Ford Falcon. Manual — part 204

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Powertrain Control Management

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DESCRIPTION AND OPERATION (Continued)

4-8

Ω @20º C.

Connections

3. Reconnect the HEGO harness and start the

PCM Pin A29. . . . . ...Knock Sensor Positive

engine. With the throttle held open to maintain

PCM Pin A40. . . . . ...Knock Sensor Negative

approximately 2,000 RPM, The HEGO voltage

should be switching between High and Low at

Circuit

least once per second; and the rich/lean periods

should be reasonably even. If this does not occur

and the voltage remains constant, either High or

Low, open and close the throttle rapidly and look

for a change in voltage. If the voltage changes

with throttle movement, it indicates that the sensor

is operating correctly but the PCM, is not able to

control the air-fuel ratio.

4. Check the harness for open circuits and short

circuits.

HEGO Sensor Signal Voltage Specification

Diagnosis
Diagnostic Trouble Codes (DTC) are retrieved through

the diagnostic connector using the WDS tester.

DTC applicable to the KS sensor is shown in the

following table.

DTC

Test Mode

Condition

P0325

Cont.

Sensor or circuit

malfunction

Failure Mode

Knock Sensor

Should the KS fail, or produce the incorrect signal, the

Sensor Description

PCM will log a fault code, then revert to minimum

Vehicles fitted with the I6 engine have a linear Knock

ignition advance. The vehicle will otherwise operate

Sensor (KS) located on the left hand side of the

as normal, possibly with marginally less performance,

cylinder block, adjacent to cylinder No. 5 to detect

and some engine knock may occur under certain

pre-ignition detonation (engine knock) within the

conditions.

cylinders. The system detects engine knock by

Testing

comparing engine noise at crank angles when

cylinder pressure of the combustion fuel is highest

Testing Knock Sensor

with engine noise at quieter portions of the engine

1. Disconnect the knock sensor wire connector.

cycle. If the noise is louder, indicating knock, the

2. Measure the resistance across the knock sensor

Powertrain Control Module (PCM) retards ignition

connector terminals using a suitable multimeter.

timing until knocking ceases.

Replace the sensor if not within specification.

The KS is used as a feed-back signal to control

KS Resistance Specification

ignition timing. The KS is a piezo-electric

4 - 6 m

Ω

accelerometer comprised of a piezo crystal mounted

3. Check the harness for open circuits and short

in a ceramic case. Whenever the KS detects knock

circuits.

the PCM retards the ignition timing until the knock

ceases. The PCM then advances the ignition timing in

Feed Forward Inputs

small increments until knock is again detected. The

cycle of retarding and advancing the ignition is

Transmission Range Sensor (TRS-A1)

continuous in Closed Loop Mode, and maintains the

ignition at the optimum spark advance for the fuel

The automatic Transmission Range Sensor A1

quality.

(TRS-A1) <PRNDL>, is incorporated in the inhibitor

switch mounted on the side of the transmission case.

The PCM uses the KS to automatically adjust the

The TRS-A1 sensor reports the current gear lever

engine tune for low octane unleaded fuel or higher

performance Premium unleaded fuel.

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Powertrain Control Management

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DESCRIPTION AND OPERATION (Continued)

selector position to the Powertrain Control Module

DTC

Test Mode

Condition

(PCM).

P0708

KOEO, Cont.

Circuit high

The TRS-A1 signal is used by the PCM for automatic

input

transmission control operations and by the engine

Failure Mode

management system to predict an impending increase

in engine load.

In the event the TRS-A1 fails, or the signal is outside

The TRS-A1 is a rheostat that, with the reference

the expected range, the PCM will log a fault code,

voltage, produces a voltage proportional to the gear

then assume the gear lever selector is in Drive for the

lever selector position.

purpose of setting the idle speed.

