Ford Falcon. Manual — part 200

303-14-14

Powertrain Control Management

303-14-14

DESCRIPTION AND OPERATION (Continued)

from the ASR on the CAN line, it reduces engine

Catalytic Converter

torque by retarding ignition timing, inhibiting injector

A catalyst is a material that initiates and increases a

operation, closing the throttle plate and leaning the

chemical reaction without itself being consumed. The

air-fuel ratio.

catalytic converter minimises the concentration of

The system continues to monitor for wheel slip. When

toxic gases released to the atmosphere from the

traction is restored, engine torque can be returned to

exhaust system. It contains a catalyst in the form of a

normal levels.

specially treated honeycomb structure saturated with

catalytically active precious metals. As the exhaust

Automatic Transmission Control

gases come in contact with the catalyst, they are

The Powertrain Control Module (PCM) controls the

changed into mostly harmless products. The catalyst

automatic transmission gear shift. The PCM

initiates and speeds up heat producing chemical

calculates the shift points and controls the

reactions of the exhaust gas components so they are

transmission according to driving conditions, engine

used up as much as possible. The catalytic reaction

load and throttle demand. The PCM controls or

only occurs when the air fuel/ratio is near the

monitors the following automatic transmission

stoichiometry point.

functions:

Air Conditioning System

Transmission Range Sensor (TR) <PRNDL>

The PCM controls the air conditioning compressor

Transmission Fluid Temperature Sensor (TFT)

clutch relay on and off in response to the AC Clutch

<TOT>

request sent on the CAN by the Climate Control HIM

Shift Solenoid 1 (SS1) <GSS1>

Module. The Climate Control HIM Module determines

Shift Solenoid 2 (SS2) <GSS2>

the operational state of the AC compressor needed to

maintain a desired evaporator air temperature based

Shift Solenoid 3 (SS3) <MCS1>

on the comfort temperature selected by the driver and

Shift Solenoid 4 (SS4) <MCS2>

passenger.

Variable Pressure Solenoid 5 (VPS)

When the compressor is commanded to turn on, the

Power Control Solenoid 6 (PCS)

PCM utilizes and Air Conditioner Refrigerant Pressure

Lock Up Solenoid 7 (LUS)

Transducer (ACPT) input (B15), and the Air

conditioning Evaporator Air Temperature (AEAT) data Operation, maintenance and the control strategy for

on the CAN to monitor the Air Conditioner system

the transmission are described in Section 307-01,

performance.

Automatic Transmission.

In the event of overheating or a low refrigerant charge

Electronic Sport Shift

condition, the Powertrain Control Module (PCM) shuts

down the air conditioning compressor to prevent

The electronic sports shift feature allows driver control

damage.

of the automatic transmission.

A malfunction of the air conditioning system is

The TRS-A1 <PRNDL> sensor on the side of the

detected by the failure of an individual sensor or by a

transmission housing senses the sport-shift selection

combination of factors calculated from the combined

of “P”, “R”, “N” and “D” position. The resistance of the

outputs of ACPT and AEAT being out of range over a sensor changes for each position and is measured by

period of time. The failure mode can be accessed

the PCM as a voltage on the TRS-A1 input.

through the diagnostic connector using the WDS

The sport shift manual, tip-up and tip-down position is

tester.

sensed by the TRS-A2 sensor, a printed circuit board

with 3 Hall-effect switches in the T-bar console. The

Traction Control

sport shift lever contains a magnet in its base that

On vehicles fitted with the Traction Control System,

activates the appropriate Hall-effect switch in different

the Traction Control (ASR) module works with the

shift position. The switches are resistively multiplexed

Powertrain Control Module (PCM) to minimise wheel

together and are read as a voltage by the PCM on the

slippage. The ASR monitors the speed of each wheel TRS-A2 input.

using wheel sensors on each wheel. Wheel spin is

Column Shift Auto

detected when one of the rear wheels is spinning or

accelerating faster than the front or opposite side

Vehicles fitted with column shift automatics use the

wheel. When spin occurs, the ASR module works to

same TRS-A1 <PRNDL> sensor on the side of the

stop wheel spin by, if necessary, momentarily

transmission as the electronic sport shift. The column

applying the brake of the spinning wheel and signaling shift mechanism moves the sensor through an arc to

the Powertrain Control Module (PCM) to reduce

allow selection of “P”, “R”, “N” and “D” as well as the

engine torque to a specific level.

