1988 CITROEN CX low oil pressure

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.

CHECKING THE IGNITION SYSTEM
USING CHECKING EQUIPMENT OUT 106 029T
The instrument can be utilised on CX 2400 I.E. with naturally aspirated engine and CX 2500 I.E. TURBO. Howe-
ver, on CX 2400 I.E. having an integrated electronic ignition system with a single connector E.C.U., it is neces-
sary to proceed as follows:
- connect the I.E.I. control unit to the black connector of OUT 105 029.T
- set the switch of the apparatus to the “1 connector” position
- I.E.I. with 1 or 2 sensors can be checked with this device.
a) Testing the ignition coil primary winding:
- The warning lamps, one at each coil, blink rythmically with the impulses transmitted to their primary win-
ding. Steady blinks indicate that there is enough current to generate a spark in the secondary winding.
- The switch situated under the warning lamps makes it possible for the primary windings of both coils to
be insulated, by pushing, in the “out of circuit“ position, any interference coming from the HT circuit when
the frequency of illumination for sensor warning lamps is checked.
- If the warning lamps blinking is correct, the failure may be caused by:
- the ignition information to the fuel injection control unit, (paragraph c),
- the secondary winding (coil wires, coils),
- any other item required for a correct operation of the engine such as injection, valve gear, rockers etc.) -
If the warning lamps blinking is not correct, examine the control unit warning lamps, (paragraph b),
b) Testing the sensors: -
The warning lamp connected with the “datum” sensor blinks rythmically with the impulses transmitted by
the peg, i.e. one blink per engine revolution, (2 sensors fitted).
- The warning lamp connected with the “flywheel pick up” sensor, blinks rythmically with the impulses sent ’
by the flywheel teeth.
The frequency of the flashes is such as they can hardly be seen.
Apparently, the lamp stays on, (1 or 2 sensors fitted).
On the CX 2400 I.E. and 2500 I.E. with normally aspirated engine, the vacuum pressure warning lamp lights
up momentarily after a sharp acceleration: this warning lamp is no longer usable on the CX 2500 I.E. with
turbocharger.
c) Tests related with the I.E.I. control unit:
E.C.U. functions: -
The rev. counter warning lamp blinks rythmically with the impulses transmitted to the rev. counter.
- The injection warning lamp blinks rythmically with the impulses sent to the fuel injection control unit
+k 8531

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).

REPAIR OF THE HYDRAULIC SYSTEM
FITTING PRECAUTIONS
5. PRECAUTIONS TO BE TAKEN BEFORE WORKING ON THE HYDRAULIC SYSTEM:
a) Carrefully clean the aera of work, the unions and the unit to be removed
- Disconnect the lead from the negative terminal of the battery.
- Only use petrol or lead-free petrol cleaning.
b) Release the pressure in the circuits:
- Place the vehicle in the K/OW~~ position.
- Slacken the pressure regulator release screw (by one turn to one turn and a half, do not remove the screw:
the sealing ball (21, see Fig. I and II page 5, could get lost,
- Wait until the front of the car has reached the low position. 6. PRECAUTIONS TO BE TAKEN DURING REMOVAL.
a) Blank off the metal pipes with plugs, and rubber tubes with round pins of the correct diameter
b) Blank off the openings of components with plugs of the correct diameter.
NOTE: Plugs and pins must be carefully cleaned before insertion 7. CHECK OR TEST OF HYDRAULIC UNITS:
- use 4034-T test bench equipped and designed for use with LHM fluid.
- This bench is painted green and its accessories are marked in green.
- Never use the bench with another fluid or for testing components operating with another fluid (units of a c(D))
car using LHS 2 for instance).
NOTE: The uLe Bozec)) pump used on test benches for checking DIESEL injectors can be resorted to for testing,
components operating with LHM mineral fluid provided that the bench is cleaned first. 8. PRECAUTIONS TO BE TAKEN DURING REFITTING.
a 1 Cleaning:
- steel pipes must be blown through with compressed air,
- rubber tubes and seals must be washed in petrol or lead-free petrol and then dried with compressed air,
- hydraulic units must also be cleaned with petrol or lead-free petrol and blown through with compressed air.
NOTE: Renew all joints and seals during refitting
b) Lubrication.
- Follow the indications as stated in the operations in the Manual.
- Joints and internal parts must be lightly oiled before fitting (use mineral fluid LHM only).
- If parts in contact with hydraulic units have to be greased, use a mineral grease only (as employed for cardan
shafts or bearings). +#+
8531-8532

