Outputs
AIR CONDITIONING (A/C) CLUTCH RELAY- PCM OUTPUTPower Distribution Center (PDC):
The A/C relay is located in the Power Distribution Center (PDC). The PDC is located in the engine compartment. Refer to label on PDC cover for relay location.
The powertrain control module (PCM) activates the A/C compressor through the A/C clutch relay. The PCM regulates A/C compressor operation by switching the ground circuit for the A/C clutch relay on and off.
When the PCM receives a request for A/C from A/C evaporator switch, it will adjust idle air control (IAC) motor position. This is done to increase idle speed. The PCM will then activate the A/C clutch through the A/C clutch relay. The PCM adjusts idle air control (IAC) stepper motor position to compensate for increased engine load from the A/C compressor.
By switching the ground path for the relay on and off, the PCM is able to cycle the A/C compressor clutch. This is based on changes in engine operating conditions. If, during A/C operation, the PCM senses low idle speeds or a wide open throttle condition, it will de-energize the relay. This prevents A/C clutch engagement. The relay will remain de-energized until the idle speed increases or the wide open throttle condition exceeds 15 seconds or no longer exists. The PCM will also de-energize the relay if coolant temperature exceeds 125° C (257° F).
AUTO SHUTDOWN (ASD) RELAY- PCM OUTPUT
The ASD relay is located in the Power Distribution Center (PDC).
The ASD supplies battery voltage to the fuel injectors, ignition coil and oxygen (O2S) sensor heating elements. The ground circuit for the coil in the ASD relay is controlled by the powertrain control module (PCM). The PCM operates the relay by switching the ground circuit on and off.
CCD BUS (+/-) CIRCUITS-PCM OUTPUTS
The Powertrain Control Module (PCM) sends certain output signals through the CCD bus circuits. These signals are used to control certain instrument panel located items and to determine certain identification numbers.
Data Link Connector Location:
DATA LINK CONNECTOR-PCM INPUT AND OUTPUT
The 16-way data link connector (diagnostic scan tool connector) links the Diagnostic Readout Box (DRB) scan tool or the Mopar Diagnostic System (MDS) with the powertrain control module (PCM). The data link connector is located under the instrument panel to the left of the steering column. For operation of the DRB scan tool, refer to the appropriate Powertrain Diagnostic Procedures service manual.
DUTY CYCLE EVAP PURGE SOLENOID VALVE-PCM OUTPUT
Refer to Emission Control System for information.
FUEL INJECTORS-3.9/5.2/5.9L ENGINES- PCM OUTPUT
Fuel Injectors - Typical:
The fuel injectors are attached to the fuel rail. 3.9L V-6 engines use six injectors. 5.2/5.9L V-8 engines use eight injectors.
The nozzle ends of the injectors are positioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ 2 etc.). This is used to identify each fuel injector with its respective cylinder number.
The injectors are energized individually in a sequential order by the powertrain control module (PCM). The PCM will adjust injector pulse width by switching the ground path to each individual injector on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it receives.
During start up, battery voltage is supplied to the injectors through the ASD relay. When the engine is operating, voltage is supplied by the charging system. The PCM determines injector pulse width based on various inputs.
FUEL INJECTORS-2.5L ENGINE- PCM OUTPUT
Fuel Injectors:
The fuel injectors are attached to the fuel rail. 2.5L 4-cylinder engines use four injectors.
The nozzle ends of the injectors are positioned into openings in the intake manifold just above the intake valve ports of the cylinder head. The engine wiring harness connector for each fuel injector is equipped with an attached numerical tag (INJ 1, INJ 2 etc.). This is used to identify each fuel injector with its respective cylinder number.
The injectors are energized individually in a sequential order by the powertrain control module (PCM). The PCM will adjust injector pulse width by switching the ground path to each individual injector on and off. Injector pulse width is the period of time that the injector is energized. The PCM will adjust injector pulse width based on various inputs it receives.
During start up, battery voltage is supplied to the injectors through the ASD relay. When the engine is operating, voltage is supplied by the charging system. The PCM determines injector pulse width based on various inputs.
FUEL PUMP RELAY-PCM OUTPUT
The PCM energizes the electric fuel pump through the fuel pump relay. Battery voltage is applied to the fuel pump relay when the ignition key is ON. The relay is energized when a ground signal is provided by the PCM.
The fuel pump will operate for approximately one second unless the engine is operating or the starter motor is engaged.
The fuel pump relay is located in the Power Distribution Center (PDC).
GENERATOR FIELD SOURCE (+)- PCM OUTPUT
This output from the Powertrain Control Module (PCM) regulates charging system voltage to the generator field source (+) circuit. The voltage range is 12.9 to 15.0 volts. Models of previous years had used the ASD relay (directly) to apply the 12 volt + power supply to the generator field source (+) circuit.
GENERATOR FIELD DRIVER (-)-PCM OUTPUT
This output from the Powertrain Control Module (PCM) regulates charging system ground control to the generator field driver (-) circuit.
GENERATOR LAMP-PCM OUTPUT
If the powertrain control module (PCM) senses a low charging condition in the charging system, it will illuminate the generator lamp (if equipped) on the instrument panel. This is done through the CCD Bus circuits. For example, during low idle with all accessories turned on, the lamp may momentarily go on. Once the PCM corrects idle speed to a higher rpm, the lamp will go out.
