Jeep Operations - Snap-on

Chapter 9
Jeep Operations
This chapter explains how to begin using the scan tool’s basic setup and test functions. This
information is specific to Jeep vehicles. For general scan tool functionality, see the user’s
manual appropriate to your diagnostic tool.
For additional information on Jeep vehicles, see the following sections:
• “Jeep Testing” on page 189
• “Chrysler and Jeep Data Parameters” on page 211
• “Jeep Communications Problems” on page 742
T EST SAME VEHICLE AND SYSTEM?
YES
NO
SEL ECT JEEP AND
IDENTIFY THE VEHICL E
SELECT SYSTEM
ENGINE, TRANS, ABS, OR BODY TEST MENUS
SYSTEM TESTS
CODES & DAT A
FUNCTIONAL TESTS
Figure 9-1 Basic Jeep test routine
9.1 Identifying a Vehicle
Many vehicles have an automatic vehicle identification (ID) function. For others, the vehicle
must be manually identified by entering specific vehicle identification number (VIN) characters
into the scan tool.
9.1.1 Manual Identification
The vehicle ID must be entered manually to test the control system on 1990 and earlier
vehicles and may be entered manually for systems that are identified automatically.
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Identifying a Vehicle
NOTE:
Because of midyear manufacturing changes in engine computer systems, you should always
enter a new identification when you test a different vehicle, even when two vehicles are the
same year, model, and have the same engine and accessories installed.
The vehicle ID process begins from the Software Confirmation menu (Figure 9-2).
>CHRYSLER DATABASE (1990-2004)
V 9.0
PRESS Y TO CONTINUE
Figure 9-2 Sample Software Confirmation menu
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To manually ID a vehicle:
1. Press Y to confirm the software selection.
2. Do one of the following:
– 1989 and earlier: Select JEEP (Figure 9-3).
SCROLL TO SELECT A MANUFACTURER
GENERAL MOTORS & SATURN (1980 TO 1999)
CHRYSLER (1983 TO 1999)
>JEEP (1984 TO 1999)
GENERIC OBDII
Figure 9-3 Sample Manufacturer Selection menu
– 1990 and later: Select VEHICLE SYSTEMS (Figure 9-4).
SELECT:
>VEHICLE SYSTEMS
DEMONSTRATION
Figure 9-4 Sample Vehicle ID screen
A vehicle ID request screen similar to Figure 9-5 displays.
SELECT 10TH VIN CHARACTER
VIN: ---------4-----VEHICLE: 2004
FOR AUTOMATIC ID, TURN KEY ON
Figure 9-5 Sample model year request
3. Enter all VIN characters and press Y or N to answer any questions.
When you are finished, a Vehicle ID Confirmation screen displays (Figure 9-6).
VIN: -J--4--1-4-----VEHICLE: 2004 JEEP WRANGLER-RHD
ENGINE: 2.4L L4 MPI
PRESS Y TO CONTINUE. N FOR NEW ID.
Figure 9-6 Sample Vehicle ID Confirmation screen
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4. Press Y if the vehicle ID is correct or press N to identify a different vehicle.
9.1.2 Automatic Identification
Automatic ID is available on 1991 and later Jeep models (Figure 9-7).
CURRENT VEHICLE IDENTIFICATION IS:
VEHICLE: 1997 JEEP XJ(4x4)
A/T
ENGINE: 2.5L L4 MPI
A/C
PRESS Y FOR SAME VEHICLE. N FOR NEW ID
Figure 9-7 Jeep automatic Vehicle ID Confirmation screen
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To automatically identify a vehicle:
1. Attach the test adapter to the data cable.
2. Connect the adapter to the vehicle.
3. Turn the ignition switch on.
4. Select DOMESTIC > JEEP.
The scan tool identifies the vehicle, then displays a vehicle identification screen.
5. Press Y to continue to the SYSTEM SELECTION MENU.
9.1.3 Transmission System Identification
The scan tool automatically identifies the vehicle for all OBD-II models.
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To automatically ID 1991–95 models:
1. Connect the scan tool to the engine diagnostic connector to get vehicle information.
2. Disconnect, and hook up to the transmission diagnostic connector.
After identifying the vehicle, the scan tool displays the System Selection screen.
9.2 Selecting a System
Four control systems are generally available from the System Selection menu (Table 9-1).
Table 9-1 Jeep test availability
CONTROL
SYSTEM
DESCRIPTION
ENGINE
Contains engine control tests from 1984 through the current model year.
TRANS
(Transmission)
Transmission system tests include test programs for AW4, 42RE, 44RE,
45RFE, 46RE, and 545RFE transmissions.
BODY
Body system tests include actuator test mode tests as well as codes and data.
ABS
The ABS tests include test programs for all Jeep vehicles equipped with Bendix
9, and Teves Mark IV, IVg, and MK20 ABS control systems.
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Selecting a System
To select a system:
1. Select an item from the menu (Figure 9-8).
SCROLL TO SELECT A SYSTEM
>ENGINE
TRANS
ABS
Figure 9-8 Sample Jeep SYSTEM SELECTION menu
Selecting any one of these systems from the menu may cause additional vehicle
identification menus to display. For instance, select ENGINE and a vehicle emissions
selection screen often appears (Figure 9-9).