The TRS-A1 is a Feed Forward sensor that produces

Testing

a signal change at the PCM before the actual event

takes place. For example, when moving the gear lever The TRS-A1 sensor is tested continuously during

selector from shifting from Park to reverse, the PCM

vehicle operation (cont.) and whenever a Key On

receives the changed signal prior to the engine load

Engine Off (KOEO) test is performed.

actually increasing. This allows the PCM sufficient

1. Connect a WDS tester to the diagnostic

time to open the Idle Air Control Valve (IAC) <ISC>

connector.

valve and increase the fuel injector pulse width to

2. Check the Parameter Identification (PID) value of

compensate for the additional load.

the TR sensor. If the PID value is within

The Key On Engine Running (KOER) self-test is

specification, then check for other Diagnostic

disabled whenever the gear selector is in any gear.

Trouble Codes (DTC) or component faults.

KOER self-test is only operational in either the Park or

Neutral positions.

PID Specification

Electrical Description

PID

Description

Units

The TRS-A1 is series of stepped resistors that will

TR / PRNDL

Park/Neutral

Position

drop Vehicle Reference Voltage (VREF) in seven

Position

distinct steps from Park down to Manual.

(PRNDL) sensor

Connections

Sensor Test

PCM Pin B41. . . . . . . . .. TRS-A1 Sensor

1. Disconnect the harness from the TRS-A1 sensor

PCM Pin 45. . . . . . . . . . . . . .VREF

connector.

PCM Pin B33. . . . . .Signal Return (SIGRTN)

2. Measure the resistance across the TRS-A1

sensor connector terminals using a suitable

Circuit

multimeter. Replace the TRS-A1 sensor if not

within specification.

3. Check the harness for open circuits and short

circuits.

TRS-A1 Resistance Specification

Shift Lever Position

Resistance Nominal

Park (P)

17,300 -20,300

Ω

Reverse (R)

10,900 -11,850

Ω

Neutral (N)

6,500 -7,600

Ω

Drive (D)

4,300 - 5,000

Ω

3rd Gear (3)

2,900 -3,400

Ω

2nd Gear (2)

1,850 -2,200

Ω

1st Gear (1)

1,050 -1,270

Ω

DTCs applicable to the TRS-A1 sensor are shown in

the following table.

Transmission Range Sensor (TRS-A2)

DTC

Test Mode

Condition

The electronic sport shift manual, tip-up and tip-down

position is sensed by 3 Hall-effect switches mounted

P1705

KOEO

Not in Park or

on a printed circuit board in the T-bar console. The

Neutral during

sport shift lever contains a magnet in its base that

self-test (Auto)

activates the appropriate Hall-effect switch in different

P0707

KOEO, Cont.

Circuit low input

shift position. The switches are resistively multiplexed

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Powertrain Control Management

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DESCRIPTION AND OPERATION (Continued)

together and are read as a voltage by the PCM on the Pin-out

Sport Shift

Voltage

TRS-A2 input.

2 and 3

ESS Lever in

2.6V - 3.3V

“Manual”

Connections

Position

PCM Pin B43. . . . . . . . ... TRS-A2 Sensor

2 and 3

ESS Lever in

1.5V - 2.0V

PCM Pin B45. . . . ... . . . . . . . ...VREF

“Tip +” Position

PCM Pin B33. . . . . ..Signal Return (SIGRTN)

2 and 3

ESS Lever in

0.5V - 1.3V

“Tip -” Position

Circuit

Pin-out numbers are marked on the back of the white

ESS connector

Power Steering Pressure Switch

NOTE: This circuit must not remain by-passed or

bridged, since steering load applied when cornering

may stall the engine and cause loss of steering

control.

The Power Steering Pressure Switch (PSP) <PSPS>

which is a pressure sensitive switch that detects when

pressure within the power steering system reaches a

specified level. To prevent engine stall and maintain

idle quality during parking manoeuvres the PCM

boosts the engine idle speed by approximately 100

RPM.
The PSP switch is a normally closed pressure switch.

Failure Mode

Under no load conditions the switch connects the PSP

In the event the TRS-A2 fails, or the signal is outside

pin B31 to Signal Return (SIGRTN). When the power

the expected range, the PCM will log a fault code, and steering load is high, the PSP opens causing 5 volts

then assume the gear lever selector is in the

to be detected at PCM Pin.

automatic plane.

