650 Auto Electricity and Electronics
Copyright by Goodheart-Willcox Co., Inc.
a box or place it in a shipping container. Place warning tape
or high-voltage warning labels on the outside of the box
or shipping container to warn others of the high-voltage
danger inside.
Checking HV Battery Pack Relays
and Contactors
If the trouble codes and symptoms indicate battery
power is okay but battery power is not reaching the power
control module, check the operation of the battery relays
and contactors. The contactors turn such a high electrical
load on and off that their lugs can become burned and pit-
ted. If burned enough, the lugs will develop high resistance
and will not be able to carry enough current to the power
control module and motor-generator. Refer to factor service
information for relay and contactor test points.
To make a pinpoint test on a high-voltage contactor, fi rst
remove or disconnect the HV battery pack. Then, measure
the resistance across the closed contactors with the ignition
key on and then off. If your measurements are not within
specifi cations, replace the contactors. See Figure 33-8.
Hybrid Power Cable Service
The hybrid power cables are normally trouble free.
However, they can become damaged during a collision
or their metal ends can become loose or corroded. Some
high-voltage cables have special watertight terminal ends,
Figure 33-9. However, most hybrids use an eye-type con-
nector that is secured to a threaded metal stud with a nut.
Figure 33-7. Remove the metal cover over the HV battery pack.
This will expose the battery modules, battery ECU, cooling fans,
and other units that affect battery performance. (Toyota)
Upper Cover
Service
Hole Cover
Cooling
Fan
HV Battery
Modules
Junction
Block
Figure 33-8. Contactor lugs can become burned and pitted after
shutting high voltage on and off thousands of times. If contactor
terminals show high resistance when closed (battery pack dis-
connected from circuit), they should be replaced.
~V
OFF
V
Ω
mA
mA
A
~
Ω
Figure 33-9. This power cable has a waterproof terminal end.
O-ring seals on the power control module or the motor-
generator housing keeps water out of the system.