IDLE AIR CONTROL (IAC) MOTOR- 3.9/5.2/5.9L ENGINES-PCM OUTPUT
The IAC motor is mounted to the back of the throttle body and is controlled by the powertrain control module (PCM).
Throttle Body Air Control Passage:
The throttle body has an air control passage that provides air for the engine at idle (the throttle plate is closed). The IAC motor pintle protrudes into the air control passage and regulates air flow through it. Based on various sensor inputs, the powertrain control module (PCM) adjusts engine idle speed by moving the IAC motor pintle in and out of the air control passage. The IAC motor is positioned when the ignition key is turned to the On position.
A (factory adjusted) set screw is used to mechanically limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the PCM.
IDLE AIR CONTROL (IAC) MOTOR- 2.5L ENGINE-PCM OUTPUT
The IAC motor is mounted to the back of the throttle body and is controlled by the powertrain control module (PCM).
The throttle body has an air control passage that provides air for the engine at idle (the throttle plate is closed). The IAC motor pintle protrudes into the air control passage and regulates air flow through it. Based on various sensor inputs, the powertrain control module (PCM) adjusts engine idle speed by moving the IAC motor pintle in and out of the air control passage. The IAC motor is positioned when the ignition key is turned to the On position.
A (factory adjusted) set screw is used to mechanically limit the position of the throttle body throttle plate. Never attempt to adjust the engine idle speed using this screw. All idle speed functions are controlled by the PCM.
IGNITION COIL-3.9/5.2/5.9L ENGINES- PCM OUTPUT
System voltage is supplied to the ignition coil positive terminal. The powertrain control module (PCM) operates the ignition coil. Base (initial) ignition timing is not adjustable. The PCM adjusts ignition timing to meet changing engine operating conditions.
Ignition Coil:
The ignition coil is located near the front of the right cylinder head.
Refer to Ignition System for additional information.
IGNITION COIL-2.5L ENGINE-PCM OUTPUT
System voltage is supplied to the ignition coil p05itive terminal. The powertrain control module (PCM) operates the ignition coil. Base (initial) ignition timing is not adjustable. The PCM adjusts ignition timing to meet changing engine operating conditions.
Ignition Coil:
The ignition coil is located on the side of the engine near the distributor.
Refer to Ignition System for additional information.
MALFUNCTION INDICATOR LAMP-ECM/PCM OUTPUT
Refer to Emission Control System for information.
OVERDRIVE LAMP-PCM OUTPUT
This circuit controls a signal for the operation of the push-button overdrive lamp switch. When the lamp is illuminated, the overdrive is disengaged.
SPEED CONTROL SOLENOIDS-PCM OUTPUT
Speed control operation is regulated by the powertrain control module (PCM). The PCM controls the vacuum to the throttle actuator through the speed
TACHOMETER-PCM OUTPUT
The powertrain control module (PCM) supplies engine rpm values to the instrument cluster tachometer.
THREE-FOUR SHIFT SOLENOID- PCM OUTPUT
This output is used to control the transmission three-four shift solenoid. It is used on 4-speed electronically controlled automatic transmissions only.
TORQUE CONVERTOR CLUTCH (TCC) SOLENOID-PCM OUTPUT
This circuit controls operation of the transmission mounted torque convertor clutch (TCC) solenoid used for torque convertor engagement.
The powertrain control module (PCM) will determine when to engage and disengage the solenoid by monitoring vehicle miles per hour (mph) versus the output voltage of the throttle position sensor. Also needed are various inputs from:
- Transmission temperature sensor
- Output shaft speed sensor
- Module timer
- Engine rpm
- MAP sensor
- Brake switch
MANUAL TRANSMISSION
If equipped with a manual transmission, this PCM output will control operation of the shift indicator lamp (if equipped with lamp). The lamp is controlled by the powertrain control module (PCM). The lamp illuminates on the instrument panel to indicate when the driver should shift to the next highest gear for best fuel economy. The PCM will turn the lamp OFF after 3 to 5 seconds if the shift of gears is not performed. The lamp will remain off until vehicle stops accelerating and is brought back to range of up-shift lamp operation. This will also happen if vehicle is shifted into fifth gear.
The indicator lamp is normally illuminated when the ignition switch is turned on and it is turned off when the engine is started up. With the engine running, the lamp is turned ON/OFF depending upon engine speed and load.
TRANSMISSION RELAY-PCM OUTPUT
The output to this relay provides battery voltage to the overdrive (OD), torque converter clutch (TCC) and governor pressure solenoids. Once battery voltage is applied to the solenoids, they are individually activated by the PCM through OD, TCC and governor pressure outputs. The relay is located in the Power Distribution Center (PDC). Refer to label on PDC cover for relay location.
RADIATOR COOLING FAN RELAY- 2.5L ENGINE-PCM OUTPUT
Vehicles equipped with the 2.5L 4-cylinder engine have an electrical radiator cooling fan. The fan is energized by the Powertrain Control Module (PCM) through this relay. The relay is located in the Power Distribution Center (PDC). Refer to label on PDC cover for relay location.
GOVERNOR PRESSURE SOLENOID-PCM OUTPUT
This solenoid regulates the transmission fluid line pressure to produce the governor pressure necessary for transmission shift control. It is used on 4-speed electronic transmissions only.