Chrysler Concorde/Intrepid/LHS/New Yorker/Vision 1993-1997

General Information

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See Figure 1



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Fig. Fig. 1: Some of the input and outputs of the PCM

The engine computer, which controls the fuel injection system on the vehicles covered by this guide, is referred to as the Powertrain Control Module (PCM). The PCM is a digital computer containing a microprocessor. The PCM receives input signals from various switches and sensors that are referred to as engine computer inputs. Based on these inputs, the PCM adjusts various engine and vehicle operations through devices referred to as outputs.

The PCM inputs are as follows:



Air conditioning controls
 
Battery voltage
 
Brake switch
 
Camshaft position sensor
 
Crankshaft position sensor
 
Intake Air Temperature (IAT) sensor (3.3L)
 
Distance sensor
 
Transaxle Control Module (TCM)
 
Transaxle gear engagement (From the TCM)
 
Torque management input (From the TCM)
 
Engine Coolant Temperature (ECT) sensor
 
Knock Sensor (3.5L)
 
Manifold Absolute Pressure (MAP) sensor
 
Heated oxygen sensors
 
Ignition sense
 
Throttle Position Sensor (TPS)
 
Park/Neutral switch
 
SCI receive
 
Speed control
 
Vehicle Speed Sensor (VSS)
 

The PCM outputs are as follows:



Air conditioning clutch relay
 
Alternator field
 
Idle Air Control (IAC) Motor
 
Auto Shutdown (ASD) and fuel pump relays
 
EGR solenoid
 
Duty cycle EVAP purge solenoid
 
Data link connector (CCD and SCI Transmit)
 
Electric EGR Transducer (EET)
 
Fuel injectors
 
Alternator field
 
High speed fan relay
 
Ignition coils
 
MTV solenoid
 
Speed control relay
 
Speed control vent relay
 
Speed control vacuum relay
 

Based on inputs it receives, the PCM adjusts fuel injector pulse width, idle speed, ignition timing and canister purge operation. The PCM regulates the cooling fans, air conditioning and speed control systems. The PCM changes the alternator charge rate by adjusting the generator field.

The ASD relay and fuel pump relay are mounted externally, but turned on and off by the PCM. The camshaft and crankshaft signals are sent to the PCM. If the PCM does not receive both signals within approximately one second of engine cranking, it deactivates the ASD and fuel pump relays. When these relays are deactivated, the power is shut off to the fuel injectors, ignition coils, fuel pump and heating element in each oxygen sensor.

The PCM contains a voltage converter that changes battery voltage to a regulated 8.0 volts. The 8.0 volts power the camshaft position sensor, crankshaft position sensor and vehicle speed sensor. The PCM also provides a 5.0 volt supply for the coolant temperature sensor, intake air temperature sensor and throttle position sensor.

 
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