“3”, “2” and “1” gear positions.

When the PCM receives a torque reduction message

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Powertrain Control Management

303-14-15

DESCRIPTION AND OPERATION (Continued)

a 14.64:1 air-fuel ratio during closed-loop operation.

Control Software

The range of LONGFT is from -35%to +35%. The

ideal value is near 0% but variations of +20%are

Powertrain Control Module Memory

acceptable. Information gathered at different engine

The Powertrain Control Module (PCM) uses flash

speeds and loads is stored in the adaptive fuel tables

Electrically Erasable and Programmable Read Only

for later use in fuel calculations.

Memory (EEPROM) to store the software code

SHRTFT and LONGFT work together. If the HEGO

required to control the powertrain. EEPROM can be

indicates the engine is running rich the PCM will

electrically erased and reprogrammed without

correct the rich condition by moving SHRTFT in the

removing the PCM from the vehicle.

negative range (less fuel to correct for a rich

combustion). If after a certain amount of time

Operating Strategies

SHRTFT is still compensating for a rich condition, the

Adaptive Idle Air Control Strategy

PCM adapts, moving LONGFT into the negative

range to compensate and allows SHRTFT to return to

The adaptive idle air control strategy is designed to

a value near 0%.

adjust the idle calibration to correct for wear and

As the fuel control and air metering components age

ageing of components. When engine conditions meet

and vary from nominal values, the adaptive fuel

the adaptive strategy-learning requirement, the

strategy learns corrections while in closed-loop fuel

strategy monitors the engine and determines the

control. The corrections are stored in a table that is a

values required for ideal idle calibration. The adaptive

function of engine speed and load. The tables reside

strategy stores these values within a table in memory

in Keep Alive Memory (KAM) and are used to correct

for later reference. This table is used by the PCM for

fuel delivery during open and closed-loop operation.

correction factors when controlling idle speed. The

As changing conditions continue the individual cells

adaptive idle table is stored in Keep Alive Memory

are allowed to update for that speed load point. If,

(KAM) and retains the learned values even after the

during the adaptive process, both SHRTFT and

engine is turned OFF. A Diagnostic Trouble Code

LONGFT reach their high or low limit and can no

(DTC) is output when the adaptive strategy has

longer compensate, a Diagnostic Trouble Code (DTC)

reached its limits.

is reported.

Whenever an idle air control system component is

Whenever an injector or the fuel pressure regulator is

renewed or cleaned, or a repair affecting idle is

renewed, the Keep Alive Memory (KAM) should be

performed, the KAM should be reset to ensure the idle

reset to delete the existing adaptive values. The

strategy does not use the previous adaptive values.

system will generate new values for the replaced

Re-training the PCM is described in the ‘Resetting

component. Refer to the ‘Resetting The Powertrain

The Powertrain Control Module’ section.

Control Module’ section.

Adaptive Fuel Control Strategy

Failure Mode Effects Management

The fuel control system uses the adaptive fuel table to

Failure Mode Effects Management (FMEM) is a

compensate for normal variability of the fuel system

Powertrain Control Module (PCM) strategy that

components caused by wear or ageing. During

maintains vehicle operation if one or more of the

closed-loop operation, if the fuel system is biased lean

major input sensors fail.

or rich, the adaptive fuel table will shift the fuel

delivery calculations to remove the bias. The fuel

When an input sensor is out of limits, an alternative

system monitor has two means of adapting; Short

strategy is initiated by the PCM. A fixed value is

Term Fuel Trim (SHRTFT) and Long Term Fuel Trim

substituted for the faulty one. The PCM then

(LONGFT). In both cases the range is displayed as a

continues to monitor the incorrect sensor input. If the

percentage on the WDS tester.

sensor later operates within limits, the PCM returns to

the normal engine operation.

