Vehicle Maintenance Monitor - Operation/Diagnosis
9217amcjeep01
NO.: 08-08-90
DATE: March 26,1990
GROUP: INSTRUMENT PANEL
MODELS: 1990 Premier/Monaco Service Manual
VEHICLE MAINTENANCE MONITOR (VMM)
GENERAL INFORMATION
Fuse 2 applies voltage to the vehicle maintenance monitor at all times. This allows the monitor to remember the vehicle's present status when ignition is OFF. Fuse 8 applies voltage to the vehicle maintenance monitor to turn on the LCD display and begin monitoring the inputs to obtain information.
The conditions monitored are the brake and taillight bulbs, coolant level, windshield washer fluid level, the vehicle speed and the door ajar inputs. The monitor also receives signals from the lamp outage module. If the vehicle is started and no conditions are present, "monitor" will be displayed. Otherwise one of the 9 monitored system messages or one of the 6 service reminder messages is displayed. If the VMM detects more than one condition it will list the highest priority message first. It will then cycle through a list of all existing faults, and return to the abbreviated message for the highest priority fault. All available VMM messages and their abbreviations are listed in order of priority as follows:
Door Ajar (DOOR) -
The appropriate door(s) is illuminated on the vehicle outline. Close door(s) to reset.
Brake Lamp Out (LAMP) -
Is activated when the brakes are applied and a bulb is burned out. To reset. replace bulb.
Tail Lamp Out (LAMP) -
Is activated when the tail lamps are on and a bulb is burned out. To reset, replace bulb.
Coolant Fluid Low (COOLANT) -
Add engine coolant as required to reset.
Washer Fluid Low (WASHER) -
Add windshield washer fluid as required to reset.
Service Transmission (TRANS) -
Indicates fault in the automatic transmission of 4 cylinder vehicles.
Perform Service (SERVICE) -
Is activated at 7,500 miles (12000 kms) intervals to indicate that regular service and maintenance is due. Perform required service then press RESET button until the sound of the beep to clear the display.
Coolant Sensor Fault (SENSOR) -
See diagnostics.
Washer Sensor Fault (SENSOR) -
See diagnostics.
Miles (KMS) To Service -
Indicates distance to the next scheduled service.
When a condition is present, the monitor also sends a signal to the chime module. The vehicle maintenance monitor uses the vehicle speed input to calculate the distance traveled. It automatically notifies the driver, after a pre-programmed number of miles has elapsed, to perform a particular service on the vehicle. When the lamps are on, the vehicle maintenance monitor display intensity is adjustable by using the panel dimmer switch. The monitor receives a signal from the English/Metric switch to display either English or Metric measurements. The vehicle maintenance monitor also has a self-diagnostics. The vehicle maintenance monitor checks the monitor, the sensors and their circuits without the use of any special tools.
SELF-DIAGNOSTICS
To enter the automatic diagnostics mode, make sure the system is in the English mode, simultaneously press and hold the CHECK and LIST switches then turn the ignition switch to RUN. With these switches pressed, move the ignition key to the ON position. The diagnostic program will start and loop continuously. To exit the diagnostic mode, simultaneously press the CHECK and LIST switches.
There are two modes for the diagnostic program: automatic and manual. In the automatic mode, the program will automatically perform tests in sequence. The sequence of tests will repeat until the diagnostic routine is exited. In the manual mode, each test will be performed individually and will only progress to the next test when the CHECK switch is pressed. Modes can be changed by pressing the English/Metric switch. If the instrument cluster is in the English mode, the program is in the automatic mode. If in the Metric mode, the program is in the manual mode.
NOTE:
To reset on intermittent fault. (I.F.) Progress through the test sequence in the MANUAL mode until the fault is displayed. Then press the reset button.
DISPLAYS INCORRECT OR DOES NOT OPERATE
COMPUTER SCHEMATIC
SELF-DIAGNOSTICS
The only way to enter the self-diagnostic mode is done by turning the ignition switch to RUN while the trip/time and reset switches are simultaneously depressed. The self-diagnostics consists of five tests. When the self-diagnostics start, the trip computer starts with Test 1. The sequence of tests after that depends on which switch is depressed.
^ Depressing the trip/time switch initiates Test 2 when the English/Metric switch is in the ENGLISH position.
^ Depressing the trip/time switch initiates Test 3 when the English/Metric switch is in the METRIC position.
^ Depressing the fuel/temp switch initiates Test 4 when the English/Metric switch is in the ENGLISH position.
^ Depressing the fuel/temp switch initiates Test 5 when the English/Metric switch is in the METRIC position.
^ Switching the key off exits self-diagnostics without resetting any fault conditions.
^ Depressing the reset switch returns the trip computer to the time display and resets any fault conditions.
Test 1
The trip computer displays software revision level (there are three revision levels). Then the fuel tank size. The chart lists codes that will be displayed for various tank sizes. The Premier, 17 gallon tank is represented by tank code number 4.
NOTE:
If the trip computer displays an ERR during test 1, replace the trip computer.
With version 2 software, every segment in the display is illuminated and extinguished. Segment testing continues until the trip/time button is pressed, the fuel/temp button is pressed, or the self-diagnostics mode is exited. With version 3 software the previous display test is not performed. Version 3 maintains the display of software revision level and tank size code until trip/time or fuel/temp is pressed or until exit from self-diagnostics.
Tests 2 and 3 Tests 2 and 3 check the circuit of the exterior temperature sensor and the speed input circuit. TEST 2 (English Metric switch set on ENGLISH)
^ The Temp telltale lights.
^ If a failure of the ambient air temperature sensor input is detected the display is "CO" for an open in the circuit, or "CS" for a short in the circuit.
^ If no failure is detected, the instantaneous temperature will be displayed. TEST 3 (English Metric switch set on METRIC)
^ The Average Speed telltale lights.
^ The speed sensor frequency is displayed.
^ This frequency begins at 0 and increase as the vehicle speed increases.
Tests 4 and 5 Tests 4 and 5 check the fuel level circuit and fuel now circuit. TEST 4 (English Metric switch set on ENGLISH)
^ The Range telltale lights.
^ If a failure of the fuel level sensor input is detected the display is "CO" for an open in the circuit, or "CS" if there is a short in the circuit.
^ If no failures are detected, the fuel level will be displayed in liters. TEST 5 (English/Metric switch set on METRIC)
^ The Instant Economy telltale lights.
^ If a failure of the flow input is detected the display will be "CO"
^ If a failure is not detected, the frequency of the fuel flow sensor will be displayed. This frequency will vary as the fuel consumption varies.