Page 931 of 1226

303-1 4-7 Electronic Engine Controls 303-1 4-7
DESCRIPTION AND OPERATION
Function The throttle flap position is adjusted and monitored
in a closed control loop. The TP sensor provides
I A CAUTI0N:The throttle control unit (TCU)
the PCM with the information on the actual position
must not be dismantled. No adjustments
of the throttle flap.
or repairs can be made to the TCU.
Item Description
I I I stop screw I
1 2 IToothed segment I
1 3 1 Throttle flap spindle I
1 4 1 Throttle flap return spring I
1 5 1 Intermediate shaft with gear I
1 6 1 Electric motor with pinion I
The APP sensor sends the data containing the
driver's acceleration requirement to the PCM. This
information depends directly on the movement of
the accelerator pedal.
The PCM processes this information and converts
it into an output signal for the throttle control unit
(TCU). This output signal is the control for the
electric motor.
The electric motor moves the throttle flap spindle
by means of the gear set.
Standby function
If a fault develops in the throttle control unit (TCU),
a standby function is carried out. This standby
function allows a slight opening of the throttle flap, so that enough air passes through to allow limited
engine operation.
For this purpose, there is an throttle flap adjustment
screw on the throttle housing. The return spring
closes the throttle flap until the stop of the toothed
segment touches the stop screw. In this way a
defined throttle flap gap is formed for limp home
mode.
The stop screw has a spring loaded pin, which
holds the throttle flap open for limp home mode.
In normal operating mode, this spring loaded pin
is pushed in by the force of the electric motor when
the throttle flap must be closed past the limp home
position
(e.g. for idle speed control or overrun
shutoff).
CPP switch
The CPP switch is located directly on the pedal
box.
The engine management recognises gearshifts
through the CPP switch and thus improves engine
running characteristics.
The CPP switch passes a ground signal to the
PCM when the clutch pedal is depressed
(disengaged).
2006.0 Fiesta 1212006 G204204en
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Page 1189 of 1226
31 0-00-3 Fuel System - General Information 31 0-00-3
GENERAL PROCEDURES
/'
Fuel System Pressure Release(23 420 0)
i
Release
I. WARNINGS:
ADO not smoke or carry lighted tobacco or
open flame of any type when working on or
near any fuel related components. Highly
flammable vapors are always present and
may ignite. Failure to follow these
instructions may result in personal injury.
A~he fuel system remains pressurized for
a long time after the ignition is switched off.
The fuel pressure must be released before
attempting any repairs. Failure to follow this
instruction may result in personal injury.
Remove the fuel pump fuse.
2. Start the engine and allow to idle until the
engine stalls.
3. Crank the engine for approximately five
seconds to make sure the fuel injection
supply manifold pressure has been released.
,1 4. Install the fuel pump fuse.
2006.0 Fiesta 1212006 GI 81 91 en
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Page 1190 of 1226
31 0-00-4 Fuel System - General Information 31 0-00-4
GENERAL PROCEDURES
Fuel Tank Draining(23 551 0)
General Eaui~ment
I Fuel tank draining equipment I
Draining
WARNINGS:
A Do not smoke or carry lighted tobacco or
open flame of any type when working on
or near any fuel related components.
Highly flammable vapors are always
present and may ignite. Failure to follow
these instructions may result in personal
injury.
A The fuel system remains pressurized for a
long time after the ignition is switched off.
The fuel pressure must be relieved before
attempting any repairs. Failure to follow
these instructions may result in personal
injury.
I. Disconnect the battery ground cable. For
additional information, refer to
Section
414-01 [Battery, Mounting and
Cables].
2. Remove the fuel tank filler cap.
3. Using fuel tank draining equipment, drain
the fuel from the fuel tank using a
12.5mm
nylon drain tube.
2006.0 Fiesta 1212006 G210056en
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Page 1219 of 1226

Acceleration Control - 1.3L Duratec-8V
(Rocam)ll.25L Duratec-1 6V (Sigma)ll.4L
31 0-02A-5 Duratec-1 6V (Sigma)/l .6L Duratec-1 6V (Sigma)
31 0-02A-5
DIAGNOSIS AND TESTING
PCM to the electronic throttle body including
the electrical connectors in area "B" (see
system overview).
- There is an obstruction inside the throttle
body bore. Remove the air cleaner outlet pipe
and check for obstructions.
- There is an obstruction inside the electronic
throttle body. Remove the air cleaner outlet
pipe and check that the plate moves freely
against the springs and returns to a slightly
open position. If it does not, install a new
electronic throttle body.
P2176 - Throttle plate adaptation error
- When the ignition is turned off, the throttle
body carries out an adaptation cycle and
spring check. This can be audible after a
short delay (up to 30 seconds) following the ignition key being turned to position
0 and
can be visually observed with the air cleaner
outlet pipe removed. The throttle plate is
moved through a series of positions to check
the TP sensor value and relearn the
electronic throttle body characteristics. If a
concern is detected during this test,
P2176
DTC will be set. If there are already any of
I the other DTCs, the adaptation test could
potentially fail. Therefore the other DTCs
should be resolved first
(e.g. low battery
voltage) and a retest can be carried out by
clearing the DTCs and keying on and off
again. Check the whole area "B" (see system
overview) for any concerns and if no concern
is found, install a new electronic throttle body.
P2100 - H bridge error
- A fault has been detected on the circuit
connecting the electronic throttle body motor
and the PCM. Check for any other
non-electronic accelerator control related
DTCs and rectify them first. Check area "B"
(see system overview) and if no failure is
found, install a new PCM.
PCM Related Codes
The PCM continuously monitors all the sensors. It
also checks that the monitor is functioning as
expected. If there is a fault with the monitor, the
following DTCs will be set.
P2107 - Processor monitoring on the main
controller fault.
P2108 -Analogue to digital converter
- Inferred intake mass air flow lower than
expected
- Engine speed monitor ratio error
- Pedal ratio monitor error
- TP sensor ratio monitor error
- Fault in torque generation
- Fault present in engine speed limitation
Multiple sensor faults can make the PCM assume
that there is a monitor fault. If other DTCs exist,
rectify these first. These DTCs indicate a failure in
area
"A or "B" and they are also related to the
manifold absolute pressure and temperature
(MAPT) sensor and the crankshaft position (CKP)
sensor. If no other failures are found, install a new
PCM.
Indirect Codes
There are two brake pedal switches located under
the brake pedal. Check that both of these are
connected and functioning correctly. A brake pedal
switch concern will only cause the "EAC FAIL"
message to be displayed, it will not lead to a limited
performance mode. Follow WDS instructions.
PO571 - Brake switch error
If the voltage to the accelerator pedal and the
electronic throttle body cannot be regulated
correctly, the components may not operate as
expected. Therefore it is important to detect if there
is a concern in the supply voltage
PO641 - Sensor voltage supply circuit I noisy
signal
PO642 - Sensor voltage supply circuit 1 short
to ground or open circuit
PO643 - Sensor voltage supply circuit 1 short
to battery
PO651 - Sensor voltage supply circuit 2 noisy
signal
PO652 - Sensor voltage supply circuit 2 short
to ground or open circuit
2006.0 Fiesta 1212006 G356253en
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