Short Term Fuel Trim (SHRTFT) is a parameter that

indicates short-term fuel adjustments. The Powertrain This mode allows the PCM to compensate for any of

Control Module (PCM) calculates the SHRTFT from

the four major sensor or sensor circuit failures by

Heated Exhaust Gas Oxygen Sensor (HEGO) inputs

either inferring sensor values from remaining

to maintain a 14.64:1 air-fuel ratio during closed-loop

operational sensors or by using calibrated default

operation. A negative percentage means that the

values.

HEGO is indicating a rich mixture and the PCM is

T-MAP sensor failure

attempting to lean the mixture. Ideally, SHRTFT

TP sensor failure

should remain near 0% but has the ability to adjust

ECT sensor failure

from between -25%to +35%.

IAT sensor failure

Long Term Fuel Trim (LONGFT) indicates long-term

fuel adjustments. LONGFT is also referred to as

adaptive fuel control. LONGFT is calculated by the

PCM using information from the SHRTFT to maintain

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Powertrain Control Management

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DESCRIPTION AND OPERATION (Continued)

The road speed limit varies according to model. The

Speed Limiting Strategy

engine speed is limited to approximately 6,000 RPM

NOTE: In some cases, excessive engine or road

(I6) and 5,300RPM (V8). On automatic transmission

speed may be caused by loss of traction due to wheel vehicles, selecting the T-bar in NEUTRAL, “N”

slippage on loose surfaces such as; sand, gravel, wet position limits the engine speed to approximately

roads, mud, snow or ice.

3,000 RPM. Engine and vehicle speed limiting is

Over-revving of the engine in park, neutral or while

nominally controlled by reducing throttle opening to an

driving may also cause the PCM to initiate its speed

appropriate level. Speed overshoots beyond these

limiting strategy.

limits are controlled by momentarily disabling the fuel

injectors.

To prevent damage to the powertrain components,

the Powertrain Control Module (PCM) reduces the

Operating Modes

throttle and disables the fuel injectors whenever the

The mode used by the Powertrain Control Module

engine or road speed reaches specific limits. Once

(PCM) to control the fuel injection and ignition

the speed is reduced to below the set limit, normal

systems depends on the operating conditions.

operation will resume. Diagnostic Trouble Code (DTC)

Operating modes are shown in the diagram below,

P1270 is reported if the engine or road speed exceed

and are described in the following section.

the limit. No repair is required. However, the DTC

should be cleared and the driver informed of the

engine and road speed limits applicable to the vehicle.

Engine Speed Limiting Strategy to prevent damage to

Normal Mode

the powertrain.

In normal operating mode the PCM controls the

Start-Up Mode

powertrain in all operating conditions. Normal mode

commences when the engine is started, either cold or In Start-Up Mode the PCM starts the engine and

hot, then continues throughout the entire range of

manages the engine until it reaches Run Mode. The

engine operation. Normal mode is made-up of two

Start-Up strategy manages the transition between

parts: Start-Up Mode and Run Mode. Each mode has cranking, start-up, cold running and normal engine

further sub-modes that control the powertrain under

operation. The PCM uses several phases to reach

specific conditions. If engine or vehicle speed

Run mode.

exceeds the specified limit, the PCM will initiate the

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Powertrain Control Management

303-14-17

DESCRIPTION AND OPERATION (Continued)

During rapid throttle opening, the PCM will provide

Crank Mode

acceleration enrichment by applying additional pulses

Crank Mode provides the engine with the correct

to the injectors (increasing injection frequency).

parameters for rapid, “no touch” start-up. Crank mode

occurs when the ignition switch is moved to the

Open Loop

START position and the engine speed is below 200

There are two basic modes of fuel injection control:

RPM. In Crank Mode the ignition timing is set to 10

Open Loop and Closed Loop. The PCM will operate in

…BTDC, and the injector pulse width is determined by

Open Loop depending on the driver’s throttle

the signal from the Cylinder Head Temperature

demand, measured by the Throttle Position Sensor

Sensor (CHT).

