1988 CITROEN CX air condition

USE OF THE MANUAL
PRESENTATION
The Repair Manual comes in a binder with a “Mu/to” type
mechanism to facilitate the filing of additive sheets
or the removal of a part for operation in the workshop.
The MECHANICAL COMPONENTS, PART 1 VOLUME (8531) covers operations on the MECHANlCAL
COMPONENTS and the BODYWORK which may be carried out by a general workshop.
It is divided into 15 chapters separated by vinyl tab inserts numbered @ to @
General
Engine
Fuel system-Carburettor
Ignition system
Clutch
Gearbox-Drive shafts
Source and reserve of pressure
Front axle Rear axle
Suspension - wheels - tyres
Steering
Braking system
Electrical equipment and radio
Heater, ventilation and air-conditioning
Bodywork
COMPOSITION OF A CHAPTER
Each chapter includes:
-
the list of operations in it,
-
the operations in numerical order.
OPERATIONS
The operation references are made up as follow: MA 100 - 00 II a
-
a) z T-r TiiTz
a) vehicle code letters: MA
b) three figure number identifying the assembly or the assembly part
c) figure indicating the type of operation:
-
the figures 000 indicate the vehicle specification
- the figures 00 indicate the assembly specification
- the figures 0 indicate checks and adjustments
- the figures 1 indicate removals and refittings
- the figures 2 indicate dismantling and re-assembly
-
the figures 3 indicate reconditioning
d) figure /I,... /2.../... standing for a variant,
e) letter: a, b, standing for an evolution
rious operations are presented:
1’ either through photos, drawings and texts,
hrough photos, drawings and symbols.
‘!%.OSSARY has been placed at the beginning of each volume for this purpose.
e glossary (the one in the Mechanical Components volume is different from the one in
caning for each symbol has been translated into nine languages.
kts in a removable set of “plastic” sheets bound with one manceuvrable me
ion of one or several pages (and obtain photocopies from them, for instance). the Bodywork volur nel,
‘tal r ing to facilitate the
85 31

REMOVING AND REFITTING
THE ENGINE/GEARBOX ASSEMBLY
- 2.5 LITRE CX WITH PETROL INJECTION -
REMOVAL
Support the car on stands horizontally, Fig. I using
the three stands 6602-T, in order to facilitate the
removal of the power unit assembly and to reposition
it more easily on the stands.
Depressurize the hydraulic system.
Drain the brake accumulator.
Set the height control to the “low” position
Remove:
- the battery,
- the bonnet,
- the front wheel,
- the spare wheel
- the protection plate located under the spare wheel,
Drain the cooling circuit via the drain hose of the
radiator.
Take off the crankcase drain plug (I 1, Fig. II.
Remove the drive-shafts:
(Refer to Op @ MA.372. l/l)
Uncouple: hoses (6) and (71, Fig. IV (protecting the
alternator from water entry at “a”).
Disconnect the engine cooling fan thermal switch.
Remove the engine heat sink.
Extract, Fig. Ill:
- the screws that secure horn (2) support, passing
through the wheelarch,
- the wheelarch lining. Disconnect:
- wiring harnesses (3) from the battery positive lead,
Fig. Ill,
- the ground cable from the gearbox,
- the wiring harness from the reversing lamp switch.
Remove, Fig. Ill:
- the pressure regulator accumulator,
- pipe (4) between pressure regulator and brake accu-
mulator.
Vehicle with air conditioning option:
- the belt protective cover,
- the air conditioning compressor drive belt
Uncouple:
- the air intake casing position accelerator cable,
- the high pressure pump rubber suction pipe,
- the high pressure pump outlet pipe (5) and its attach-
ment, Fig. Ill.
Disconnect: Fig. V
- the throttle spindle switch (IO),
- knock sensor (14).
Uncouple: Fig. V
- pressure sensor pipe(91,
- supplementary air pipe (I I),
- cylinderhead cover pipe (I 21,
- breather pipe (8).
Remove suction pipe (I 3) situated between the flow-
meter and the turbocharger or between the flowme-
ter and the inlet manifold.