Connectors
l.-~l
a,
- Connectors
,”
9 r, 75 Colour
FiY
E
vl
-
M
M
V
V
V
V
M
M
-
N
v
V
M
N
V
-
V
M
V
V
V
-
M
V
2
$
R
V
M
Mv
B
N
BI
B
Mv . -
z
Y
i
r”
B
G Function Function
:
m
.e-
1
-
1
2
3
-
1
2
3
4
1
2
3
4
I
2
3
4
-
1 .-
f
-
M
M
M
-
N
N
M
-
B
B
V
G
N
-
N
M
-
V
V
-
-
M 1
2
3
-
-
-
-
1
2 -
3 -
6 -
4 -
4 -
4 -
3
1
3
-
9
-
6
-
9
-
2
L.
B
-
J
-
v
-
V
-
B
m
sg
ZD
‘N
B
-
B
-
B
-
B
-
V
-
-
-
B Eng. Oil Pressure Sensor
94
95
96 Choke
Diesel Pre Heating
Front Bulb Failure 84
I 8
1
Eng. Oil Sensor
V
J
J Low Fuel Warning Lamp
Fuel Gauge
Fuel Transmitter Earth “Stop” Warning
Hydraulic Warning
Eng. Oil Low Pressure Warning
Water Low Level Warning
Water Temp. Warning
” + Ignition Switch
Battery Charge Warning
Eng. Oil Temp. Warning
Water Low Temp. Warning
2 74
80
79
77
73
80
89
70
100
102
101
98
99
97
85
90
211
212
214
103
103
9
10
11 Instrument Lighting
L/H Dir. Ind. Warning
Seat Belt Warning
+ Ignition Switch (After F2)
Earth 107
R/H Dir. Ind. Warning 105
106
85
211
108
65
66
65 BI
Mv
M
B
Mv
3
L/H Rear Door Warning
Boot Door Warning
R/H Rear Door Warning
L/H Front Door Warning
R/H Front Door Warning
Bonnet Door Warning + Ignition Switch (After F.2)
Earth
Diesel TDC
Tachometer
4
B
G Turbo Pres. Warning
Anti-knock Warning 64
63
Yelow Warning
Red Warning econoscope
5
Brake Pad Wear Warning
Hand Brake Warning
Rear Fog Lamp Warning
Side Lamp Warning
Dipped Beam Warning
Main Beam Warning
Clogged Filter Warning
0 ic 6
R Earth
Test
Warning Rear Bulb
Failure
Unit 81
82
83
7
12 ?ABS Warning
+ Ignition Switch ABS