(TP) <TPS> or when the Heated Exhaust Gas

Whilst cranking, all the injectors fire simultaneously on Oxygen Sensor (HEGO) sensor has not reached

the rising edge of every internal PIP signal. With each operating temperature.

opening, each injector supplies 1/6th (I6) or 1/8th (V8)

The PCM will operate the engine in Open Loop mode

of the fuel required for one cycle.

during warm engine start-up, engine warm-up, part

Once engine speed reaches approximately 240 RPM, throttle mode and wide open throttle conditions.

the PCM will enter under-speed mode.

In Open Loop Mode, the PCM updates the adaptive

To assist in clearing a flooded condition, the PCM

fuel strategy tables stored in memory. The adaptive

disables the fuel injectors if the throttle is held wide

fuel strategy is described in the ‘Adaptive Fuel

open during Crank mode.

Strategy’ section.

Under-Speed Mode

Start-Up and Idle

Under-speed Mode assists the transition from Crank

During Crank Mode and under-speed mode the

mode to Run mode and prevents stall. Under-speed

engine operates in Open Loop mode. The PCM varies

mode occurs once the engine fires, indicated by an

the air-fuel ratio (fuel mixture) to maintain the engine

engine speed of more than 200 RPM. Once the

speed or assist in warm-up. During cold start and

engine fires, the PCM switches to sequential fuel

warm-up the fuel mixture is enriched to promote easy

injection, using Crankshaft Position Sensor (CKP) and starting and smooth idle.

the Camshaft Position Sensors (Cylinder

As the engine warms to normal operating

Identification) (CMP) <CID> to synchronise the fuel

temperature, the fuel injector pulse width is gradually

injection and ignition timing. The injector pulse width

reduced, bringing the mixture with the normal

is switched to use the values stored in the adaptive

operating range. Once the engine is running at normal

fuel strategy tables and trimmed by input from various operating temperature the PCM will switch to Closed

sensors. Ignition timing is held at 10

…BTDC and the

Loop Mode once the engine has been idling for

Electronic Throttle Control (ETC) controlling the air

approximately 60 seconds. The engine normally

intake to maintain idle speed.

operates in Closed Loop Mode when the throttle is

When operating in sequential injection mode, the

closed.

PCM delivers the correct amount of fuel to the port

Wide Open Throttle

above each intake valve, once every 720

… of engine

revolution. The PCM will maintain Under-speed mode Wide Open Throttle (WOT) mode is used to enrich the

until the engine speed reaches or exceeds 400 RPM,

mixture according to the driver’s throttle demand.

and until the engine reaches normal operating

Wide Open Throttle is indicated when the Throttle

temperature, at which time the PCM will switch to Run Position Sensor (TP) <TPS> signal exceeds

mode.

approximately 4 volts. Under these conditions, the

Powertrain Control Module (PCM) enters Wide Open

Run Mode

Throttle mode, enriching the mixture to obtain

The Powertrain Control Module (PCM) switches from

maximum performance. The EVAP Canister Purge

Under-speed to Run mode when engine speed is

Solenoid (EVAP) <CANP>is turned OFF during WOT

greater than 400 RPM. Once the engine and Heated

mode.

Exhaust Gas Oxygen Sensor HEGO) have reached

Closed Loop

normal operating temperature, the PCM operates in

Run Mode and selects either Open or Closed Loop

There are two basic modes of fuel injection control:

operation according to the throttle position and driving Open Loop and Closed Loop. The PCM will operate in

conditions.

Closed Loop depending on the driver’s throttle

In addition to the control sequences for Under-speed

demand, measured by the Throttle Position Sensor

mode, in Run mode the ignition timing is varied by the (TP) <TPS> and when the engine and the Heated

PCM to suit engine load and demand. The engine will Exhaust Gas Oxygen Sensor (HEGO) sensor has

operate in Open or Closed Loop mode according to

reached operating temperature.

the signal from the Throttle Position Sensor (TP)

Closed Loop Mode controls exhaust emissions of

<TPS>.

hydrocarbon (HC), carbon monoxide (CO) and

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