Powertrain Control Module (PCM) Outputs
POWERTRAIN CONTROL MODULE (PCM) OUTPUTS
NOTE: Transmission outputs which are not described are discussed in the Transmission/Powertrain.
Air Conditioning Clutch Relay (A/CCR)
NOTE: The PCM PIDs WAC and WACF are used to monitor the A/CCR output.
The A/CCR (may be referred to as the wide open throttle A/C cutoff [WAC] relay) is wired normally open. There is no direct electrical connection between the A/C switch or EATC module and the A/C clutch. The PCM will receive a signal indicating that A/C is requested (for some applications, this message is sent through the communications network). When A/C is requested, the PCM will check other A/C related inputs that are available (such as ACP SW, ACCS). If these inputs indicate A/C operation is OK, and the engine conditions are OK (such as coolant temperature, engine RPM, throttle position), the PCM will ground the A/CCR output, closing the relay contacts and sending voltage to the A/C clutch.
Canister Vent (CV) Solenoid
For information on the CV solenoid, refer to the description of the Evaporative Emission Systems.
Coil Pack
Six-Tower Coil Pack:
The PCM provides a grounding switch for the coil primary circuit. When the switch is closed, voltage is applied to the coil primary circuit. This creates a magnetic field around the primary coil. The PCM opens the switch, causing the magnetic field to collapse, inducing the high voltage in the secondary coil windings and firing the spark plug. The spark plugs are paired so that as one spark plug fires on the compression stroke, the other spark plug fires on the exhaust stroke. The next time the coil is fired the order is reversed. The next pair of spark plugs fire according to the engine firing order.
Coil On Plug (COP)
Coil On Plug (COP):
The COP ignition operates similar to a standard coil pack ignition except each plug has one coil per plug. COP has 3 different modes of operation: engine crank, engine running, and CMP failure mode effects management (FMEM).
Engine Crank/Engine Running
During engine crank the PCM will fire 2 spark plugs simultaneously. Of the 2 plugs simultaneously fired, one will be under compression and the other will be on the exhaust stroke. Both plugs will fire until the camshaft position is identified by a successful camshaft position (CMP) sensor signal. Once the camshaft position is identified, only the cylinder under compression will be fired.
CMP FMEM
During CMP FMEM the COP ignition works the same as during engine crank. This allows the engine to operate without the PCM knowing if cylinder one is under compression or exhaust.
Electric EGR (EEGR) System
For information on the EEGR system, refer to Exhaust Gas Recirculation Systems Electric EGR System (EEGR).
EGR System Module (ESM)
For information on the ESM system, refer to Exhaust Gas Recirculation Systems EGR System Module (ESM).
EGR Vacuum Regulator (EVR) Solenoid
For information on the EVR solenoid, refer to Exhaust Gas Recirculation Systems Differential Pressure Feedback EGR (DPFE) System.
Electric Secondary Air Injection Pump
For information on the electric secondary air injection pump, refer to the description of the Secondary Air Injection (AIR) Systems.
Evaporative Emission (EVAP) Canister Purge Valve
For information on the EVAP canister purge valve, refer to the description of the Evaporative Emission Systems.
Fan Control
Five Hundred/Freestyle/Montego, Crown Victoria/Grand Marquis, Town Car: FCV Duty Cycle Output From PCM (negative Duty Cycle):
LS, Thunderbird: FCV Duty Cycle Output From PCM:
The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure) to determine engine cooling fan needs.
For variable speed electric fan(s):
The PCM controls the fan speed and operation using a duty cycle output on the fan control - variable (FCV) circuit. The fan controller (located at or integral to the engine cooling fan assembly) receives the FCV command and operates the cooling fan at the speed requested (by varying the power applied to the fan motor).
For relay controlled fans:
The PCM controls the fan operation through the fan control (FC) (single speed fan applications), low fan control (LFC), medium fan control (MFC), and/or high fan control (HFC) outputs. Some applications will have the xFC circuit wired to 2 separate relays.
2.0L Focus (with A/C) And Taurus/Sable: PCM FC Output State For Cooling Fan Speeds Chart:
2.0L Escape: PCM FC Output State For Cooling Fan Speeds Chart:
Freestar, Monterey: PCM FC Output State For Cooling Fan Speeds Chart:
For 3-speed fans, although the PCM output circuits are called low, medium, and high tan control (FC), cooling fan speed is controlled by a combination of these outputs. Refer to the table.
Fuel Cap Indicator Lamp
The fuel cap indicator lamp (FCIL) is a communications network message sent by the PCM. The PCM sends the message to illuminate the lamp when the strategy determines that there is a failure in the vapor management system due to the fuel filler cap not being sealed properly. This would be detected by the inability to pull vacuum in the fuel tank, after a fueling event.
NOTE: The FCIL on the Crown Victoria/Grand Marquis, Explorer Sport Trac, and Ranger is a dedicated output signal that is controlled by the PCM.
