Ford Mondeo (petrol engines). Manual - part 99

Vehicle speed sensor

29 Testing of this component is beyond the
scope of the DIY mechanic, and should be left
to a Ford dealer.

Power steering pressure switch

30 Unplug the electrical connector from the
sensor.
31 Using an ohmmeter, measure the
resistance between the switch terminals. With
the engine switched off, or idling with the
roadwheels in the straight-ahead position,
little or no resistance should be measured.
With the engine running and the steering on
full-lock, the pressure increase in the system
should open the switch contacts, so that
infinite resistance is now measured.
32 If the results obtained show the switch to
be faulty, renew it.

Exhaust gas pressure differential
sensor

33 Testing of this component is beyond the
scope of the DIY mechanic, and should be left
to a Ford dealer.

Oxygen sensor

34 Testing of this component can be done
only by attaching special diagnostic
equipment to the sensor wiring, and checking
that the voltage varies from low to high values
when the engine is running; do not attempt to
“test” any part of the system with anything
other than the correct test equipment. This is
beyond the scope of the DIY mechanic, and
should be left to a Ford dealer.

Removal and refitting

General

35 Before disconnecting any of these
components, always disconnect the power by
uncoupling the battery terminals, negative
(earth) lead first - see Section 1 of Chapter 5.

ECU (Electronic Control Unit)

Note: The ECU is fragile. Take care not to
drop it or subject it to any other kind of
impact, and do not subject it to extremes of
temperature, or allow it to get wet.
36 Carefully prise the power steering fluid
reservoir upwards out of its clip on the
suspension mounting. Unscrew the ECU
connector’s retaining bolt, and unplug the
connector (see illustrations).
37 Working in the passenger compartment,
unscrew the retaining bolt and withdraw the
mounting bracket (see illustration).
38 Lifting the ECU to release it from the
bulkhead carrier bracket, withdraw the unit
(see illustration).
39 Refitting is the reverse of the removal
procedure. Whenever the ECU (or battery) is
disconnected, the information relating to idle
speed control and other operating values will
be lost from its memory until the unit has re-
programmed itself; until then, there may be
surging, hesitation, erratic idle and a
generally-inferior level of performance. To
allow the ECU to re-learn these values, start
the engine and run it as close to idle speed as
possible until it reaches its normal operating

temperature, then run it for approximately two
minutes at 1200 rpm. Next, drive the vehicle
as far as necessary - approximately 5 miles of
varied driving conditions is usually sufficient -
to complete the re-learning process.

Air mass meter

40 Releasing its wire clip, unplug the meter’s
electrical connector (see illustration).
41 Release the clips and lift the air cleaner
cover, then release the two smaller clips and
detach the meter from the cover (see
illustration).
42 Slacken the clamp securing the meter to
the resonator hose, and withdraw the meter.
43 Refitting is the reverse of the removal
procedure. Ensure that the meter and air
cleaner cover are seated correctly and securely
fastened, so that there are no air leaks.

Crankshaft speed/position sensor

44 Refer to Chapter 5.

Camshaft position sensor

45 Remove the air mass meter and resonator
(refer to Chapter 4) to gain access to the
sensor (see illustration). Release the fuel
feed and return hoses from their clip.
46 Releasing its wire clip, unplug the
sensor’s electrical connector. Remove the
retaining screw, and withdraw the sensor from
the cylinder head; be prepared for slight oil
loss.
47 Refitting is the reverse of the removal
procedure, noting the following points:

6•12 Emissions control systems

4.36A  Unclip and lift power steering fluid

reservoir - take care not to spill fluid . . .

4.36B  . . . unscrew bolt (arrowed) to

release ECU’s electrical connector

4.37  Unscrew retaining bolt and withdraw

ECU’s mounting bracket . . .

4.40  Unplugging the air mass meter’s

electrical connector . . .

4.38  . . . then lift ECU to disengage it, and

withdraw it

4.41  . . . release clips to separate meter

from air cleaner cover

(a) Apply petroleum jelly or clean engine oil

to the sensor’s sealing O-ring.

(b) Locate the sensor fully in the cylinder

head, and wipe off any surplus lubricant
before securing it.

(c) Tighten the screw to the specified torque

wrench setting.

