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OPERATION - DATA BUS COMMUNICATION The PCM uses the SCI communication bus to pre- form engine diagnostics and flash operations. The OPERATION - IGNITION SENSE - PCM INPUT The ignition sense input informs the Powertrain Control Module (PCM) that the ignition switch is in OPERATION - PCM GROUND Ground is provided through multiple pins of the PCM connector. Depending on the vehicle there may The power grounds are used to control the ground side relays, solenoids, ignition coil or injectors. The The PCM case is shielded to prevent RFI and EMI. The PCM case is grounded and must be firmly Internally all grounds are connected together, how- ever there is noise suppression on the sensor ground. OPERATION OPERATION The PCM receives input signals from various switches and sensors that are referred to as PCM NOTE: PCM Inputs: • Air Conditioning Controls • Ambient Air temperature Sensor • ASD Sense • Baro/Tip (Turbo) • Battery Voltage • Battery Temperature Sensor • Brake Switch • Camshaft Position Sensor • Clutch Upstop Switch • Clutch Interlock • Crankshaft Position Sensor • Engine Coolant Temperature Sensor • Fuel Level Sensor (Bus message) • Ignition Switch • Intake Air Temperature Sensor • J1850 • Knock Sensor (2.0, 2.4L) • Natural Vacuum Leak Detection (NVLD) • Manifold Absolute Pressure (MAP) Sensor • Oil Pressure Switch • Oxygen Sensors • Power Steering Pressure Switch • SCI Receive • Speed Control Switches • Throttle Position Sensor • Transmission Control Relay (Switched B+) • Transmission Input Shaft Speed Sensor • Transmission Output Shaft Speed Sensor • Transmission Pressure Switches (L/R, 2/4, OD) • Transmission Range Sensor (TRS) • Transmission Oil Temperature Sensor (Integral to TRS) • Vehicle Speed Sensor (MTX-equipped models) NOTE: PCM Outputs: • Air Conditioning Clutch Relay • Auto Shutdown (ASD) Relay • Charging Indicator Lamp (Bus Message) • SCI Transmit • Proportional Purge Solenoid • EGR Solenoid • Fuel Injectors • Fuel Pump Relay • Generator Field • Idle Air Control Motor (2.0/2.4L) • Ignition Coils Fig. 5 PCM 8E - 6 ELECTRONIC CONTROL MODULES PL/SRT-4 POWERTRAIN CONTROL MODULE (Continued) |