Understanding Computer Control Systems Electrical 2 Understanding Computer
- Slides: 22
Understanding Computer Control Systems Electrical 2
Understanding Computer Control Systems �Processing system �Input Sensors � Switches � Data bus CAN or OBD � �Processing � Electronic Control Module (ECM) � Parameters, setting and programming �Output � Solenoids � Data bus CAN or OBD � MIL lights � Motors or Actuators
Understanding Computer Control Systems �Switches �Key �Cruise On off � Set resume � �Retarder � On off � Level �Brake � Service (some systems will utilize 2) � Park �Switches �Interlock �PTO �Door �Throtle �Idle Validation Switch (IVS)
Understanding Computer Control Systems �Temperature �Thermistor �Thermocouple �Negative Temperature Coefficient (NTC) �Positive Temperature Coefficient (PTC) �Two wire � Passive sensor �Three wire � Active sensor �Used for � Water temp � Oil temp � Air temp Ambiant � Manifold � � EGR Pre cooler � Post cooler � Fuel temp � Cabin temp �
Understanding Computer Control Systems �Pressure (piezo) �Piezoresistive � �Used for � Oil pressure Engine lube � HEUI action � Hydraulic � Standard on Detroit, Caterpillar, and Volvo. Mack �Piezoelectric � Standard on Cummins and some heavy equipment � You. Tube on Piezoelectric �Mechanical � Older electrical gauges � Fuel pressure Primary � Secondary � � Air Pressure Manifold � Atmospheric �
Understanding Computer Control Systems �Speed and position �Permanent magnet � Hall effect �Potentiometer �Used for � Wheel speed � Crankshaft � Camshaft � Fuel pump � Actuators � Vehicle speed � Throttle � Accessories
Understanding Computer Control Systems �Databus �Automotive � OBD I � Vehicle manufacture sets standard � OBD II � Current �Heavy duty � CAN � J 1587 or J 1787 � J 1939 or J 1922 �Proprietary link
J 1587
J 1939
Connectors
Understanding Computer Control Systems �Processor �Electronic Control Module (ECM) �Programming and Parameters �Settings �ECM used on �SRS �ABS/ATC �Engine �Transmission �Dashboards �Power trains
Understanding Computer Control Systems �Solenoids �Actuators for Injection � Retarder oil flow � Pneumatic fans � Hydraulics � Starting aids � EGR � Intake Valve Actuators or Variable Valve Actuators �
Understanding Computer Control Systems �Malfunction Indicator Lamp �MIL �Shutdown Engine Lamp �SEL �Check Engine Lamp �CEL �Antilock Brakes �ABS �Automatic traction Control �ATC �Transmission �Automated �Automatic
Understanding Computer Control Systems �Motors/Actuators �Electronic over Mechanical pumps �Emissions � EGR �Variable Nozzle Turbo � VNT �Variable Geometry Turbo � VGT
Understanding Computer Control Systems �Diagnostic Trouble Codes �DTC �Flash codes or proprietary codes �SAE codes �Message Identifier � MID �Parameter Identifier � PID �System Identifier � SID �Component Identifier � CID �Utilizes only one of the following PID, SID, or CID �Failure mode Identifier �Active �Currently occurring �Can not be cleared �Historic �Is a record of a code �Can normally be cleared some require a password
Understanding Computer Control Systems � Examples of Common SAE J 1708 Message Identification - MID 128 Engine � MID 130 Transmission � MID 136 Brakes, Power Unit - ABS MID 140 Instrument Cluster � MID 144 Cruise Control / Vehicle Control Unit � MID 146 Cab Climate Control � MID 150 Suspenstion, Power Unit MID 166 Tires, Power Unit � MID 177 Particulate Trap System � MID 181 Communication Unit, Satellite � MID 200 Auxillary Cab Climate Control MID 216 Light Control Administrator Unit � MID 232 Safety Restraint System � MID 249 Body Controller � Examples of Common SAE 1708 Parameter Identification - PID 8 Brake system air pressure Low warning switch statuts � PID 12 Brake Stroke Status � PID 27 Percent Exhaust Gas Recirculation Valve #1 Postision � PID 51 Throttle Postion PID 80 Washer Fluid Level � PID 81 Particulate Trap Inlet Pressure � PID 84 Road Speed � PID 91 Percent Accelerator Pedal Position � PID 94 Fuel Delivery Pressure � PID 97 Water In Fuel Indicator � PID 98 Engine Oil Level f
Understanding Computer Control Systems � Examples of Common SAE J 1708 Subsystem Identification - SID � SID 213 PLC Data Link � SID 231 SAE J 1939 Data Link � SID 232 5 Volts DC Supply � SID 250 SAE J 1708/J 1587 Data Link � SID 251 Power Supply � Examples of Common SAE J 1708 Failure Mode Identifiers - FMI � FMI 0 Data Valid but above normal operational range � FMI 1 Data Valid but below normal operational range � FMI 2 Data Erratic � FMI 3 Voltage above normal - Shorted High � FMI 4 Voltage below normal - Shorted Low � FMI 5 Current below normal - Open Circuit � FMI 6 Current above normal - Grounded Circuit � FMI 7 Mechanical System Fault � FMI 8 Abnormal Frequency � FMI 9 Abnormal Update Rate � FMI 10 Abnormal Rate of Change � FMI 11 Failure Mode not Identified � FMI 12 Bad Device � FMI 13 Out of Calibration � FMI 14 Special Instructions
Understanding Computer Control Systems �Reading codes �Flash Codes � Utilizes equipment Switches � Lights � � Different procedure for different equipment Dedicated switches � Other switches � �Diagnostic Data Reader � OEM specific � Generic �Personal computer �Generic �OEM Insite � Electronic Technician � Detroit Diagnostic Data Link �
Understanding Computer Control Systems �Strategy Based Diagnostics (SBD) �Verify customer complaint �Quick check vehicle �Check DTC and history �Check TSB’s �Follow the service manual troubleshooting �Analyze and record DTCs �Clear codes �Recheck DTCs �Determine course of action
Understanding Computer Control Systems �Return
Understanding Computer Control Systems �Return
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