Coolant temperature sensor

48 Refer to Chapter 3, Section 6.

Intake air temperature sensor

49 Remove the air mass meter and resonator
(refer to Chapter 4) to gain access to the
sensor (see illustration).
50 Releasing its clip, unplug the sensor’s
electrical connector, then unscrew the sensor
from the resonator.
51 Refitting is the reverse of the removal
procedure. Tighten the sensor to the specified
torque wrench setting; if it is overtightened, its
tapered thread may crack the resonator.

Throttle potentiometer

52 Remove the plenum chamber (see
Chapter 4). Releasing its wire clip, unplug the
large electrical connector (next to the fuel
pressure regulator).
53 Releasing its wire clip, unplug the
potentiometer’s electrical connector. Remove
the retaining screws, and withdraw the unit
from the throttle housing (see illustration). Do
not force the sensor’s centre to rotate past its

normal operating sweep; the unit will be
seriously damaged.
54 Refitting is the reverse of the removal
procedure, noting the following points:
(a) Ensure that the potentiometer is correctly

orientated, by locating its centre on the D-
shaped throttle shaft (throttle closed), and
aligning the potentiometer body so that
the bolts pass easily into the throttle
housing.

(b) Tighten the screws evenly and securely

(but do not overtighten them, or the
potentiometer body will be cracked).

Vehicle speed sensor

55 The sensor is mounted at the base of the
speedometer drive cable, and is removed with
the speedometer drive pinion (see
illustration). Refer to the relevant Section of
Chapter 7, Part A or B, as applicable.

Power steering pressure switch

56 Releasing its clip, unplug the switch’s
electrical connector, then unscrew the switch
(see illustration). Place a wad of rag
underneath, to catch any spilt fluid. If a
sealing washer is fitted, renew it if it is worn or
damaged.
57 Refitting is the reverse of the removal
procedure; tighten the switch securely, then
top-up the fluid reservoir (see Chapter 1) to
replace any fluid lost from the system, and
bleed out any trapped air (see Chapter 10,
Section 33).

Exhaust gas pressure differential
sensor

Note: See also Section 6, illustration 6.21.
58 If better access is required, remove the
resonator (see Chapter 4).
59 Releasing its wire clip, unplug the
sensor’s electrical connector. Remove the
two retaining screws, withdraw the unit from
the bulkhead mounting bracket, then
disconnect the two vacuum hoses. Note that
the hoses are of different sizes, to ensure that
they cannot be mixed up on reconnection.
60 Check the condition of both hoses, and
renew them if necessary (see Chapter 1).
61 Refitting is the reverse of the removal
procedure. Ensure that the hoses are securely
connected to the correct unions.

Oxygen sensor

Note: The sensor is delicate, and will not work
if it is dropped or knocked, if its power supply
is disrupted, or if any cleaning materials are
used on it.
62 Release the sensor’s electrical connector
from its bracket on the engine/transmission
front mounting, and unplug it to disconnect
the sensor (see illustration).
63 Raising and supporting the front of the
vehicle if required to remove the sensor from
underneath, unscrew the sensor from the
exhaust system front downpipe; collect the
sealing washer (where fitted).
64 On refitting, clean the sealing washer

Emissions control systems  6•13

6

4.56  Power steering pressure switch is

screwed into pipe at right-hand rear end of

engine

4.62  Oxygen sensor is screwed into

exhaust system front downpipe . . .

4.49  Intake air temperature sensor

(arrowed) is screwed into underside of air

intake resonator

4.53  Throttle potentiometer is secured by

two screws (arrowed)

4.55  Vehicle speed sensor “A”, with its

electrical connector “B”

4.45  Camshaft position sensor is located

at left-hand rear end of cylinder head

(where fitted) and renew it if it is damaged or
worn. Apply a smear of anti-seize compound
to the sensor’s threads, to prevent them from
welding themselves to the downpipe in
service. Refit the sensor, tightening it to its
specified torque wrench setting; a slotted
socket will be required to do this (see
illustration). Reconnect the wiring and refit
the connector plug.

