4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(1) Attach J-hooks around the axle shaft tubes out-
board of the shock absorber.
(2) Place the sling crossbar under and forward of
the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to
unlock the steering column.
(5) Clamp the steering wheel with the front wheels
in the straight ahead position. Do not use the steer-
ing column lock as a substitute for a clamping de-
vice.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(6) Shift the transmission to a forward gear and
the transfer case to NEUTRAL.
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(1) Attach J-hooks around the axle shaft tubes out-
board of the shock absorber.
(2) Place the sling crossbar under and forward of
the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to
unlock the steering column.
(5) Clamp the steering wheel with the front wheels
in the straight ahead position. Do not use the steer-
ing column lock as a substitute for a clamping de-
vice.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(6) Shift the transmission to PARK and the trans-
fer case to NEUTRAL.
4WD, Selec-Trac (242 Full-Time 4WD Transfer
Case) And Automatic Transmission
(1) Attach J-hooks around the axle shaft tubes out-
board of the shock absorber.
(2) Place the sling crossbar under and forward of
the bumper.
(3) Attach safety chains around the frame rails.
(4) Turn the ignition switch to the OFF position to
unlock the steering column.
(5) Clamp the steering wheel with the front wheels
in the straight ahead position. Do not use the steer-
ing column lock as a substitute for a clamping de-
vice.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(6) Shift the transmission to PARK and the trans-
fer case to NEUTRAL.TOWING WHEN IGNITION KEYS ARE NOT
AVAILABLE
VEHICLE DOORS UNLOCKED
2WD Vehicles
Either one of two methods can be used:
²tow the vehicle with the drive shaft removed (refer
to Sling-Type, Front-End Towing); or
²place a tow dolly under the rear wheels (Fig. 14)
and tow with the front end raised (refer to Sling-
Type, Front-End Towing).
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Manual Transmission
(1) Shift the manual transmission to a forward
gear.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front
wheels raised (refer to Sling-Type, Front-End Tow-
ing).
4WD, Command-Trac (231 Part-Time 4WD
Transfer Case) And Automatic Transmission
(1) Check and ensure that the automatic transmis-
sion is in PARK.
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front
wheels raised (refer to Sling-Type, Front-End Tow-
ing).
4WD, Selec-Trac (242 Full-Time 4WD Transfer
Case) And Automatic Transmission
(1) Check and ensure that the automatic transmis-
sion is in PARK.
Fig. 14 Sling-Type, Front-End Towing With Rear
Wheels On A Tow Dolly
JLUBRICATION AND MAINTENANCE 0 - 11
When the transfer case is in the NEUTRAL po-
sition, both axles are disengaged from the pow-
ertrain. This allows the vehicle to be towed
without removing the drive shafts.
(2) Shift the transfer case to NEUTRAL.
(3) The vehicle can now be towed with the front
wheels raised (refer to Sling-Type, Front-End Tow-
ing).
VEHICLE DOORS LOCKED
Place a tow dolly under the rear wheels (Fig. 14)
and tow with the front end raised (refer to Sling-
Type, Front-End Towing).
4WD EMERGENCY TOWINGÐTRANSFER CASE
NOT SHIFTED TO NEUTRAL
When a situation arises and the transfer case can-
not be shifted to NEUTRAL, any of the following
methods can be used to tow a 4WD vehicle.
Drive shafts not removed, place the rear
wheels on a tow dolly and tow with the front
end raised.
Drive shafts not removed, place the front
wheels on a tow dolly and tow with the rear end
raised.
Rear drive shaft removed, tow with the front
end raised.
Front drive shaft removed, tow with the rear
end raised.
Both drive shafts removed, tow with all four
wheels on the road surface.
(1) Turn ignition key switch to the unlocked (OFF)
position.
(2) Shift the transmission to the NEUTRAL posi-
tion.
(3) Determine the method by which the vehicle
will be towed and prepare the vehicle for towing.
(4) Connect the vehicle to the tow vehicle. Refer to
the applicable procedure.
FLAT TOWING (4 TIRES/WHEELS ON
SURFACE)
Tow a vehicle in this manner only when all four
wheels will freely rotate. Prepare the vehicle accord-
ing to the following procedures.