le up the exhaust system. econnect, Fig. IV and V:
- connectors 11 I),
turaily aspirated engines w/th EN, fitted with
seals:
Tighten the flange to 1.6 mda
On the turbocharged engines with EH, fitted with
NEW nuts and seals:
Refit: Fig. I and II, - sensor (12) (with biue /dent mark),
- sensor (13) (with no ident mark),
- HT coil 191 cyls 1 and 4 (with yellow /dent mark),
HT coil i IO) cyls 2 and 3 (w/t/r fro markl,
- the suppressors,
- the reversing larnp switch wrring harness,
- the throttle spindle switch (141,
- knock sensor (I 8).
- flexible pipe (2) to the pressure release valve outlet,
- exhaust pipe (4) to the turbo, screws (31, distance
pieces (51,
- screw (6) and adjusting shims.
There should be a 5 mm clearance at least between
the exhaust pipe and the engine crankcase. Recouple, Fig. V and VI:
- the water hoses,
- air circurt pipes (151, (161, (17). (20) and (211,
- petrol circuit pipes (I 9),
- gear shift link rods,
- the accelerator cable.
Tighten, Fig. I and II:
- turbocharger nuts fin the correct sequence), Fig. II,
- flexible hose (2) screws (3) and nuts (I 1 to
2.5 mdaN,
- screw (6) to 5 mdaN. Fit:
- the driveshafts,
(See Op. @ MA 372-l/11
- the radiator,
- the bonnet,
- the battery,
Refit: Fig. Ill
- the pressure regulator and compressor holder (air
conditioning option) together with its shims; tigh-
ten nuts (7) to 5 mdaN. - the protection plate located under the spare
wheel.
Check the oil levels. Top up if necessary.
Vehicles with air-conditioning: Fill up the cooling circuit (wrth the heater open) and
carry out the bleeding operation.
- the compressor belt and protection cover,
- the pressure regulator accumulator, fitted with a
NEW seal,
- the HP pump outlet pope, fitted with a NEW sea/
and its fastenings (8),
- the pipe situated between the pressure regulator
and the brake accumulator, fitted with NEWseals,
- the HP pump rubber suction pipe,
- the horn. (As per Op @ MA 230.0/l/.
Bleed the front brakes.
(Refer to Op. MA 453.0/l/.
Check the gear change.
Lower the vehicle to the ground.

GENERAL FEATURES OF THE CARBURATION
FITTING. Fig. I:
5. FIN the tamper-proof protective plug (a):
- load gun A,
- screw tool E onto gun A,
- position plug (a) in its housing on the carburettor (make sure it is fitted the right way round Fig. 111,
- actuate the gun until the plug is properly located.
EXHAUST EMISSION CONTROL
In order to comply with current regulations, the checking and adjustment of the exhaust emission from vehicles
with a petrol engine must, without fail, be performed after the following operations:
I. ENGINE REPLACEMENT.
II. CARBURETTOR REPLACEMENT.
Ill. WORK ON THE CARBURETTOR.
Replacement of parts of the carburettor.
Carburettor adjustment.
Work on the carburettor controls.
IV. WORK ON THE INLET MANIFOLD.
Replacement or removal of:
- the inlet manifold,
- the air filter,
- crankcase gas recirculation system
V. WORK ON THE ENGINE.
Rocker adjustment.
Replacement or removal of:
- the cylinder head,
- the camshaft,
- the rockers,
- the valves,
- the liners and pistons.
VI. WORK ON THE IGNITION.
Replacement or reconditioning of the distributor (wholly or partially)
Adjustment or replacement of the sparking plugs.
Adjustment of the ignition timing.
VII. WORK ON EXHAUST SYSTEM.
Replacement or removal of:
- the exhaust manifold,
- the silencer or any part of the exhaust.
VIII. WORK ON THE EMISSION CONTROL SYSTEM.
When the vehicle is fitted with a specific equipment (e.g. on vehicles of SWEDEN, AUSTRALlA or JAPAN type)

