1994 JEEP WRANGLER charging

87 and 30. Continuity should not be present between
terminals number 87A and 30.
(8) Disconnect jumper wires from relay and 12
Volt power source.
If continuity or resistance tests did not pass, re-
place relay. If tests passed, refer to Group 8W, Wir-
ing Diagrams for additional circuit information. Also
refer to the appropriate Powertrain Diagnostic Proce-
dures manual for operation of the DRB scan tool.
STARTER MOTOR RELAY TEST
Refer to Group 8A, Battery/Starting/Charging/Sys-
tem Diagnostics, for starter motor relay testing.
INJECTOR TEST
Disconnect the injector wire connector from the in-
jector. Place an ohmmeter on the injector terminals.
Resistance reading should be approximately 14.5
ohms61.2 ohms at 20ÉC (68ÉF). Proceed to following
Injector Diagnosis chart.
FUEL SYSTEM PRESSURE TEST
Refer to the Fuel Delivery System section of this
group. See Fuel System Pressure Test.
ON-BOARD DIAGNOSTICS (OBD)
The Powertrain Control Module (PCM) has been
programmed to monitor many different circuits of the
fuel injection system. If a problem is sensed in a
monitored circuit often enough to indicate an actual
problem, a Diagnostic Trouble Code (DTC) is stored.
The DTC will be stored in the PCM memory for
eventual display to the service technician. If the
problem is repaired or ceases to exist, the PCM can-
cels the DTC after 51 engine starts.
Certain criteria must be met for a diagnostic trou-
ble code (DTC) to be entered into PCM memory. The
criteria may be a specific range of engine rpm, en-
gine temperature and/or input voltage to the PCM.
It is possible that a DTC for a monitored circuit
may not be entered into memory even though a mal-
function has occurred. This may happen because one
of the DTC criteria for the circuit has not been met.
Example: assume that one of the criteria for the
MAP sensor circuit is that the engine must be oper-
ating between 750 and 2000 rpm to be monitored for
a DTC. If the MAP sensor output circuit shorts to
ground when the engine rpm is above 2400 rpm, a 0
volt input will be seen by the PCM. A DTC will not
be entered into memory because the condition does
not occur within the specified rpm range.
A DTC indicates that the powertrain control mod-
ule (PCM) has recognized an abnormal signal in a
circuit or the system. A DTC may indicate the result
of a failure, but never identify the failed component
directly.There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to
the following Monitored Circuits and Non-Monitored
Circuits in this section.
MONITORED CIRCUITS
The powertrain control module (PCM) can detect
certain problems in the fuel injection system.
Open or Shorted Circuit- The PCM can deter-
mine if sensor output (which is the input to PCM) is
within proper range. It also determines if the circuit
is open or shorted.
Output Device Current Flow- The PCM senses
whether the output devices are hooked up.
If there is a problem with the circuit, the PCM
senses whether the circuit is open, shorted to ground
(-), or shorted to (+) voltage.
Oxygen Sensor- The PCM can determine if the
oxygen sensor is switching between rich and lean.
This is, once the system has entered Closed Loop. Re-
fer to Open Loop/Closed Loop Modes Of Operation in
the Component Description/System Operation section
for an explanation of Closed (or Open) Loop opera-
tion.
NON-MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems or conditions that could have malfunctions
that result in driveability problems. A Diagnostic
Trouble Code (DTC) may not be displayed for these
conditions.
Fuel Pressure: Fuel pressure is controlled by the
vacuum assisted fuel pressure regulator. The PCM
cannot detect a clogged fuel pump inlet filter, clogged
in-line fuel filter, or a pinched fuel supply or return
line. However, these could result in a rich or lean
condition causing an oxygen sensor DTC to be stored
in the PCM.
Secondary Ignition Circuit: The PCM cannot
detect an inoperative ignition coil, fouled or worn
spark plugs, ignition cross firing, or open circuited
spark plug cables.
Engine Timing: The PCM cannot detect an incor-
rectly indexed timing chain, camshaft sprocket or
crankshaft sprocket. The PCM also cannot detect an
incorrectly indexed distributor. However, these could
result in a rich or lean condition causing an oxygen
sensor DTC to be stored in the PCM.
Cylinder Compression: The PCM cannot detect
uneven, low, or high engine cylinder compression.
Exhaust System: The PCM cannot detect a
plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions: The PCM cannot de-
termine if the fuel injector is clogged, or the wrong
injector is installed. However, these could result in a
rich or lean condition causing an oxygen sensor DTC
to be stored in the PCM.
14 - 48 FUEL SYSTEMJ

