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The PCM adjusts ignition timing based on the fol- lowing inputs. • Coolant temperature • Intake air temperature • Engine speed (crankshaft position sensor) • Manifold absolute pressure • Throttle position the idle air control motor based on the following • Air conditioning sense • Battery voltage • Coolant temperature • Engine speed (crankshaft position sensor) • Engine run time • Manifold absolute pressure • Throttle position • Vehicle distance (speed) are mounted externally, but turned on and off by the The crankshaft position sensor signal is sent to the PCM. If the PCM does not receive the signal within The PCM contains a voltage converter that changes battery voltage to a regulated 5 volts direct OPERATION - 5 VOLT SUPPLY - PCM OUTPUT The PCM supplies 5 volts to the following sensors: • Ambient Temperature sensor • Battery Temperature • Camshaft Position Sensor (NGC) • Crankshaft Position Sensor (NGC) • Engine Coolant Temperature sensor • Inlet Air Temperature Sensor • Manifold Absolute Pressure Sensor • Oil Pressure Sensor • Throttle Position Sensor STANDARD PROCEDURE - OBTAINING BULB CHECK Key on: Bulb illuminated until vehicle starts, as long as all once per trip (readiness) monitors com- pleted. If monitors have not been completed, then: OBTAINING DTC’S USING DRB SCAN TOOL (1) Connect the DRBIII t scan tool to the data link (diagnostic) connector. This connector is located in (2) Turn the ignition switch on and access the “Read Fault” screen. (3) Record all the DTC’s and “freeze frame” infor- mation shown on the DRB scan tool. (4) To erase DTC’s, use the “Erase Trouble Code” data screen on the DRB scan tool. Do not erase any REMOVAL If the PCM is replaced of usage, update the mile- age and vehicle identification number (VIN) in the t scan tool to change the mileage and VIN in the PCM. If this step is not done t scan tool. To avoid possible voltage spike damage to PCM, ignition key must be off, and the negative battery The Powertrain Control Module Location (Fig. 4). Fig. 4 PCM LOCATION 8E - 6 ELECTRONIC CONTROL MODULES ZB POWERTRAIN CONTROL MODULE (Continued) |