CHECKING AND ADJUSTING
THE INJECTION SYSTEM
III. - ADJUSTING THE ROTO-DIESEL INJECTION PUMP CONTROLS
DPC type pump from engine M 25/648, Fig. I
DPA type pump from engine M 25/660, Fig. II
Checking the fast-idle control
Ensure that lever (7) is against its stop, by pushing
it in the direction of arrow (-).
If not, adjust tension of cab/e by means of cable end
clamp (6). Complete tightening of cable using sheath
tensioner (41.
Checking the fast-idle control
Make sure that the cable is slack.
If not, check the operation of the thermal sensor (101
located on the water outlet duct: the cable must ope-
rate over a range of 6 mm between its “ENGINE
COLD” and “ENGINE WARM” positions.
Adjusting the accelerator control
Engine stopped:
Fully depress the accelerator pedal.
Check that lever (I) is against stop (2).
If not, move pin (3) of accelerator cable.
Make sure that, at idle, lever (I) is against stop (5).
Adjusting the anti-stalling device
Engine running:
Insert a 1.5 mm thick shim (DPC pump, Fig. I)
2 mm thick shim (DPA pump, Fig. II)
between lever (I) and stop-screw (5) at “b”.
Place a 3 mm dia. rod through the hole in lever (7)
at “a” by pushing STOP lever (9) outwards. Set the engine speed to:
800 t 50 rpm (DPC pump)
800 f 25 rpm (DPA pump)
by turning stop screw (5).
Remove the 3 mm dia. rod and the shim
Adjust the idling speed to:
800 + 25 rpm
by turning stop screw (8).
Checking the engine deceleration:
Accelerate the engine to 3.000 rpm, then release the
accelerator lever sharply.
- if the deceleration is too fast (engine often stalling),
unscrew stop-screw (5) by 114 turn,
- if the deceleration is too slow (poor engine braking),
screw up stop-screw (51 by l/4 turn.
In both cases, check the idling speed and adjust if
necessary.
If the malfunction continues to exist, carry out the
adjustments again.
Check the efficiency of the mechanically operated
STOP control (9).
Note: The setting figures are identical if the vehicle
is equipped with air-conditioning and the adjustments
are to be effected with the air-conditioning off.

REPAIR OF THE HYDRAULIC SYSTEM
FITTING PRECAUTIONS
PRECAUTIONS TO BE TAKEN WHEN WORKING ON
THE HYDRAULIC UNITS OR THE SYSTEM
The correct functioning of the entire system presupposes perfect cleanliness of the fluid and the hydraulic
units. Stringent precaut!ons must therefore be taken when working on the hydraulic system and during the
storage of the fluid and components. 1. HYDRAULIC FLUID:
Mineral hydraulic fluid (LHM) is the only suitable type and must be used to the exclusion of all others in the hydrau-
lic system of the car.
This LHM fluid is green in co/our and similar to engine oil.
The use of any other would ruin the rubber rings and seals in the system. 2. RUBBER UNITS AND PARTS:
Suitable components are identified by their green co/our and may only be replaced by genuine replacement
components painted or marked in green.
All rubber components (seals, hoses, diaphragm, etc...) are of a special quality for use with LHM fluid and are
identified by their white or green colour. 3. STORAGE:
Components must be stored, full of fluid and blanked off. Like the piping, they must be protected against shock
and the ingress of dust.
Rubber tubing and joints must be stored away from dust, air, light and heat.
LHM hydraulic fluid must be stored in its original containers carefully sealed. We advise the use of one litre (for
topping up) or five litre cans (for refilling) to avoid having to keep opened containers. 4. CHECKS BEFORE CARRYING OUT WORK:
Before-working on the hydraulic system in case of faulty operation, ensure the following:
a) That the controls or the mechanical linkages of the units or the group of hydraulic units involved are
not stiff in operation
I I
b) and that the HP circuit is under pressure, as follows:
With the engine at idling speed:
- Unscrew the pressure-release screw on the pressure regulator by one turn to one turn and a half: a sound
of leakage should be heard from the regulator.
- Retighten the release screw: cut-out must occur which results in a reduction in the running noise emitted
by the H.P. pump.
If not, check in the following sequence:
- that there is sufficient fluid in the reservoir,
- that the reservoir filter is clean and in good condition,
- that the H.P. pump is primed and there is no air leak on the suction side of the pump,
- that the release screw of the pressure regulator is correctly tightened,
- that sealing ball (2) is in position, (see Fig. I and II, page 5).

