Chapter 33 Hybrid Drive Systems Diagnosis and Repair 653
Copyright by Goodheart-Willcox Co., Inc.
The instrument panel combination meter will also indicate poor
electrical drive performance during all-electric (motor-generator
driven) acceleration and regenerative braking.
When replacing a motor-generator, refer to the service
manual for instructions, since part locations and procedures
vary from one make to another. The most common motor-
generator design requires you to remove the transaxle or
transmission to access the motor-generator assembly.
Figure 33-14 outlines the major steps for removing
one motor-generator from one particular specifi c vehicle.
After removing the fl ex plate, a plastic sleeve is installed
between the armature and stator to hold them apart during
disassembly. This prevents the armature from contacting
and damaging the magnets and coils in the stator. A puller
is then used to remove the armature, which is press fi t into
the end of the engine crankshaft.
Figure 33-15 shows a position sensor for the armature
of a hybrid motor-generator. Since the sensor is fastened to
the back of the cylinder block with this model vehicle, the
transaxle and motor-generator must be removed to service it.
As discussed in Chapter 22, some hybrids use two or three
motor-generators to provide all-electric drive or electric assist.
The motor-generators can be located inside the transmission or in
the rear drive axle assembly with all-wheel drive vehicles. Refer
to manufacturer service information to replace these units.
Hybrid Wiring Problems
As with any electrical/electronic circuit, poor electri-
cal connections, broken wire conductors, shorted wires,
and similar problems can be diffi cult to diagnose and repair
in a modern hybrid vehicle. When your scan tool shows a
Figure 33-14. Note the major steps for removing one type of motor-
generator. This particular unit mounts on the rear of the engine and
in front of the transaxle or transmission. A—The fl ex plate over the
motor-generator can be removed after removing the cap screws
that secure it to the crankshaft fl ange. B—A plastic sleeve should be
installed between the rotor and stator of the motor-generator assem-
bly. It will keep magnetism from pulling the two together when you are
trying to remove the rotor. C—A wheel puller is then used to force the
rotor from the crankshaft. With the puller bolted to the rotor, tighten
the puller screw to slowly force off the press fi t rotor. (Toyota)
Puller
Studs
A
B
C
Armature
Plastic
Ring
Sleeve
Stator
Flex Plate
Figure 33-13. The air cooling system for the HV battery pack
and power control module is serviced the same way you service
a climate control fan and wiring. After removing the cover, ducts,
and fasteners, the blower motor assembly can be removed for
replacement. (Toyota)
Blower