Jeep XJ. Manual - part 812

SYMPTOM

DIAGNOSTIC TEST

HARD START

CHECKING THE FUEL PRESSURE
CHECKING COOLANT SENSOR CALIBRATION
CHECKING THROTTLE POSITION SENSOR CALIBRATION
CHECKING MAP SENSOR CALIBRATION
CHECKING THE MINIMUM IDLE AIR FLOW
CHECKING IDLE AIR CONTROL MOTOR OPERATION
CHECKING EVAP EMISSION SYSTEM
CHECKING IAT SENSOR

START AND STALL

CHECKING PCM POWER AND GND CKT
CHECKING THE FUEL PRESSURE
CHECKING COOLANT SENSOR CALIBRATION
CHECKING THROTTLE POSITION SENSOR CALIBRATION
CHECKING MAP SENSOR CALIBRATION
CHECKING THE MINIMUM IDLE AIR FLOW
CHECKING IDLE AIR CONTROL MOTOR OPERATION

HESITATION/SAG/STUMBLE

ENGINE STALLS IN GEAR

CHECK TCC OPERATION

SURGE

LACK OF POWER/SLUGGISH

GENERAL INFORMATION

SYMPTOM

DIAGNOSTIC TEST

SPARK KNOCK/DETONATION

CUTS OUT/MISSES

CHECKING PCM POWER AND GND CKT
CHECKING THE FUEL PRESSURE
CHECKING THE MINIMUM IDLE AIR FLOW
CHECKING IDLE AIR CONTROL MOTOR OPERATION

BACKFIRE/POPBACK

CHECKING PCM POWER AND GND CKT
CHECKING THE FUEL PRESSURE
CHECKING MAP SENSOR CALIBRATION
CHECKING THE MINIMUM IDLE AIR FLOW

RUNS ROUGH/UNSTABLE/
ERRATIC IDLE

POOR FUEL ECONOMY

GENERAL INFORMATION

3.3.5

NO START INFORMATION

IMPORTANT NOTE:

If the Powertrain Control Module has been

changed and the correct VIN and mileage have not
been programmed, a DTC will be set in the ABS and
Air bag modules. In addition, if the vehicle is
equipped with a Sentry Key Immobilizer Module
(SKIM), Secret Key data must be updated to enable
starting.

FOR ABS AND AIR BAG SYSTEMS:

1. Enter correct VIN and Mileage in PCM.

2. Erase DTC’s in ABS and Air Bag modules.

FOR SKIM THEFT ALARM:

1. Connect the DRBIII

t to the data link connector.

2. Go to Theft Alarm, SKIM, Misc. and place the

SKIM in secured access mode, by using the
appropriate PIN code for this vehicle.

3. Select Update the Secret Key data, data will be

transferred from the SKIM to the PCM (This is
required to allow the vehicle to start with the
new PCM).

4. If three attempts are made to enter secured

access mode using the incorrect PIN, secured
access mode will be locked out for one hour. To
exit this lock out mode, leave the ignition key in
the Run/Start position for one hour. Ensure all
accessories are turned off. Also monitor the bat-
tery state and connect a battery charger if nec-
essary.

3.4

USING THE DRBIII

Refer to the DRBIII

t user’s guide for instructions

and assistance with reading DTC’s, erasing DTC’s,
and other DRBIII

t functions.

3.5

DRBIII

T ERROR MESSAGES AND

BLANK SCREEN

Under normal operation, the DRBIII

t will dis-

play one of only two error messages:

– User-Requested WARM Boot by pressing

MORE and NO at the same time.

ver: 2.29
date: 1 Oct93
file: key_itf.cc
date: Jan 12 1994
line: 544
err: 0x1
User-Requested WARM Boot

Press MORE to switch between this display

and the application screen.

Press F4 when done noting information.

or User-Requested COLD Boot by pressing

MORE and YES at the same time.

ver: 2.29
date: 1 Oct99
file: key_hndi.cc
date: Mar 8 2000
line: 1297
err: 0x1
User-Requested COLD Boot

Press MORE to switch between this display

and the application screen.

Press F4 when done noting information.

3.5.1

DRBIII

T DOES NOT POWER UP

If the LED’s do not light or no sound is emitted at

start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
connector cavity 16). Check for proper ground con-
nection at DLC cavity 4. A minimum of 11 volts is
required to adequately power the DRBIII

If all connections are proper between the

DRBIII

t and the vehicle or other devices, and the

vehicle battery is fully charged, and inoperative
DRBIII

t may be the result of faulty cable or vehicle

wiring. For a blank screen, refer to the appropriate
body diagnostics manual.

3.5.2

DISPLAY IS NOT VISIBLE

Low temperatures will affect the visibility of the

display. Adjust the contrast to compensate for this
condition

GENERAL INFORMATION

4.0

DISCLAIMERS, SAFETY,
WARNINGS

4.1

DISCLAIMERS

All information, illustrations, and specifications

contained in this manual are based on the latest
information available at the time of publication.
The right is reserved to make changes at any time
without notice.

4.2

SAFETY

4.2.1

TECHNICIAN SAFETY INFORMATION

WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.

Set the parking brake and block the wheels before

testing or repairing the vehicle. It is especially
important to block the wheels on front-wheel drive
vehicles; the parking brake does not hold the drive
wheels.

When servicing a vehicle, always wear eye pro-

tection, and remove any metal jewelry such as
watchbands or bracelets that might make an inad-
vertent electrical contact.

When diagnosing a powertrain system problem,

it is important to follow approved procedures where
applicable. These procedures can be found in ser-
vice manual procedures. Following these proce-
dures is very important to the safety of individuals
performing diagnostic tests.

4.2.2

VEHICLE PREPARATION FOR
TESTING

Make sure the vehicle being tested has a fully

charged battery. If it does not, false diagnostic codes
or error messages may occur.

4.2.3

SERVICING SUB ASSEMBLIES

Some components of the powertrain system are

intended to be serviced in assembly only. Attempt-
ing to remove or repair certain system sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.

4.2.4

DRBIII

T SAFETY INFORMATION

WARNING: EXCEEDING THE LIMITS OF THE
DRB MULTIMETER IS DANGEROUS. IT CAN
EXPOSE

YOU

SERIOUS

INJURY.

CAREFULLY READ AND UNDERSTAND THE
CAUTIONS

AND

THE

SPECIFICATION

LIMITS.

Follow the vehicle manufacturer’s service specifi-

cations at all times.

•

Do not use the DRBIII

t if it has been damaged.

•

Do not use the test leads if the insulation is
damaged or if metal is exposed.

•

To avoid electrical shock, do not touch the test
leads, tips, or the circuit being tested.

•

Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.

GENERAL INFORMATION

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