SCROLL TO SELECT A SPECIFIC MODULE
>CALIFORNIA EMISSIONS
FEDERAL EMISSIONS
Figure 9-9 Sample Jeep vehicle emissions selection
2. Select the line that describes the emissions specification on the vehicle emissions control
identification (VECI) sticker.
The next screen is usually the options menu, which describes whether the vehicle has an
automatic or standard transmission, and if it has air conditioning (Figure 9-10).
SCROLL TO SELECT VEHICLE OPTIONS:
>A/T WITH A/C
A/T WITHOUT A/C
M/T WITH A/C
Figure 9-10 Sample Jeep vehicle options selection
3. Select an option.
If TRANS (transmission) is selected from the System Selection menu, the scan tool may
display the message shown in Figure 9-11. If this message displays, return to the System
Selection main menu and select ENGINE.
TRANSMISSION DIAGNOSTIC INFORMATION IS
LOCATED IN THE ENGINE CODES AND DATA
LIST.
PRESS N TO RETURN TO SYSTEM MENU.
Figure 9-11 Transmission data in engine control system message
Additional screens may display depending on the vehicle. All other screens are similar
and require a selection to advance.
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9.3 Connecting to the Vehicle
Once a vehicle has been identified and a system has been selected, a scan tool connection
message is shown, instructing you to use the vehicle test adapters supplied to connect the
scan tool for testing (Figure 9-12).
CONNECT OBD-II K13 ADAPTER TO CONNECTOR
LOCATED UNDER LEFT OF STEERING COLUMN
UNDER DASH.
PRESS Y TO CONTINUE.
Figure 9-12 Sample Jeep connection message
Each test adapter plugs into a specific vehicle diagnostic connector and attaches to one end
of the data cable. The other end of the cable attaches to the scan tool. Captive screws secure
both data cable ends.
The following adapters are available to test Jeep vehicles:
• JEEP-1—(MT2500-49, Figure 9-13) test adapter for 1990 and earlier
• CHRY-1—(MT2500-30, Figure 9-15) engine test adapter for 1991–95; ABS adapter for
1991 model only
• CHRY-2—(MT2500-31, Figure 9-16) transmission and ABS test adapter for 1991–95
models
• OBD-II—(MT2500-46, Figure 9-14) test adapter for 1996 and later
Figure 9-13 MT2500-49 JEEP-1 Adapter
Figure 9-14 MT2500-46 OBD-II adapter with Personality
Key™ device
Figure 9-15 MT2500-30 CHRY-1 adapter
Figure 9-16 MT2500-31 CHRY-2 adapter
The CHRY-1 engine test adapter has a socket for connecting the battery power cable or the
cigarette lighter power cable. A power cable is not required with the JEEP-1, CHRY-2, or the
OBD-II test adapters.
On 1987–90 Jeep models and 1996 and later models, the TCM or PCM communicates
through the same diagnostic connector used for engine testing. On 1991–95 Jeep vehicles,
the TCM communicates through a separate diagnostic connector. The scan tool connects to
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Connecting to the Vehicle
either a 6-pin or 8-pin diagnostic connector, which may be either black or blue in color. Use the
CHRY-2 test adapter to connect to the black or blue connector.
Use Table 9-2 and the following figures to find the correct diagnostic connector location for the
specific vehicle being tested.
Table 9-2 Jeep diagnostic connector locations
SYSTEM
Engine
Transmission
ABS
Body computer
YEAR
ADAPTER
CONNECTOR LOCATION
1984–90
JEEP-1
Under hood (Figure 9-18)
1991–95
CHRY-1
Under hood (Figure 9-19)
1996–later
OBD-II
Under driver-side dash (Figure 9-17)
1987–90
JEEP-1
Under hood. For Cherokee and
Comanche, see Figure 9-18.
1991–95
CHRY-2
Under dash
1996–later
OBD-II
Under driver-side dash (Figure 9-17)
1989–90
JEEP-1
Under hood (Figure 9-18)
1991
CHRY-1
Under hood
1992–95
CHRY-2
Under dash
1996–later
OBD-II
Under driver-side dash (Figure 9-17)
1996–later
OBD-II
Under driver-side dash (Figure 9-17)
Figure 9-17 1996 and later OBD-II DLC
Figure 9-18 1990 and earlier DLC (left)—use JEEP-1 adapter (right)
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Figure 9-19 1991–95 CHRY-1 DLC (left)—use CHRY-2 adapter (right)
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To connect the scan tool to the test vehicle:
1. Be sure the ignition switch is off.
2. Follow the on-screen instructions and connect the scan tool data cable to the test vehicle.
a. Select the proper test adapter and attach it to the data cable.
b. Connect the other end of the data cable to the scan tool data port.
c. Connect the test adapter to the vehicle.
Test adapters fit into the connectors only one way. Be sure the connector is installed
securely.
3. Switch the ignition on.
4. Press Y to continue.
The main menu for the selected system displays, and the scan tool is connected to the
data stream.
9.4 Jeep Vehicles Without Self-Diagnostic Capability
The Jeep vehicles listed below either do not have electronic engine control systems, or they
have systems without self-diagnostic capabilities. They will not communicate with a scan tool
or MT2500 scan tool programs are not available.
Table 9-3 Jeep vehicles without self-diagnostic capability
YEAR
MODELS
Pre–1984
All models
1984–86
2.8L carbureted, except with California emissions
Pre–1992
Jeep Grand Wagoneer
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Jeep Vehicles Without Self-Diagnostic Capability