2WD VEHICLES
(1) Mark the drive shaft and the axle drive pinion
gear shaft yoke for installation alignment reference.
(2) Remove the drive shaft. Install a protective
covering over the drive shaft U-joints to retain them
assembled and protected.
(3) Cover the open end of the transmission exten-
sion housing.4WD VEHICLES
(1) Mark the drive shafts and the axle drive pinion
gear shaft yokes for installation alignment reference.
(2) Remove the drive shafts. Install a protective
covering over the drive shaft U-joints/CV-joints to re-
tain them assembled and protected.
(3) Cover the exposed ends of the transfer case.
CAUTION: Whenever a drive shaft has been re-
moved and installed, check the transmission fluid
level of the transmission and transfer case. Driving
a vehicle with low tranfer case fluid can damage the
transmission and transfer case.
EMERGENCY TOW HOOKS
WARNING: REMAIN AT A SAFE DISTANCE FROM A
VEHICLE THAT IS BEING TOWED VIA ITS TOW
HOOKS. THE TOW STRAPS/CHAINS COULD POSSI-
BLY BREAK AND CAUSE SERIOUS INJURY.
Some Jeeptvehicles are equipped with emergency
tow hooks located at the front end (Fig. 15). Some
Jeeptvehicles also have emergency tow hooks lo-
cated at the rear ende. The tow hooks should be used
forEMERGENCYpurposes only.
CAUTION: DO NOT use emergency tow hooks for
tow truck hook-up or highway towing.
Fig. 15 Emergency Front Tow HooksÐXJ & YJ
Vehicles
0 - 12 LUBRICATION AND MAINTENANCEJ
(4) Extra close attention should be given to exter-
nal key lock cylinders during the autumn and winter
months to ensure protection from water and ice.(5) Extra close attention should also be given to
the hood latch components to ensure proper function-
ing.
HEADLAMPS
RECOMMENDED MAINTENANCE
Approximately every six months the headlamps
should be displayed on a vertical test surface. This
will ensure that the headlamps are positioned for
safe night-time driving.
BEAM AIM ADJUSTMENT
(1) Changes in the vehicle front and rear suspen-
sion will alter the headlamp beam patterns and this
can cause unsafe night-time driving conditions.
(2) If a vehicle is loaded the headlamp beam pat-
terns should be displayed on an vertical test surface
and the headlamps re-aimed.
(3) Observe the headlamp beam patterns on an ap-
propriate vertical test surface and, if necessary, ad-
just the headlamp beam aim.
(4) If necessary, refer to Group 8LÐLamps for
headlamp aim adjustment procedures.
BODY LUBRICANT SPECIFICATIONS
Fig. 11 Hood Hinge LubricationÐXJ Vehicles
JLUBRICATION AND MAINTENANCE 0 - 35
MULTI-PORT FUEL INJECTION (MFI)ÐCOMPONENT DESCRIPTION/SYSTEM
OPERATION
INDEX
page page
Air Conditioning (A/C) Clutch RelayÐPCM Output.24
Air Conditioning (A/C) ControlsÐPCM Input.... 19
Auto Shut Down (ASD) RelayÐPCM Output.... 24
Automatic Shut Down (ASD) SenseÐPCM Input . 19
Battery VoltageÐPCM Input................ 19
Brake SwitchÐPCM Input.................. 20
Camshaft Position SensorÐPCM Input........ 20
Crankshaft Position SensorÐPCM Input....... 20
Data Link ConnectorÐPCM Input............ 20
Data Link ConnectorÐPCM Output........... 24
EMR LampÐPCM Output.................. 24
Engine Coolant Temperature SensorÐPCM Input . 21
Extended Idle SwitchÐPCM Input............ 21
Fuel InjectorsÐPCM Output................ 25
Fuel Pressure Regulator................... 30
Fuel Pump RelayÐPCM Output............. 25
Fuel Rail............................... 30
General Information....................... 17
Generator FieldÐPCM Output............... 25
Generator LampÐPCM Output.............. 25
Idle Air Control (IAC) MotorÐPCM Output...... 25
Ignition Circuit SenseÐPCM Input............ 21
Ignition CoilÐPCM Output.................. 26Intake Air Temperature SensorÐPCM Input.... 20
Malfunction Indicator LampÐPCM Output...... 26
Manifold Absolute Pressure (MAP) SensorÐ
PCM Input............................ 21
Open Loop/Closed Loop Modes of Operation . . . 27
Overdrive/Override Switch.................. 22
Oxygen (O2S) SensorÐPCM Input........... 22
