for a test drive to fully analyze the symptoms. Who is right?
(A) A only.
(B) B only.
(C) Both A and B.
(D) Neither A nor B.