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The battery input also provides the voltage that is needed to keep the PCM memory alive. The memory SENSOR RETURN—ECM/PCM INPUT (ANALOG DESCRIPTION Sensor Return provides a low noise Analog ground reference for all system sensors. IGNITION CIRCUIT SENSE—ECM/PCM INPUT DESCRIPTION The ignition circuit sense input signals the ECM and PCM that the ignition (key) switch has been IGNITION CIRCUIT SENSE—PCM INPUT The ignition circuit sense input signals the PCM that the ignition (key) switch has been turned to the POWER GROUND DESCRIPTION Provides a common ground for power devices (sole- noid and relay devices). NEEDLE MOVEMENT OR INTRUMENTED FIRST DESCRIPTION This input from the ECM supplies a constant 30 mA electrical current source for the first injector sen- The first injector sensor is a magnetic (inductive) type. The first injector sensor is used only on the fuel injector for the number–1 cylinder (Fig. 4). It is not FUEL INJECTOR SENSOR—GROUND DESCRIPTION Provides a low noise ground for the fuel injector sensor only. ENGINE COOLANT TEMPERATURE SENSOR— DESCRIPTION The 0–5 volt input from this sensor tells the ECM and PCM the temperature of the engine coolant. The sensor is located on the side of the #3 cylinder head near the rear of fuel injection pump (Fig. 5). ENGINE SPEED SENSOR—ECM INPUT DESCRIPTION The engine speed sensor is mounted to the trans- mission bellhousing at the left/rear side of the engine The engine speed sensor produces its own output signal. If this signal is not received, the ECM will not The engine speed sensor input is used in conjunc- tion with the first injector sensor to establish fuel Fig. 4 Fuel Injector Sensor 1 – NEEDLE MOVEMENT SENSOR 14 - 26 FUEL SYSTEM—2.5L DIESEL ENGINE XJ DESCRIPTION AND OPERATION (Continued) 2000 JEEP CHEROKEE |