On-Board Diagnostic Test For Charging System; Removal And Installation; Battery Temperature Sensor; Generator - Jeep 1997 Grand Cherokee Service Manual

ZG
DIAGNOSIS AND TESTING (Continued)
and a voltmeter reading of 15 volts is obtained.
Immediately record ammeter reading. Do not apply
load to system longer than 15 seconds as damage to
test equipment may result.
CAUTION: When adjusting rheostat load, do not
allow voltage to rise above 16 volts. Damage to the
battery and electrical system components may
result.
(6) The ammeter reading must meet the Minimum
Test Amps specifications as displayed in the Genera-
tor Ratings chart. This can be found in the Specifica-
tions section at the end of this group. A label stating
a part reference number is attached to the generator
case. On some engines this label may be located on
the bottom of the case. Compare this reference num-
ber to the Generator Rating chart.
(7) Remove volt/amp tester.
(8) Remove jumper wire.
(9) Use the DRB scan tool to erase the DTC. Refer
to the DRB screen for procedures.
RESULTS
• If amp reading meets specifications in Test 2,
generator is OK.
• If amp reading is less than specified in Test 2,
and wire resistance (voltage drop) tests were OK, the
generator should be replaced. Refer to Removal and
Installation in this group for procedures.
• If Test 2 results were OK, but Test 1 results
were not, the problem is in EVR circuitry. Refer to
appropriate Powertrain Diagnostic Procedures man-
ual for diagnosis.

BATTERY TEMPERATURE SENSOR

To perform a complete test of this sensor and its
circuitry, refer to the appropriate Powertrain Diag-
nostic Procedures manual. To test the sensor only,
refer to the following:
(1) The sensor is located under the battery and is
attached to the battery tray (Fig. 2). A two-wire pig-
tail harness is attached directly to the sensor. The
opposite end of this harness connects the sensor to
the engine wiring harness.
(2) Disconnect the two-wire pigtail harness from
the engine harness.
(3) Attach ohmmeter leads to the wire terminals of
the pigtail harness.
(4) At room temperature of 25° C (75–80° F), an
ohmmeter reading of 9,000 (9K) to 11,000 (11K) ohms
should be observed.
(5) If reading is above or below the specification,
replace the sensor.
(6) Refer to the Removal and Installation section
for procedures.
SENSOR HARNESS BATTERYTRAY
Fig. 2 Battery Temperature Sensor
ON-BOARD DIAGNOSTIC TEST FOR CHARGING
SYSTEM
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the On-Board Diagnostic
(OBD) system. Some circuits are checked continu-
ously and some are checked only under certain con-
ditions.
For DTC information, refer to Diagnostic Trouble
Codes in Group 25, Emission Control System. This
will include a complete list of DTC's including DTC's
for the charging system.

REMOVAL AND INSTALLATION

GENERATOR

WARNING: DISCONNECT NEGATIVE CABLE FROM
BATTERY BEFORE REMOVING BATTERY OUTPUT
WIRE FROM GENERATOR. FAILURE TO DO SO
CAN RESULT IN INJURY.
(1) Disconnect negative battery cable.
(2) Remove generator drive belt. Refer to Group 7,
Cooling System for procedure.
(3) Remove generator pivot and mounting bolts/nut
(Fig. 3) or (Fig. 4). Position generator for access to
wire connectors.
(4) Remove nuts from harness holddown, battery
terminal, ground terminal and 2 field terminals.
Remove wire connectors. A typical generator wiring
harness is shown in (Fig. 5). Wiring harness routing
as shown may be slightly different depending on
vehicle model and/or engine. Refer to Group 8W, Wir-
ing Diagrams for additional information.
(5) Remove generator.
BATTERY TEMPERATURE SENSOR ING HARNESS ENGINE WIR-
CHARGING SYSTEM 8C - 5