Park/Neutral SwitchÐPCM Input............. 22
Power Ground........................... 22
Power Steering Pressure SwitchÐPCM Input . . . 22
Powertrain Control Module (PCM)............ 18
Radiator Fan RelayÐPCM Output............ 26
SCI ReceiveÐPCM Input.................. 22
SCI TransmitÐPCM Output................. 26
Sensor ReturnÐPCM Input................. 23
Shift IndicatorÐPCM Output................ 26
Speed ControlÐPCM Input................. 23
Speed ControlÐPCM Output................ 27
TachometerÐPCM Output.................. 27
Throttle Body............................ 29
Throttle Position Sensor (TPS)ÐPCM Input..... 23
Torque Converter Clutch RelayÐPCM Output . . . 27
Vehicle Speed SensorÐPCM Input........... 23
GENERAL INFORMATION
All 2.5L 4 cylinder and 4.0L 6 cylinder engines are
equipped with sequential Multi-Port Fuel Injection
(MFI). The MFI system provides precise air/fuel ra-
tios for all driving conditions.
The Powertrain Control Module (PCM) operates
the fuel system. The PCM was formerly referred to
as the SBEC or engine controller. The PCM is a pre-
programmed, dual microprocessor digital computer.
It regulates ignition timing, air-fuel ratio, emission
control devices, charging system, speed control, air
conditioning compressor clutch engagement and idle
speed. The PCM can adapt its programming to meet
changing operating conditions.
Powertrain Control Module (PCM) Inputsrep-
resent the instantaneous engine operating conditions.
Air-fuel mixture and ignition timing calibrations for
various driving and atmospheric conditions are pre-
programmed into the PCM. The PCM monitors and
analyzes various inputs. It then computes engine fuel
and ignition timing requirements based on these in-
puts. Fuel delivery control and ignition timing will
then be adjusted accordingly.
Other inputs to the PCM are provided by the brake
light switch, air conditioning select switch and the
speed control switches. All inputs to the PCM are
converted into signals.
Electrically operated fuel injectors spray fuel in
precise metered amounts into the intake port directlyabove the intake valve. The injectors are fired in a
specific sequence by the PCM. The PCM maintains
an air/fuel ratio of 14.7 to 1 by constantly adjusting
injector pulse width. Injector pulse width is the
length of time that the injector opens and sprays fuel
into the chamber. The PCM adjusts injector pulse
width by opening and closing the ground path to the
injector.
Manifold absolute pressure (air density) and engine
rpm (speed) are the primary inputs that determine
fuel injector pulse width. The PCM also monitors
other inputs when adjusting air-fuel ratio.
Inputs That Effect Fuel Injector Pulse Width
²Exhaust gas oxygen content
²Engine coolant temperature
²Manifold absolute pressure (MAP)
²Engine speed
²Throttle position
²Battery voltage
²Air conditioning selection
²Transmission gear selection (automatic transmis-
sions only)
²Speed control
The powertrain control module (PCM) adjusts igni-
tion timing by controlling ignition coil operation. The
ignition coil receives battery voltage when the igni-
tion key is in the run or starter position. The PCM
provides a ground for the ignition coil. The coil dis-
JFUEL SYSTEM 14 - 17
ing the IAC motor pintle in and out of the air control
passage. The IAC motor is positioned when the igni-
tion key is turned to the On position.
A (factory adjusted) set screw is used to mechani-
cally limit the position of the throttle body throttle
plate.Never attempt to adjust the engine idle
speed using this screw.All idle speed functions are
controlled by the PCM.
IGNITION COILÐPCM OUTPUT
System voltage is supplied to the ignition coil pos-
itive terminal. The powertrain control module (PCM)
operates the ignition coil.Base (initial) ignition
timing is not adjustable.The PCM adjusts ignition
timing to meet changing engine operating conditions.
The ignition coil is located near the ignition distrib-
utor (Fig. 22).
