Jeep 200 Cherokee Service Manual page 323

8A - 6 BATTERY
DIAGNOSIS AND TESTING (Continued)
tested as a complete system. In order for the engine
to start and the battery to charge properly, all of the
components that are used in these systems must per-
form within specifications. It is important that the
battery, starting system and charging system be thor-
oughly tested and inspected any time a battery needs
to be charged or replaced. The cause of abnormal dis-
charge, overcharging or early battery failure must be
diagnosed and corrected before a battery is replaced
and before a vehicle is returned to service. The ser-
vice information for these systems has been sepa-
rated within this service manual to make it easier to
locate the specific information you are seeking. How-
ever, when attempting to diagnose any of these sys-
tems, it is important
interdependency in mind.
The diagnostic procedures used for the battery,
starting system and charging system include the
most basic conventional diagnostic methods, to the
more sophisticated On-Board Diagnostics (OBD) built
into the Powertrain Control Module (PCM). Use of an
induction-type milliampere ammeter, a volt/ohmme-
ter, a battery charger, a carbon pile rheostat (load
tester) and a 12-volt test lamp may be required. All
OBD-sensed systems are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for any failure it detects. Refer to
Charging System, On-Board Diagnostic Test in
the index of this service manual for the location of
the proper on-board diagnostic test procedures.
The battery must be completely charged and the
top, posts and terminal clamps should be properly
cleaned and inspected before diagnostic procedures
are performed. Refer to Battery in the index of this
service manual for the location of the proper battery
cleaning and inspection procedures. Refer to Battery
Charging in the index of this service manual for the
location of the proper battery charging procedures.
WARNING:
• IF THE BATTERY SHOWS SIGNS OF FREEZ-
ING, LEAKING, LOOSE POSTS, OR LOW ELECTRO-
LYTE LEVEL, DO NOT TEST, ASSIST-BOOST, OR
CHARGE. THE BATTERY MAY ARC INTERNALLY
AND EXPLODE. PERSONAL INJURY AND/OR VEHI-
CLE DAMAGE MAY RESULT.
• EXPLOSIVE HYDROGEN GAS FORMS IN AND
AROUND THE BATTERY. DO NOT SMOKE, USE
FLAME, OR CREATE SPARKS NEAR THE BATTERY.
PERSONAL INJURY AND/OR VEHICLE DAMAGE
MAY RESULT.
• THE BATTERY CONTAINS SULFURIC ACID,
WHICH IS POISONOUS AND CAUSTIC. AVOID CON-
TACT WITH THE SKIN, EYES, OR CLOTHING. IN
THE EVENT OF CONTACT, FLUSH WITH WATER
that you keep their
AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT
OF THE REACH OF CHILDREN.
• IF THE BATTERY IS EQUIPPED WITH REMOV-
ABLE CELL CAPS, BE CERTAIN THAT EACH OF
THE CELL CAPS IS IN PLACE AND TIGHT BEFORE
THE BATTERY IS RETURNED TO SERVICE. PER-
SONAL INJURY AND/OR VEHICLE DAMAGE MAY
RESULT FROM LOOSE OR MISSING CELL CAPS.
The condition of a battery is determined by two cri-
teria:
1. State-Of-Charge
This can be determined by checking the specific grav-
ity of the battery electrolyte (built-in test indicator or
hydrometer test), or by checking the battery voltage
(open-circuit voltage test).
2. Cranking Capacity
This can be determined by performing a battery load
test, which measures the ability of the battery to
supply high-amperage current.
First, determine the battery state-of-charge. This
can be done in one of three ways. If the battery has a
built-in test indicator, view the test indicator to
determine the state-of-charge. If the battery has no
test indicator but does have removable cell caps, per-
form the hydrometer test to determine the state-of-
charge. If the battery cell caps are not removable, or
a hydrometer is not available, perform the open-cir-
cuit voltage test to determine the state-of-charge.
The battery must be charged before proceeding
with a load test if:
• The battery built-in test indicator has a black or
dark color visible.
• The temperature corrected specific gravity of the
battery electrolyte is less than 1.235.
• The battery open-circuit voltage is less than 12.4
volts.
A battery that will not accept a charge is faulty,
and must be replaced. Further testing is not
required. A fully-charged battery must be load tested
to determine its cranking capacity. A battery that is
fully-charged, but does not pass the load test, is
faulty and must be replaced.
NOTE: Completely discharged batteries may take
several hours to accept a charge. Refer to Battery
Charging in the index of this service manual for the
location of the proper battery charging procedures.
A battery is fully-charged when:
• All battery cells are gassing freely during charging.
• A green color is visible in the sight glass of the
battery built-in test indicator.
• Three corrected specific gravity tests, taken at
one-hour intervals, indicate no increase in the spe-
cific gravity of the battery electrolyte.
• Open-circuit voltage of the battery is 12.4 volts
or greater.
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