How to Enter Service Mode
HOW TO ENTER SERVICE MODE
To enter diagnostic mode, proceed as follows:
1. Turn the ignition "ON".
2. Touch the "OFF" and "WARMER" pads on the CRT's Climate Control page simultaneously and hold until a double "Beep" is heard or you see a page entitled "Service Mode".
NOTICE: Operating the vehicle in the "Service Mode" for extended time periods without the engine running or without a battery charger will cause the battery to run down and possibly relate false diagnostic information, or cause a no start condition. To ensure proper operation, attach a battery charger on "Trickle" charge if vehicle is to be operated in "Service Mode" without engine running for periods longer than 1/2 hour.
Trouble Code Display
After "Service Mode" is entered any "trouble Codes" stored in computer memory will be displayed. ECM codes will be displayed first. If no ECM trouble codes are stored, the CRT will display a "NO ECM CODES" message for approximately two seconds. All ECM codes will be prefixed with an "E" (i.e. EO13, E014, etc.). For the ECM code assignments. The lowest numbered ECM code will be displayed first followed by progressively higher numbered codes present. Codes will be displayed consecutively for two second intervals until the highest code present has been displayed. When all ECM codes have been displayed, BCM codes will be displayed. Following the highest ECM code present or the "NO ECM CODES" message the lowest numbered ECM code will be displayed for approximately two seconds. BCM codes displayed will also be accompanied by "Current" or "History". "History" indicates the failure was not present the last time the code was tested and "Current" indicates the fault still exists. Since the ECM is not capable of making this determination these messages do not appear when ECM codes are being displayed. All BCM codes will be prefixed with a "B" (i.e. B110, etc.). Progressively higher numbered BCM codes, if present, will be displayed consecutively for two second intervals until the highest code present has been displayed. If no BCM Trouble Codes are stored "NO ECM CODES" message will be displayed. At any time during the display of ECM or BCM codes, if the "NO" pad is touched, the display of codes will be bypassed. At any time during the display of trouble codes, if the "Exit" pad is touched the CRT will exit "Service Mode" and go back to normal vehicle operation.
Climate Control In Service Mode
Upon entering the "Service Mode", the climate control will operate in whatever setting was being commanded just prior to depressing the "OFF" and "WARM" pads. Even though the display may change just as the pads are touched, the prior operating setting is remembered and will resume after Service Mode is entered. During "Service Mode" the climate control can be operated the same as normally by touching the climate control border pad and calling up the climate control page. To get back to "Service Mode" page, simply touch the border pad marked diagnostics. This will take you back to the exact same spot you were at in "Service Mode" before you touched the climate control border pad. The climate control and diagnostic border pads are~ the only two border pads that will operate while' in "Service Mode".
How to Operate "Service Mode"
After trouble codes have been displayed, the "Service Mode" can be used to perform several tests on different systems one at a time. Upon completion of code display, a specific system may be selected for testing or a segment check can be performed (see "IPC Segment Check").
A. Selecting the System
Following the display of trouble codes, the first available system will be displayed (i.e. ECM). While selecting a system to test, any of the following actions may be taken to control the display:
1. Touching the "EXIT" pad will stop the system selection process and return the display to the beginning of the trouble code sequence.
2. Touching the "NO" pad will display the next available system selection. This allows the display to be stepped through all system choices. This list of systems can be repeated following the display of the last system.
3. Touching the "YES" pad will select the displayed system for testing. At this point the first available test type will appear with the selected system name above it.
B. Selecting the Test Type
Having selected a system, the first available test type will be displayed (i.e. ECM DATA ). While selecting a specific test type, any of the following actions may be taken to control the display:
1. Touching the "EXIT" pad will stop the test type selection process and return the display to the next available system selection.
2. Touching the "NO" pad will display the next available test type for the selected system. This allows the display to be stepped through all available test type choices. This list of test types can he repeated following the display of the last test type.
3. Touching the "YES" pad will select the displayed test type. At this point the display will either indicate that the selected test type is in progress or the first of several specific tests will appear. (If "NO DEVICES" is displayed, no tests are available).
C. Selecting the Test
Selection of the "DATA", "INPUTS?", "OUTPUTS?" or "OVERRIDE?" test types will result in the first available test being displayed. If a "Select ERR" message ever appears this test is not allowed with the engine running. Turn the engine off and try again. Four characters of the display will contain a test code to identify the selection. The first two characters are letters which identify the system and test type (i.e. ED for ECM DATA) and the last two characters numerically identify the test (i.e ED01 for Throttle Position). While selecting a specific test, any of the following actions may be taken to control the display:
1. Touching the "EXIT" pad will stop the test selection process and return the display to the next available test type for the selected system.
2. Touching the "NO" pad will display the next smaller test number for the selected test type. If this pad is touched with the lowest test number displayed, the highest test number will then appear.
3. Touching the "YES" pad will display the next larger test number for the selected test type. If this pad is touched with the highest test number displayed, the lowest test number will then appear.
D. Selecting "CODE RESET?"
Selection of the "CODE RESET?" test type will result in the message "CODES CLEAR" being displayed with the selected system name above it after the "yes" pad has been touched. This message will appear for 3 seconds to indicate that all stored trouble codes have been erased from that system's memory. After 3 seconds the display will automatically return to the next available test type for the selected system.
E. IPC Segment check
Whenever the key is on and the vehicle is in Park, pressing the "TEST" button on the IPC will cause the IPC to sequentially illuminate and blank all segments and telltales in the cluster. This is helpful in determining if any bulbs or segments of the cluster's vacuum florescent display are out, or always on. To give the technician more time to study the various segments, whenever in the "Service Mode" and not in the middle of running a test, such as when the CRT displays "ECM?", if the "TEST" button on the IPC is depressed the segment check will run 10 times slower than when not in "Service Mode".
F. How to Exit "Service Mode"
To get out of the service mode, repeatedly touch the "EXIT" pad until the "Service Mode" page disappears or turn the ignition switch off. Trouble codes are not erased when this is done.