DIAGNOSTIC TROUBLE CODE DESCRIPTIONSÐCONTINUED
Diagnostic
Trouble
CodeDRB Scan Tool
DisplayDescription of Diagnostic Trouble Code
41**..........Generator Field Not
Switching ProperlyAn open or shorted condition detected in the generator field control circuit.
42* ..........Auto Shutdown Relay
Control CircuitAn open or shorted condition detected in the auto shutdown relay circuit.
44* ..........Battery Temp Sensor
Volts out of LimitAn open or shorted condition exists in the engine coolant temperature sensor
circuit or a problem exists in the PCM's battery temperature voltage circuit.
46**..........Charging System Voltage
Too HighBattery voltage sense input above target charging voltage during engine
operation.
47**..........Charging System Voltage
Too LowBattery voltage sense input below target charging during engine operation.
Also, no significant change detected in battery voltage during active test of
generator output.
51**.......... O2SSignal Stays Below
Center (Lean)Oxygen sensor signal input indicates lean air/fuel ratio condition during
engine operation.
52**.......... O2SSignal Stays Above
Center (Rich)Oxygen sensor signal input indicates rich air/fuel ratio condition during
engine operation.
53* ..........Internal PCM Failure PCM Internal fault condition detected.
or
PCM Failure SPI
CommunicationsPCM Internal fault condition detected.
54* .......... NoCamSync Signal at
PCMNo fuel sync (camshaft signal) detected during engine cranking.
55* .......... N/ACompletion of diagnostic trouble code display on the Malfunction Indicator
Lamp (Check Engine Lamp).
62* .......... PCMFailure SPI miles not
storedUnsuccessful attempt to update SPI miles in the PCM EEPROM.
63* .......... PCMFailure EEPROM
Write DeniedUnsuccessful attempt to write to an EEPROM location by the PCM.
* Check Engine Lamp will not illuminate at all times if this Diagnostic Trouble Code was recorded. Cycle Ignition key as
described in manual and observe code flashed by Check Engine lamp.
** Check Engine Lamp will illuminate during engine operation if this Diagnostic Trouble Code was recorded.
JFUEL SYSTEM 14 - 53

Fig. 7 Load 50% Cold Crank Rating Note Voltage
JBATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 5

Fig. 3 Test Positive Battery Cable Resistance
(Typical)
Fig. 4 Test Ground Circuit Resistance
Fig. 5 Test Starter Motor Ground (Typical)
Fig. 6 Continuity Test Between Solenoid Terminal
and Field Coil Terminal
JBATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 11

Fig. 8 Power Distribution CenterÐXJ
8A - 12 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICSJ

Fig. 1 Charging System Components (Typical)
8A - 14 BATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICSJ

JBATTERY/STARTING/CHARGING SYSTEMS DIAGNOSTICS 8A - 19

Wiring Diagram Name Sheet Number
ABS Accelerator Sensor........................59
ABS Control Module.....................57, 58, 59
ABS Control Module Connector...................60
ABS Motor Pump Relay........................57
ABS Power Relay............................57
A/C Blower Switch............................50
A/C Compressor.............................49
A/C Low Pressure Switch.......................49
A/C Relay.................................49
A/C Thermostat..............................50
Accessory Illumination.........................32
Air Conditioning System (4.0L).................49, 50
A/C Blower Switch..........................50
A/C Compressor............................49
A/C Low Pressure Switch.....................49
A/C Relay................................49
A/C Thermostat............................50
Field Jumper..............................50
Powertrain Control Module.....................49
Anti-Lock Brake System (TEVES).............57, 58, 59
ABS Accelerator Sensor.......................59
ABS Control Module....................57, 58, 59
ABS Motor Pump Relay.......................57
ABS Power Relay...........................57
Brake Pedal Travel Sensor.....................57
Data Link Connector.........................57
Diode..................................58
Hydraulic Actuation Unit......................58
Left Front Wheel Sensor......................59
Left Rear Wheel Sensor.......................59
Power Distribution Center.....................57
Pump Motor..............................57
Pump Motor Sensor.........................57
Right Front Wheel Sensor.....................59
Right Rear Wheel Sensor......................59
Automatic Shut-Down Relay...................11, 17
Back-Up Lamps...........................51, 52
Back-Up Lamp Switch..........................7
Battery................................1,3,5
Blower Motor...............................47
Blower Resistor.............................47
Blower Switch..............................47
Body Harness Connector........................36
Brake Pedal Travel Sensor.......................57
Brake Warning Switch..........................9
Bulkhead Connector........................65, 66
Buzzer Module..............................36
Camshaft Position Sensor....................12, 18
Center High Mounted Stop Lamp..................52
Charging System 2.5L Engine...................3,4
Battery..................................3
Generator.................................3
Power Distribution Center......................4