Connections

Testing

PCM Pin B31. . . . . . . . . . ..PSP Signal

The TRS-A2 sensor is tested continuously during

PCM Pin B33. . . . . ..Signal Return (SIGRTN)

vehicle operation and whenever Key On Engine Off

(KOEO) or Key On Engine Running (KOER) tests are

Circuit

performed.
Testing TRSA-2 Sensor
1. Connect a WDS tested to the diagnostic

connector.

2. Check the Parameter Identification (PID) value of

the sensor. If the PID value is within specification,

then check for other Diagnostic Trouble Code

(DTC) or component faults

PID Specification

PID

Description

GLP_D

ESS Lever in Auto Position

Manual

ESS Lever in “Manual” Position

TP+

ESS Lever in “Tip +” Position

Diagnosis

TP-

ESS Lever in “Tip -” Position

Diagnostic Trouble Codes (DTC) are retrieved through

Pin-out

Sport Shift

Voltage

the diagnostic connector using the WDS tester.

1 and 2

All positions

4.8V - 5.2V

DTCs applicable to the PSP switch are shown in the

2 and 3

ESS Lever in

3.7V - 4.2V

following table.

Auto Position

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Powertrain Control Management

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DESCRIPTION AND OPERATION (Continued)

Speed control operation

DTC

Test Mode

Condition

Vehicle speed limiting.

P1650

KOEO

Failure

Engine fan control

P1651

KOER

did not switch

NOTE: A 19-tooth gear is used on the OSS for all

Testing

axle and tyre size variants. Alternative OSS gears will

result in vehicle speed calculation errors and must not

The PSP switch is tested whenever Key On Engine

be used.

Off (KOEO) or Key On Engine Running (KOER) tests

are performed. When a P1650 and a P1651 DTC is

Vehicle speed data is transmitted on the CAN line for

reported after a KOEO and KOER test, check the

the speedometer, odometer, trip computer and

PSP for correct operation.

air-conditioner functions.

Connections

Switch Test

PCM Pin B7

. . ….Vehicle Speed Signal VSS

1. Disconnect the PSP connector harness.

PCM Pin B45

…. Vehicle Reference Voltage (VREF)

2. Using a multimeter with suitable connectors,

measure the resistance if the PSP Switch.

PCM Pin B33..

. . …. Signal Return (SIGRTN)

3. Start and run the engine.

VSS Installation

4. Actuate the PSP switch by turning the steering

wheel and releasing. Ensure that the switch

resistance conforms to specifications. If the switch

is within specifications, check the wiring for open

and short circuits.

Steering

PSP Resistance PSP voltage

Steering turned

Greater than

4.5 - 5.2V

10k

Ω

Steering

Less than 10

Ω

0.0 - 1.0V

released

Vehicle Speed

The PCM determines the vehicle speed from 3

sources depending on vehicle option. Vehicle speed

source, tyre rotations per mile, axle ratio is

Diagnosis

programmed into the PCM using the WDS tester (see

If the sensor is damaged or faulty, but still operating

‘Module Configuration’ in this section).

within the operating range, no fault code will be

Option

VSS input

Signal Type

logged

ABS

Connected to

Square wave

DTCs applicable to this sensor are shown on the

ABS speed

frequency signal following table.

output pin

(0V to 5 V)

DTC

Test Mode

Condition

Traction Control Not used

CAN signal

P0500

KOEO Cont

Missing/erratic

None

Connected to

Square wave

speed signal

output shaft

frequency signal

from ABS, ASR

speed sensor in (0V to 5V)

or OSS

the transmission

housing

Failure Mode

Output Shaft Speed (OSS) Sensor

Failure of the vehicle speed sensor signal source will

result in normal engine running but no speedometer

The output shaft speed sensor is used in vehicles

readout, no speed control operation. Automatic

without the ABS or traction controlled option. It is a

transmission will default to 3rd gear when DRIVE is

gear driven Hall effect sensor mounted in the

selected.

transmission extension. The output signal frequency is

proportional the output shaft speed. The PCM

Testing

calculates vehicle speed using this signal and the

1. Check that the instrument cluster is working

programmed axle ratio and tyre rotation per mile.

correctly by observing warning lamps, tachometer,

The PCM uses vehicle speed signal to control:

fuel and temperature gauges. Rectify before

Automatic transmission gear shifts

continuing.

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