Acceleration Control - 1.3L Duratec-8V
(Rocam)llI25L Duratec-1 6V (Sigma)llI4L
31 0-02A-4 Duratec-1 6V (Sigma)/l .6L
Duratec-1 6V (Sigma)
31 0-02A-4
DIAGNOSIS AND TESTING
Electronic Throttle Body
The electronic throttle body is similar to a
mechanical throttle body used on a cable
accelerator system. Instead of the cable moving
the throttle plate open and closed, it uses an
internal electrical motor that is driven by the PCM.
The electronic throttle body has two sensors that
measure the throttle plate position. The sensors
output a voltage to the PCM corresponding to the
plate position.
When the electronic throttle body motor is not in
use, the throttle plate sits slightly open in a default
position (not idle position). This position is
maintained by two internal springs. One acts
upwards and one downwards. Screws on the
electronic throttle body will not adjust the idle
speed, the idle speed is controlled by the PCM.
PCM
The PCM reads the voltage from the pedal and
converts this signal into a driver request. The driver
request is realized by opening or closing the throttle
body. To do this, the PCM increases or decreases
power to the electronic throttle body motor. The
PCM then checks the signal from the electronic
throttle body throttle position (TP) sensor, to make
sure that the requested position has been
achieved. The PCM also monitors all the sensors
to make sure that the system is functioning as
expected. All electronic accelerator control system
faults will be detected by the PCM and set a
diagnostic trouble code (DTC) which triggers the
electronic accelerator control fail message
accordingly. For safety reasons, some faults will
also reduce the vehicle performance.
Diagnostic Trouble Codes
Description
When a component electrical error is set it means
that the PCM is not receiving the expected signal.
This means that the concern may lie between the
component and the PCM. All wiring and electrical
connectors should be checked before a new
component is installed. Also note that general
vehicle electrical issues can have an effect on other
systems. Battery voltage and relay concerns should
be rectified first.
Accelerator Pedal Codes
These are the DTCs relating to the pedal circuit.
They do not imply necessarily that the accelerator
pedal is at fault, but it will in any case relate to area
"A (see system overview).
P2120 - Accelerator pedal sensor 1 electrical
error
P2122 - Accelerator pedal sensor I electrical
error short to ground or open circuit
P2123 - Accelerator pedal sensor I electrical
error short to battery
P2125 - Accelerator pedal sensor 2 electrical
error
P2127 - Accelerator pedal sensor 2 electrical
error short to ground or open circuit
P2128 - Accelerator pedal sensor 2 electrical
error short to battery
P2138 - Accelerator pedal sensor 1 & 2 ratio
error
Electronic Throttle Body Circuit Codes
These are the DTCs relating to the electronic
throttle body circuit. They do not imply necessarily
( ,)
that the electronic throttle body is the concern, but
it will in any case relate to area "B" (see system
overview).
PO1 20 - Throttle position (TP) sensor 1
electrical error
PO122 - (TP) sensor 1 electrical error short to
ground
PO123 - (TP) sensor 1 electrical error short to
battery or line break
PO220 - (TP) sensor 2 electrical error
PO222 - (TP) sensor 2 electrical error short to
ground or open circuit
PO223 - (TP) sensor 2 electrical error short to
battery
P2135 - (TP) sensor ratio error
P21
I 9 - Throttle plate convergence error
- This is when the throttle plate has not moved
to the requested position in the required time.
This could be caused by the following:
- The electronic throttle body motor is not
receiving the necessary voltage. Check the
--
electronic throttle body motor wiring. The ( PCM is not receiving the correct throttle plate '
position signal from the electronic throttle
body. Check the TP sensor wiring from the
2006.0 Fiesta 1212006 G356253en
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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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Acceleration Control - I .3L Duratec-8V
(Rocam)llI25L Duratec-I 6V (Sigma)llI4L
31 0-02A-6 Duratec-I 6V (Sigma)/l .6L Duratec-1 6V (Sigma)
31 0-02A-6
DIAGNOSIS AND TESTING
PO653 - Sensor voltage supply circuit 2 short Inspection and Verification
to battery
- Check the power supply to the PCM (battery 1. Verify the customer concern.
voltage, relays, wiring harness and electrical 2. Visually inspect for obvious signs of mechanical
connectors as well as fuses). If no concern
or electrical damage.
- Follow WDS instructions. I - Accelerator pedal I Fuse(s) I
- is found, install a new PCM.