2 MA LOCATION OF THE ELECTRONIC CONTROL
510.00/3
UNITS AND RELAYS (All Models)
POSITIONING OF THE ELECTRONIC CONTROL UNITS AND RELAYS
No. Description Location
54 ABS Control Unit G
57 Fuel Calculator Unit A
60 Air Conditioning Control Unit A
76 Window Winder Unit F
80 Speed Regulating Unit E 81
Heater Control Unit A
84 Water Level Unit L
87 Water Temperature Unit B
89 Door Locking Warning Unit A
90 Door Lock Control Unit A 91
Remote Control door Lock Unit C
92 Interior Lighting Timer A
93 Bulb Failure Indicator Unit (Salopn) H
93 Bulb Failure Indicator Unit (Safari) J 110
Heater Plug Control Unit
,. K 127
Side lamp Audible Warning D 141
Ignition ECU K 142
Injection ECU E 151
Water temperature Flasher unit B 658
Blower Speed Control Unit E 731
Fuel Injection electronic Relay M 733
Air Cond. Engine Fan Relay K 734
Injector relay M 735
Main Beam Relay D
739 Height Control relay B 743
Air Horn Compressor Relay K 745
Blower Motor Fast Speed Relay A 750
Fog Lamp Relay
6 756
ABS Electra-Valve Relay L 757
ABS Protection Relay L 772
Blower Fan Motor 2nd Speed Relay K 773
Engine Cooling Fan lnverter Relay K 775
Starter Motor Safety Relay (Auto G/Box) B 778
Fuel Heater/Starter Motor Relay (with diode) K
779 Fuel Heater Oil pressure Relay (with diode) K 781
Main fuel Heater Relay K RI
Engine Cooling Fan Relay B R2
Front Window Winder Relay 6 R3
Rear Window Winder Relay B R4
Heated Rear Screen Relay 6 I
Windscreen Wiper Timer Relay
B
C Direction Indicator Unit B

ARRANGEMENT OF THE ELECTRICAL INSTALLATION
a @ CX25GTI 7185-t MA ’ 510.00/11
REP.
DESCRIPTION LOCATION
Crrcurt Wrnng CONNECTOR
Number HARN ES:
Channel-colour (or unit)
1 Front lighter and lrghtrng
crgar 172-186 15 3B-1 V H
10 Alternator
86 to 89
b6 Ilc & IN M & CA
44 Dtgital display
67 to 74 f5 l5V BA
45
Battery
2
b8 IN & IN
CP & CN
46 Instrument panel
63 to 108 g6 *
T
51 Ignition coil cyls 1 & 4
57-58 c6 . 3N Z
52 lgnrtion coil cyls 2 & 3
61-62 c6 3N Z
57 Fuel metering unit (option)
47-48 i5 4B 0
60 Air conditioning control unit (option)
12 to 15
h5 7B Q
81 Interior heating control unit
27 to 30 h5 8N K
84 Coolant level indicator unit
76 to 78 e4 56 D

89
Door locking indicator lamp unit
166-167
j5 5N H
90 Door locking control unit
159 to 169 j5 9v H
91
Remote control door locking unit
155 to 157
n5 8N P
92 Interior lighting timer
152 to 156 j5 7M H
93 Bulb failure detectron unit
33-109-I 10, 81 fo 83, 139. 191-200 s8 38 6B 6J L & 2xw
95 Junction/fuse box *
27 Side lamp audible warning 9 ?. *
*
157-l 58
g6 5N T
31
Flywheel datum sensor
60-61 c6 2M
Z
32 Flywheel teeth sensor
58-59 d6 2BI 2.
36 Ignition vacuum sensor
59 to 61 e3 30r CD
40 Mileage sensor (option)
50 e7 28 0
41 IEI control unit
54 to 65 e8 15B-15N Z
42 Injection electronic control unit
39 to 49 93 25N IC
70 Boot light switch
171 s6 1M + 1 E
74
Boot door locking switch
166 t5 2M
C
BO
Reversing lamp switch 33
d6 IN-1V
G
B5 Stop lamp switch
139 h6 IN-TM H
90 Hand brake switch
90
k5 2M H
92 Throttle spindle switch
45 to 47 b4 3N IC
29 lgnrtion switch
5-27, 38-130 h7 4M-48 95
30
L/H front door switch 154
f9 IM H
31 R/H front door switch
155
fl IM H
32 L/H rear door switch
157
k9 IM H
33 R/H rear door switch
158 kl 1M H
34
Glove box switch
170
f3 2xllc
H
35 Hydraulic fluid low pressure switch
81 e6 IM
G
$6
Hydraulic fluid level swatch
80 e8 1 Ic-1 M
G
$7
Coolant low level switch
76-77 e3 3R
D
* Particular Specification
8531-8532