General description

1 This system is fitted to minimise the escape
of unburned hydrocarbons into the
atmosphere. The fuel tank filler cap is sealed,
and a charcoal canister is mounted
underneath the tank, to collect and store
petrol vapours generated in the tank when the
vehicle is parked. When the engine is running,
the vapours are cleared from the canister
(under the control of the ECU via the canister-
purge solenoid valve) into the inlet tract, to be
burned by the engine during normal
combustion - see illustration 2.1A.
2 To ensure that the engine runs correctly
when it is cold and/or idling, and to protect
the catalytic converter from the effects of an
over-rich mixture, the canister-purge solenoid
valve is not opened by the ECU until the
engine is fully warmed-up and running under
part-load; the solenoid valve is then switched
on and off, to allow the stored vapour to pass
into the inlet.

Checking

3 Poor idle, stalling and poor driveability can
be caused by an inoperative canister-purge
solenoid valve, a damaged canister, split or
cracked hoses, or hoses connected to the
wrong fittings. Check the fuel filler cap for a
damaged or deformed gasket.
4 Fuel loss or fuel odour can be caused by
liquid fuel leaking from fuel lines, a cracked or
damaged canister, an inoperative canister-

purge solenoid valve, and disconnected,
misrouted, kinked or damaged vapour or
control hoses.
5 Inspect each hose attached to the canister
for kinks, leaks and cracks along its entire
length. Repair or renew as necessary.
6 Inspect the canister. If it is cracked or
damaged, renew it. Look for fuel leaking from
the bottom of the canister. If fuel is leaking,
renew the canister, and check the hoses and
hose routing.
7 If the canister-purge solenoid valve is
thought to be faulty, unplug its electrical
connector and disconnect its vacuum hoses.
Connect a battery directly across the valve
terminals. Check that air can flow through the
valve passages when the solenoid is thus
energised, and that nothing can pass when the
solenoid is not energised. Alternatively,
connect an ohmmeter to measure the
resistance across the solenoid terminals, and
compare this reading to the one listed in the
Specifications Section at the beginning of this
Chapter. Renew the solenoid valve if it is faulty.
8 Further testing should be left to a dealer
service department.

Component renewal

Charcoal canister-purge solenoid
valve

9 If better access is required, remove the
plenum chamber (see Chapter 4). Disconnect
the battery negative (earth) lead - see Sec-
tion 1 of Chapter 5.

10 Unplug the valve’s electrical connector
(see illustration). Unclip the valve from the
bulkhead, then disconnect its vacuum hoses
and withdraw it.
11 Refitting is the reverse of the removal
procedure.

Charcoal canister - Saloon and
Hatchback models

Note: Read through this procedure carefully
before starting work, and ensure that the
equipment is available that is required to carry
it out safely and with minimum risk of damage,
and to align the crossmember with sufficient
accuracy on reassembly.
12 Remove the fuel tank (see Chapter 4).
13 Ensure that the rear of the vehicle’s body
is supported securely on axle stands, then
support the rear suspension crossmember
with a jack. Remove the roadwheels and
unscrew the rear suspension strut top
mounting bolts (two per side - see Chapter
10).
14 Use white paint or similar (do not use a
sharp-pointed scriber, which might break the
underbody protective coating and cause
rusting) to mark the exact relationship of the
crossmember to the underbody. Unscrew the
four mounting bolts (see illustration). Lower
the crossmember approximately 3 inches (75
mm) on the jack, and support it securely. 

Warning: DO NOT place any part
of your body under the vehicle
when it is supported only by a
jack!

5 EVAPorative emissions control

(EVAP) system - 
general information, checking
and component renewal

6•14 Emissions control systems

4.64  . . . slotted socket will be required to

tighten sensor with a torque wrench

5.10  Charcoal canister-purge solenoid

valve (arrowed) is clipped to bulkhead

behind engine

5.14  Support rear suspension

crossmember on jack, and remove

mounting bolts (arrowed) . . .

5.15  . . . lower crossmember by 3 inches,

and unscrew charcoal canister assembly

rear retaining bolts (arrowed) . . .

5.16  . . . unplug hoses (arrowed) from

canister assembly . . .