Fuel Pump
Applications Using a Fuel Pump Relay for Fuel Pump On/Off Control
The fuel pump (FP) is a PCM output signal used to control the electric fuel pump. With the electronic engine control (EEC) power relay contacts closed, vehicle power (VPWR) is sent to the coil of the fuel pump relay. For electric fuel pump operation, the PCM grounds the FP circuit, which is connected to the coil of the fuel pump relay. This energizes the coil and closes the contacts of the relay, sending B+ through the FP PWR circuit to the electric fuel pump. When the ignition key is turned on, the electric fuel pump runs for about one second and will be turned off by the PCM if engine rotation is not detected.
Fuel Pump Driver Module (FPDM) Applications (and Applications with Fuel Pump Functions Incorporated in ear electronic Module)
NOTE:
- For the Thunderbird and LS, the FPDM functions are incorporated in the rear electronic module (REM). The fuel pump operation is the same as in applications using the stand-alone FPDM. However, the REM will transmit diagnostic information over the communications network instead of using a fuel pump monitor (FPM) circuit.
- The Ford GT uses 2 FPDMs to control fuel for the dual-injection fuel delivery system. The PCM will send one FP duty cycle which is used by both pumps.
The fuel pump (FP) signal is a duty cycle command sent from the PCM to the FPDM (Table 2). The FPDM uses the FP command to operate the fuel pump at the speed requested by the PCM or to turn the pump off.
Fuel Injectors
For information on the fuel injectors, refer to the description of the Fuel Systems.
Fuel Pressure Regulator Control (FPRC) Solenoid
For information on the FPRC solenoid, refer to the description of the Fuel Systems.
Generator Regulator Control (GENRC)
For information on the GENRC, refer to the description of the Powertrain Control Module (PCM) Controlled Charging System.
High Fan Control
For information on high fan control, refer to Fan Control.
Idle Air Control (IAC) Solenoid
For information on the IAC solenoid, refer to the description of the Intake Air Systems.
Intake Manifold Runner Control (IMRC) - Electric Actuated
For information on the IMRC electrically actuated, refer to the description of the Intake Air Systems.
Intake Manifold Runner Control (IMRC) - Vacuum Actuated
For information on the IMRC vacuum actuated, refer to the description of the Intake Air Systems.
Intake Manifold Tuning Valve (IMTV)
For information on the intake manifold tuning valve (IMTV), refer to the description of the Intake Air Systems.
Low Fan Control
For information on low fan control, refer to Fan Control.
Medium Fan Control
For information on medium fan control, refer to Fan Control.
Reverse Lamp Control (RLC)
For information on reverse lamp control, refer to Lighting and Horns.
Secondary Air Injection Bypass Solenoid
For information on the secondary air injection bypass solenoid, refer to the description of the Secondary Air Injection (AIR) Systems.
Transmission Control Indicator Lamp (TCIL)
The TCIL is an output signal from the PCM that controls the lamp on/off function depending on the engagement or disengagement of overdrive. Refer to the PCM Inputs Transmission Control Switch.
Vapor Management Valve (VMV)
For information on the vapor management valve (EVAP canister purge valve), refer to the description of the Evaporative Emission Systems.
Powertrain Control Module - Vehicle Speed Output (PCM-VSO)
The PCM-VSO speed signal subsystem generates vehicle speed information for distribution to the vehicle's electrical/electronic modules and subsystems that require vehicle speed data. This subsystem senses the transmission output shaft speed with a sensor. The data is processed by the PCM and distributed as a hard-wired signal or as a message on the vehicle communication network (SCP or high speed-CAN).
The key features of the PCM-VSO system are to:
- infer vehicle movement from the output shaft speed (OSS) sensor signal.
- convert transmission output shaft rotational information to vehicle speed information.
- compensate for tire size and axle ratio with a programmed calibration variable.
- use a transfer case sensor for four wheel drive applications.
- distribute vehicle speed information as a multiplexed message and/or an analog signal.
The signal from a non-contact shaft sensor (output shaft sensor [OSS] or transfer case shaft sensor [TCSS]) mounted on the transmission (automatic, manual, or 4WD transfer case) is sensed directly by the PCM. The PCM converts the OSS or TCSS information to 8000 pulses per mile, based on a tire and axle ratio conversion factor. This conversion factor is programmed into the PCM at the time the vehicle is assembled and can be reprogrammed in the field for servicing changes in the tire size and axle ratio. The PCM transmits the computed vehicle speed and distance traveled information to all the vehicle speed signal users on the vehicle. VSO information can be transmitted by a hard-wired interface between the vehicle speed signal user and the PCM, or by a speed and odometer data message through the vehicle communication network data link.
The PCM VSO hard-wired signal wave form is a DC square wave with a voltage level of 0 to VBAT. Typical output operating range is 1.3808 Hz per 1 km/h (2.22 Hz per mph).
Wide Open Throttle A/C Cut-Off (WAC)
Refer to the air conditioning clutch relay (A/C CR).