PI 71 2 - Electronic gear shift torque demand is Visual
Inspection Chart
N0TE:lf the vehicle is in a limited performance
mode, a system related DTC and the electronic
accelerator control fail light message will illuminate.
If there is a performance issue without these items
the electronic accelerator control system is running
correctly but another issue may exist elsewhere
on the vehicle.
not
a plausible signal (ASM only) - Linkage
- Accelerator cable
- Throttle body
Relay(s)
Wiring harness
Electrical
connector(s)
Accelerator pedal
Throttle body
Mechanical
Electrical
Symptom Chart < .I
Be
aware that installing new system related
components without these
DTCs will not improve
Symptom Chart
- Vehicles With 1.3L Engine
Symptom Possible Sources
Powertrain control
module (PCM)
Action
the
vehicle behavior for general issues such as:
high fuel consumption 3.
If an obvious cause for an observed or reported
concern is found, correct the cause (if possible)
poor idle quality before proceeding to the next step.
poor or no engine start
4. If the cause is not visually evident, verify the
symptom and refer to Symptom Chart.
f
Accelerator pedal is hard to
depress or has a
roughlraspy
or sticky feel
Damaged accelerator cable.
REFER to: Throttle Body (303-
04A, Removal and Installa-
tion).
INSTALL a new accelerator
cable.
Accelerator cable incorrectly installed.
Worn or damaged throttle body.
I Accelerator pedal does not I Weak or broken throttle body I INSTALL a new throttle body. I
CHECK the accelerator cable
for correct installation.
INSTALL a new throttle body.
return freely REFER to: Throttle Body (303-
04A, Removal and Installa-
tion).
I Worn or damaged throttle body. I INSTALL a new throttle body. I
I I I REFER to: Throttle Body (303- 1 04A, Removal and Installa-
tion).
High engine idle speed Damaged accelerator cable. INSTALL a new accelerator
I cable.
2006.0 Fiesta 1212006 G356253en
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31 0-02B-2 Acceleration Control - 2.OL Duratec-HE (M14) 31 0-02B-2
DESCRIPTION AND OPERATION
Acceleration Control
Description on APP sensor 1 and a percentage of duty-cycle
Throttle body output on
APP sensor
2 corresponding to that
accelerator pedal position.
Powertrain control module (PCM)
The PCM reads the output from both the APP
3 Accelerator pedal T sensors requested and torque. converts To achieve the signals the driver into a requested driver
The accelerator pedal incorporates two sensors,
torque, the PCM controls the position of the throttle(
accelerator pedal position (APP) sensor
1, and
plate, ignition timing and fuel injection timing to .
APP sensor 2. Movement of the accelerator pedal
produce the appropriate demanded engine torque
generates a
percentage of reference voltage (0-5V) output. The PCM monitors the actual throttle plate
2006.0 Fiesta 1212006 G422706en
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31 0-02B-3 Acceleration Control - 2.OL Duratec-HE (M14) 31 0-02B-3
DESCRIPTION AND OPERATION
position from the throttle position (TP) sensors to
make sure that the requested position has been
lachieved .
N0TE:Do not install a new accelerator pedal
unless a relevant accelerator pedal DTC has been
stored in the PCM. For additional information refer
to WDS.
The accelerator pedal is a non-serviceable
component which cannot be adjusted and therefore
must not be disassembled or tampered with.
The throttle body is directly controlled by the PCM
and has two TP sensors, TP
1 and TP 2. The TP
sensors output a voltage to the PCM that
corresponds to the actual throttle plate position.
When the throttle body motor is not being powered
up, the throttle plate sits open at approximately 8
degrees from the closed in-bore position. This
position (also referred to as the default position),
is maintained within the throttle body by two internal
compression return springs acting in opposing
directions, these springs are a non-serviceable
item.
The PCM continuously monitors both APP sensors
and both TP sensors to make sure that the system
,is functioning as expected. All acceleration control
( 'system concerns will be detected by the PCM and
the appropriate diagnostic trouble code (DTC) set.
The malfunction indicator lamp (MIL), located in
the instrument cluster will also be illuminated if a
concern is apparent. As the acceleration control
system is of a safety-critical nature, it is possible
that a system concern will result in a reduced
vehicle performance and a DTC stored in the PCM.
For additional information refer to WDS.
2006.0 Fiesta 1212006 G422706en
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