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 TEST SAME VEHICLE AND SYSTEM? YES NO SELECT JEEP AND IDENTIFY THE VEHICLE SELECT SYSTEM ENGINE, TRANS, ABS, OR BODY TEST MENUS SYSTEM TESTS CODES & DATA 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. 181
Chapter 9 Jeep Identifying a Vehicle NOTE: i 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 z 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 182
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 z 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. z 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 ENGINE TRANS (Transmission) BODY ABS DESCRIPTION Contains engine control tests from 1984 through the current model year. Transmission system tests include test programs for AW4, 42RE, 44RE, 45RFE, 46RE, and 545RFE transmissions. Body system tests include actuator test mode tests as well as codes and data. The ABS tests include test programs for all Jeep vehicles equipped with Bendix 9, and Teves Mark IV, IVg, and MK20 ABS control systems. 183
Chapter 9 Jeep Selecting a System z 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. 184
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 185
Chapter 9 Jeep 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 YEAR ADAPTER CONNECTOR LOCATION 1984 90 JEEP-1 Under hood (Figure 9-18) Engine 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. Transmission 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) ABS 1991 CHRY-1 Under hood 1992 95 CHRY-2 Under dash 1996 later OBD-II Under driver-side dash (Figure 9-17) Body computer 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) 186
Figure 9-19 1991 95 CHRY-1 DLC (left) use CHRY-2 adapter (right) z 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 187
Chapter 9 Jeep Jeep Vehicles Without Self-Diagnostic Capability 188