Refer to Group 8D, Ignition System for additional
information.
MALFUNCTION INDICATOR LAMPÐPCM OUTPUT
The Malfunction Indicator Lamp (formerly referred
to as the Check Engine Lamp) illuminates on the in-
strument panel each time the ignition key is turned
on. It will stay on for three seconds as a bulb test.
If the powertrain control module (PCM) receives an
incorrect signal, or no signal from certain sensors or
emission related systems, the lamp is turned on. This
is a warning that the PCM has recorded a system or
sensor malfunction. In some cases, when a problem is
declared, the PCM will go into a limp-in mode. This
is an attempt to keep the system operating. It signals
an immediate need for service.
The lamp can also be used to display a Diagnostic
Trouble Code (DTC). Cycle the ignition switch On-
Off-On-Off-On within three seconds and any codes
stored in the PCM memory will be displayed. This is
done in a series of flashes representing digits. Refer
to On-Board Diagnostics in the General Diagnosis
section of this group for more information.
RADIATOR FAN RELAYÐPCM OUTPUT
XJ MODELS ONLY
The electric radiator cooling fan used in XJ models
(equipped with 4.0L engine, heavy duty cooling
and/or air conditioning) is controlled by the power-
train control module (PCM) through radiator fan re-
lay. The relay is energized when coolant temperature
is above 103ÉC (217ÉF). It will then de-energize when
coolant temperature drops to 98ÉC (208ÉF). Refer to
Group 7, Cooling Systems for more information.
The relay is located in the power distribution cen-
ter (PDC) (Fig. 23).
The electric radiator cooling fan is not used on YJ
models.
SCI TRANSMITÐPCM OUTPUT
SCI Transmit is the serial data communication
transmit circuit for the DRB scan tool. The power-
train control module (PCM) transmits data to the
DRB through the SCI Transmit circuit.
SHIFT INDICATORÐPCM OUTPUT
Vehicles equipped with manual transmissions have
an Up-Shift indicator lamp. The lamp is controlled
by the powertrain control module (PCM). The lamp
illuminates on the instrument panel to indicate when
the driver should shift to the next highest gear for
best fuel economy. The PCM will turn the lamp OFF
after 3 to 5 seconds if the shift of gears is not per-
formed. The up-shift light will remain off until vehi-
cle stops accelerating and is brought back to range of
up-shift light operation. This will also happen if ve-
hicle is shifted into fifth gear.
The indicator lamp is normally illuminated when
the ignition switch is turned on and it is turned off
when the engine is started up. With the engine run-
ning, the lamp is turned on/off depending upon en-
gine speed and load.
Fig. 23 PDCÐXJ Models
Fig. 22 Ignition CoilÐTypical
14 - 26 FUEL SYSTEMJ
SPEED CONTROLÐPCM OUTPUT
Speed control operation is regulated by the power-
train control module (PCM). The PCM controls the
vacuum to the throttle actuator through the speed
control vacuum and vent solenoids. Refer to Group
8H for speed control information.
TACHOMETERÐPCM OUTPUT
The powertrain control module (PCM) supplies en-
gine rpm values to the instrument cluster tachome-
ter (if equipped). Refer to Group 8E for tachometer
information.
TORQUE CONVERTER CLUTCH RELAYÐPCM
OUTPUT
ALL 2.5L 4 CYL. WITH 3-SPEED AUTO. TRANS
4.0L 6 CYL. YJ MODELS WITH 3-SPEED AUTO.
TRANS
The transmission mounted torque converter clutch
(TCC) solenoid is used to control the torque con-
verter. The solenoid is controlled through the power-
train control module (PCM) and by the TCC relay.
This relay is used only on vehicles equipped with a
3-speed automatic transmission.
An electrical output signal is sent from the PCM to
the TCC relay after the PCM receives information
from the vehicle speed, MAP, throttle position and
engine coolant temperature sensors. After the TCC
relay receives this necessary information, it will send
a signal to the torque converter clutch solenoid to
control the torque converter.
On YJ models the TCC relay is located in the en-
gine compartment, on the cowl panel and near the
battery (Fig. 24). On XJ models the TCC relay is lo-
cated in the power distribution center (PDC) (Fig.
