1994 B350 1 Ton Van V8-360 59L Powertrain Control Module Overview
Engine Start-Up
This is an OPEN LOOP mode.
When the starter motor is engaged, the Powertrain Control Module (PCM) receives input from:
^ Battery voltage
^ Crankshaft position (CKP) sensor
^ Engine coolant temperature (ECT) sensor
^ Intake air temperature (IAT) sensor
^ Throttle position sensor (TPS)
^ Camshaft position (CMP) sensor
^ Starter relay
Based on these inputs, the PCM will:
^ Monitor crankshaft position sensor. If no signal is received within 3 seconds, the PCM will shut down the fuel injection system.
^ Supply the injectors with a ground path, firing all injectors until the PCM determines crankshaft position.
^ Determine proper ignition timing.
Engine Warm-Up
This is an OPEN LOOP mode.
During engine warm-up, the Powertrain Control Module (PCM) receives input from:
^ Battery voltage
^ Crankshaft position (CKP) sensor
^ Engine coolant temperature (ECT) sensor
^ Intake air temperature (IAT) sensor
^ Manifold absolute pressure (MAP) sensor
^ Throttle position sensor (TPS)
^ Camshaft position (CMP) sensor
^ A/C select switch
Based on these inputs the PCM will:
^ Apply voltage to the injectors. The PCM then controls injection sequence and pulse width by switching individual injector ground paths on
and off.
^ Adjust engine idle speed through the IAC motor.
^ Adjust ignition timing.
^ Operate A/C Compressor Clutch relay (if selected).
^ Operate the Up-Shift indicator light.
^ Begin to monitor oxygen sensor. When engine is at operating temperature, the system will leave warm up mode and go into closed loop
operation.
Idle
This is a CLOSED LOOP mode.
With engine idling at operating temperature, the PCM receives inputs from:
^ Air Conditioning Control Position
^ Battery voltage
^ Camshaft position (CMP) sensor
^ Engine coolant temperature (ECT) sensor
^ Manifold Absolute Pressure (MAP) sensor
^ Intake air temperature (IAT) sensor
^ Crankshaft position (CKP) sensor
^ Throttle Position Sensor (TPS)