Jeep Cherokee 2000 Service Manual - page 310
battery has been charged, boosted, or loaded a few
minutes prior to the test, the battery will be some-
what warmer. See the Load Test Temperature chart
for the proper loaded voltage reading.
(7) If the voltmeter reading falls below 9.6 volts, at
a minimum battery temperature of 21° C (70° F), the
battery is faulty and must be replaced.
IGNITION-OFF DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to twenty-five milliamperes (0.005 to 0.025 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. The twenty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.
Excessive IOD can be caused by:
•
Electrical items left on.
•
Faulty or improperly adjusted switches.
•
Faulty or shorted electronic modules and compo-
nents.
•
An internally shorted generator.
•
Intermittent shorts in the wiring.
If the IOD is over twenty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw table for more information.
Fig. 12 Remove Surface Charge from Battery -
Typical
Fig. 13 Load 50% CCA Rating - Note Voltage -
Typical
Load Test Temperature
Minimum Voltage
Temperature
°F
°C
9.6 volts
70° and above
21° and above
9.5 volts
60°
16°
9.4 volts
50°
10°
9.3 volts
40°
4°
9.1 volts
30°
-1°
8.9 volts
20°
-7°
8.7 volts
10°
-12°
8.5 volts
0°
-18°
XJ
BATTERY
8A - 13
DIAGNOSIS AND TESTING (Continued)