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perature, throttle position, transmission gear selec- The PCM adjusts idle speed based on inputs it receives from sensors that react to: throttle position, Based on inputs that it receives, the PCM adjusts ignition coil dwell. The PCM also adjusts the gener- NOTE: PCM Inputs: • A/C request (if equipped with factory A/C) • A/C select (if equipped with factory A/C) • Auto shutdown (ASD) sense • Battery temperature • Battery voltage • Brake switch • CCD bus (+) circuits • CCD bus (-) circuits • Camshaft position sensor signal • Crankshaft position sensor • Data link connection for DRB scan tool • Engine coolant temperature sensor • Extended idle switch (4.0L engine with police package) • Fuel level • Generator (battery voltage) output • Ignition circuit sense (ignition switch in on/off/ crank/run position) • Intake manifold air temperature sensor • Leak detection pump (switch) sense (if equipped) • Manifold absolute pressure (MAP) sensor • Oil pressure • Oxygen sensors • Park/neutral switch (auto. trans. only) • Power ground • Power steering pressure switch (2.5L engine only) • Sensor return • Signal ground • Speed control multiplexed single wire input • Throttle position sensor • Vehicle speed sensor NOTE: PCM Outputs: • A/C clutch relay • Auto shutdown (ASD) relay • CCD bus (+/-) circuits for: speedometer, voltme- ter, fuel gauge, oil pressure gauge/lamp, engine temp. • Data link connection for DRB scan tool • EGR valve control solenoid (if equipped) • EVAP canister purge solenoid • Five volt sensor supply (primary) • Five volt sensor supply (secondary) • Fuel injectors • Fuel pump relay • Generator field driver (-) • Generator field driver (+) • Idle air control (IAC) motor • Ignition coil • Leak detection pump (if equipped) • Malfunction indicator lamp (Check engine lamp). Driven through CCD circuits. • Radiator cooling fan relay • Speed control vacuum solenoid • Speed control vent solenoid • Tachometer (if equipped). Driven through CCD circuits. • Transmission convertor clutch circuit MODES OF OPERATION OPERATION As input signals to the Powertrain Control Module (PCM) change, the PCM adjusts its response to the The PCM will operate in two different modes: Open Loop and Closed Loop. During Open Loop modes, the PCM receives input signals and responds only according to preset PCM During Closed Loop modes, the PCM will monitor the oxygen (O2S) sensors input. This input indicates Fig. 1 PCM Location 1 – (3) 32–WAY CONNECTORS 14 - 26 FUEL SYSTEM XJ DESCRIPTION AND OPERATION (Continued) |