23).
OPEN LOOP/CLOSED LOOP MODES OF
OPERATION
As input signals to the powertrain control module
(PCM) change, the PCM adjusts its response to the
output devices. For example, the PCM must calculate
different injector pulse width and ignition timing for
idle than it does for wide open throttle (WOT). There
are several different modes of operation that deter-
mine how the PCM responds to the various input sig-
nals.
MODES
²Open Loop
²Closed Loop
During Open Loop modes, the powertrain control
module (PCM) receives input signals and responds
only according to preset PCM programming. Input
from the oxygen (O2S) sensor is not monitored dur-
ing Open Loop modes.
During Closed Loop modes, the PCM will monitor
the oxygen (O2S) sensor input. This input indicates
to the PCM whether or not the calculated injector
pulse width results in the ideal air-fuel ratio. This
ratio is 14.7 parts air-to-1 part fuel. By monitoring
the exhaust oxygen content through the O2S sensor,
the PCM can fine tune the injector pulse width. This
is done to achieve optimum fuel economy combined
with low emission engine performance.
The fuel injection system has the following modes
of operation:
²Ignition switch ON
²Engine start-up (crank)
²Engine warm-up
²Idle
²Cruise
²Acceleration
²Deceleration
²Wide open throttle (WOT)
²Ignition switch OFF
The ignition switch On, engine start-up (crank),
engine warm-up, acceleration, deceleration and wide
open throttle modes are Open Loop modes. The idle
and cruise modes, (with the engine at operating tem-
perature) are Closed Loop modes.
IGNITION SWITCH (KEY-ON) MODE
This is an Open Loop mode. When the fuel system
is activated by the ignition switch, the following ac-
tions occur:
²The powertrain control module (PCM) pre-posi-
tions the idle air control (IAC) motor.
²The PCM determines atmospheric air pressure
from the MAP sensor input to determine basic fuel
strategy.
²The PCM monitors the engine coolant temperature
sensor input. The PCM modifies fuel strategy based
on this input.
Fig. 24 TCC Relay LocationÐYJ Models
JFUEL SYSTEM 14 - 27
EXTENDED IDLE SWITCH TEST
OPTIONAL POLICE PACKAGE ONLY
OPERATION
The extended idle switch is used to raise the en-
gine idle speed to approximately 1000 rpm when the
shifter is in either the Park or Neutral position. A
rocker-type 2-wire switch (extended idle switch) is
mounted to the instrument panel.This switch is
available only with 4.0L engine when supplied
with the optional police package.
TESTING
The extended idle switch will control a ground cir-
cuit going to the powertrain control module (PCM).
When a ground signal (through this switch) has been
received at pin number 10 in the PCM, engine idle
speed will increase.
Bring the engine to normal operating temperature
and turn the extended idle switch to the ON position.
Engine speed should now increase to approximately
1000 rpm when the shifter is in either the Park or
Neutral position. If engine speed does not increase,
apply a good ground to pin number 10 at the PCM
using a small paper clip. Be careful not to damage
the wiring with the paper clip. If the engine speed
now increases, it can be assumed that the PCM is
functioning correctly. Check the instrument panel
mounted switch for a closed ground circuit when in
the ON position. If the engine speed will not increase
after applying a ground to pin number 10, replace
the PCM. Refer to Group 8W, Wiring Diagrams for
circuit and wiring information.
THROTTLE POSITION SENSOR (TPS) TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual. To test the
sensor only, refer to the following:
The throttle position sensor (TPS) can be tested
with a digital voltmeter. The center terminal of the
TPS is the output terminal (Figs. 39 or 40).
With the ignition key in the ON position, back-
probe the TPS connector. Check the TPS output volt-
age at the center terminal wire of the connector.
Check this at idle (throttle plate closed) and at wide
open throttle (WOT). At idle, TPS output voltage
should must be greater than 200 millivolts. At wide
open throttle, TPS output voltage must be less than
4.8 volts. The output voltage should increase gradu-
ally as the throttle plate is slowly opened from idle to
WOT.
TORQUE CONVERTER CLUTCH RELAY TEST
To test the relay only, refer to RelaysÐOperation/
Testing in this section of the group. To test the
torque converter clutch circuit and related compo-nents, refer to the appropriate Powertrain Diagnostic
Procedures manual for operation of the DRB scan
tool.