15 Unscrew the two rearmost canister
assembly retaining bolts (see illustration).
16 Unplug the two hoses from the canister
assembly, noting which way round they are
fitted (see illustration).
17 Unscrew the canister assembly’s front
retaining bolt (see illustration). Withdraw the
canister assembly.
18 Release the clip, and drive out the pin to
separate the canister from its bracket (see
illustration).
19 On reassembly, refit the canister to its
bracket and refit the assembly to the vehicle,
tightening the retaining bolts securely, and
ensuring that the two hoses are securely
reconnected to their original unions.
20 Offer up the crossmember and refit the
crossmember bolts, tightening them only
lightly at this stage.
21 The crossmember must now be aligned
on the underbody. Ford specify the use of
service tool 15-097, which is a pair of tapered
guides, with attachments to hold them in the
crossmember as it is refitted (see
illustration). However, since the working
diameter of these tools is 20.4 mm, and since
the corresponding aligning holes in the
crossmember and underbody are 21 mm and
22 mm in diameter, there is a significant in-
built tolerance possible in the crossmember’s
alignment, even if the correct tools are used. If
these tools are not available, align the
crossmember by eye, centring the

crossmember aligning holes on those of the
underbody, and using the marks made on
removal for assistance. Alternatively, use a
tapered drift such as a clutch-aligning tool, or
a deep socket spanner of suitable size.
22 Once the crossmember is aligned as
precisely as possible, tighten its bolts to the
specified torque (see Chapter 10
Specifications) without disturbing its position
(see illustration). Recheck the alignment
once all the bolts are securely tightened.
23 The remainder of the refitting procedure is
the reverse of removal.
24 Remember that, since the rear suspension
crossmember has been disturbed, the wheel
alignment and steering angles must be
checked fully and carefully as soon as
possible, with any necessary adjustments
being made. This operation is best carried out
by an experienced mechanic using proper
checking equipment; the vehicle should
therefore be taken to a Ford dealer or similar
for attention.
Charcoal canister - Estate models
25 Disconnect the battery negative (earth)
lead - see Section 1 of Chapter 5.
26 Raise the rear of the vehicle, and support
it securely on axle stands. 

Warning: DO NOT place any part
of your body under the vehicle
when it is supported only by a
jack!

27 Disconnect the two hoses from the
canister assembly, noting which way round
they are fitted.
28 Unscrew the canister assembly retaining
bolt and withdraw the assembly, unclipping it
from the front mounting.
29 Remove the plastic cover, and drive out
the pin to separate the canister from its
bracket (see illustration).
30 On refitting, secure the canister to its
bracket, and refit the assembly to the vehicle.
Tighten the retaining bolt securely, and ensure
that the two hoses are securely reconnected
to their original unions.

General information

1 To reduce oxides of nitrogen (NO

x

)

emissions, some of the exhaust gases are
recirculated through the EGR valve to the inlet
manifold. This has the effect of lowering
combustion temperatures.
2 The system consists of the EGR valve, the
EGR exhaust gas pressure differential sensor,
the EGR solenoid valve, the ECU, and various
sensors - see illustration 2.1A. The ECU is
programmed to produce the ideal EGR valve
lift for each operating condition.

Checking

EGR valve

3 Start the engine and allow it to idle.
4 Detach the vacuum hose from the EGR
valve, and attach a hand vacuum pump in its
place.
5 Apply vacuum to the EGR valve. Vacuum
should remain steady, and the engine should
run poorly.
(a) If the vacuum doesn’t remain steady and

the engine doesn’t run poorly, renew the
EGR valve and recheck it.

(b) If the vacuum remains steady but the

engine doesn’t run poorly, remove the

6 Exhaust Gas Recirculation

(EGR) system - 
general information, checking
and component renewal

Emissions control systems  6•15

6

5.22  . . . ensure aligned crossmember

does not move - Ford tools used here -

while mounting bolts are tightened

5.29  Charcoal canister assembly - Estate
models - showing plastic cover (arrowed)

and pin securing canister to mounting

bracket

5.17  . . . and remove front retaining bolt

(arrowed) to release canister assembly -

Saloon and Hatchback models

5.18  Release clip and drive out pin to

separate canister from mounting bracket

5.21  Refitting rear suspension crossmember

with Ford service tools (arrowed) in place to

align it with underbody . . .