VEHICLE SPEED SENSOR TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual.
OXYGEN SENSOR (O2S) HEATING ELEMENT TEST
To perform a complete test of the O2S sensor (Fig.
41) and its circuitry, refer to DRB scan tool and ap-
propriate Powertrain Diagnostics Procedures manual.
To test the sensor only, refer to the following:
The oxygen sensor heating element can be tested
with an ohmmeter as follows:
With the sensor at room temperature 25 degrees C
(77 degrees F), disconnect the O2S sensor connector.
Connect the ohmmeter test leads across the white
wire terminals of the sensor connector. Resistance
should be between 5 and 7 ohms. Replace the sensor
if the ohmmeter displays an infinity (open) reading.
Fig. 39 TPS TestingÐ2.5L Engine
Fig. 40 TPS TestingÐ4.0L Engine
JFUEL SYSTEM 14 - 45
Excessive Oil Consumption: Although the PCM
monitors exhaust stream oxygen content through ox-
ygen sensor (closed loop), it cannot determine exces-
sive oil consumption.
Throttle Body Air Flow: The PCM cannot detect
a clogged or restricted air cleaner inlet or air filter
element.
Evaporative System: The PCM will not detect a
restricted, plugged or loaded EVAP canister.
Vacuum Assist: Leaks or restrictions in the vac-
uum circuits of vacuum assisted engine control sys-
tem devices are not monitored by the PCM. However,
a vacuum leak at the MAP sensor will be monitored
and a diagnostic trouble code (DTC) will be gener-
ated by the PCM.
Powertrain Control Module (PCM) System
Ground: The PCM cannot determine a poor system
ground. However, a DTC may be generated as a re-
sult of this condition.
Powertrain Control Module (PCM) Connector
Engagement: The PCM cannot determine spread or
damaged connector pins. However, a DTC may be
generated as a result of this condition.
HIGH AND LOW LIMITS
The powertrain control module (PCM) compares in-
put signal voltages from each input device. It will es-
tablish high and low limits that are programmed into
it for that device. If the input voltage is not within
specifications and other Diagnostic Trouble Code
(DTC) criteria are met, a DTC will be stored in mem-
ory. Other DTC criteria might include engine rpm
limits or input voltages from other sensors or
switches. The other inputs might have to be sensed
by the PCM when it senses a high or low input volt-
age from the control system device in question.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored Diagnostic Trouble Code (DTC) can be dis-
played by cycling the ignition key On-Off-On-Off-On
within three seconds and observing the Malfunction
Indicator Lamp. This lamp was formerly referred to
as the Check Engine Lamp. The lamp is located on
the instrument panel.
They can also be displayed through the use of the
Diagnostic Readout Box (DRB) scan tool. The DRB
scan tool connects to the data link connector in the
engine compartment (Figs. 45 or 46). For operation of
the DRB, refer to the appropriate Powertrain Diag-
nostic Procedures service manual.
EXAMPLES:
²If the lamp flashes 4 times, pauses and flashes 1
more time, a flashing Diagnostic Trouble Code (DTC)
number 41 is indicated.
²If the lamp flashes 4 times, pauses and flashes 6
more times, a flashing Diagnostic Trouble Code
(DTC) number 46 is indicated.After any stored DTC information has been ob-
served, the display will end with a flashing DTC
number 55. This will indicate the end of all stored
information.
Refer to the Diagnostic Trouble Code (DTC) charts
for DTC identification.
If the problem is repaired or ceases to exist, the
Powertrain Control Module (PCM) cancels the DTC
after 51 engine starts.
Diagnostic Trouble Codes indicate the results of a
failure, but never identify the failed component di-
rectly.
The circuits of the data link connector are shown
in (Fig. 47).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a Diagnostic Trouble Code (DTC).
Refer to the appropriate Powertrain Diagnostic Pro-
cedures service manual for operation of the DRB
scan tool.
Fig. 45 Data Link ConnectorÐYJ ModelsÐTypical
Fig. 46 Data Link ConnectorÐXJ ModelsÐTypical
14 - 50 FUEL SYSTEMJ