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
q @ CX22TRS 7/85-t 1 MA 5 510.00110
3EF. DESCRIPTION LOCATION
Circuit Wiring CONNECTOR
Number HARNESS
Channel-colour (or urilt)
1 Front cigar ljghter & lighting 137-151
i5 38-l v H
5 Ignition distributor 30 to 34 3N 2
10 Alternator 51 to 54 b6 IN + Ilc CA & M
25 A & B Horn 107 - 108 c7 1N + 1N A
45 Battery 1
b8 IN + IN CP & CN
46 Instrument panel 36 to 73 159 to 162 g6 * T
50 Ignition coil 30-3 1 IN + Ilc G
75 Ignition module 30 to 32 7N Z
81 Interior heating control unit 21 to 24 h5 8N K
84 Coolant level indicator unit 41 to 43 e4 5B D
89 Door locking indicator lamp unit 131-132
i5 5N H
90 Door locking control unit 124 to 134 15 9v H
91 Remote control door locking unit “PLIP” 120 to 122 n5 8N P
92 Interior lamp timer 117 to 122 15 7M H
93 Bulb failure detection unit
27, 46 to 48, 74-75, 104-I 65 S8 38 + 68 & 6J L & w
95 Junction/Fuse box
127 Side lamp audible warning 1222123 g8
g6 5+N‘” ;
130 TDC sensor 28 3M
170 Boot light switch 136 s6 IM E
174 Boot door locking switch 126 t5 2M C
180 Reversing lamp switch 27 d6 1N + 1V G
185 Stop lamp switch 104 h6 IN + IM H
190 Hand brake switch 55 k5 2M H
!25 Carburettor choke switch 49 IG B
!29 Ignition switch 4-30, 44-95 h7 4M + 48 (95)
!30 L/H Front door switch *
119 f9 IM H
!31 R/H Front door switch 120 fl 1M H
!32 L/H rear door switch 122
k9 IM H
!33 R/H Rear door switch 123 kl IM H
!34 Glove box switch 135 f3 1 Ic+ 1 Ic H
!35 Hydraulic fluid low pressure switch 46 e6 IM G
!36 Hydraulic fluid level switch 45 e8 1 Ic + IM G
!37 Coolant low level switch 41-42 e3 3R D
!38 R/H Front door lock switch 64
jl 28 H
!39 L/H Front door lock switch 63 P
28 H
!41 R/H Rear door lock switch 66 (71 28 PD !42 L/H rear door lock switch 65 qg 28 PG
!43 Boot door lock switch 67 c5 2M C
!44 Bonnet lock switch 62 a5 2M V
!51 Height control switch 96 to 100
j5 2M & 4M H & (608) !54 Lighting/Direction indicator switch 72 to 75. 57 to 163 97 58 4M 3M T
!55 Windscreen wiper/Washer & Horn switch 90 to 95, 107 g6 48 5B 28 T
!68 Air recycling switch 15 to 17
h5 4J Q
!71 Air distribution switch 12 to 14 h5 4M Q !78 Blower motor speed control 18 to 20 h6 38 Q
!79 Heater control & Lighting 23 to 25-68 h4 58 K
100 Starter motor 2 to 4 b5 IN & IR CP 165 Ashtray lighting 152 if5 2B H
I70 Boot lighting 136 s4 1N & llc F
I75 Glove box lighting 135 f4 IN & 1M H I80 Engine compartment lighting 150 c6 IN EC
I85 L/H rear number plate lighting 166 t6 Ilc + IM E 186 R/H rear number plate lighting 167 t4 Ilc + IM E
190 Steering lock lighting 156 97 Ilc + IIC T
L20 Carburettor idle cut-out solenoid 25 IN M L30 L/H front brake caliper 48-49 d9 2N + IN U(g.) I31 R/H front brake caliper 50-51 dl 2N + IN U(d.!
L40 L/H front side lamp 149 a8 2M G
141 R/H front side lamp 151 a2 2M D 142 L/H rear lamp 165 L43 R/H rear lamp 166 I45 L/H rear lamp cluster t8 6G F
146 R/H rear lamp cluster t2 6G F
157 L/H stop lamp 104
* Particular Specification
8531-8532

6 ARRANGEMENT OF THE ELECTRICAL INSTALLATION
CX
22 TRS 7185 --)
REF DESCRIPTION LOCATION
“;;;;;roR HARNES:
Circuit Wiring Channel-colour (or unit)
458 R/H stop lamp 105 460 L/H rear fog lamp 156 461 R/H rear fog lamp 157
462 L/H reversing lamp 27
463 R/H reversing lamp 28
470 Fuse l 480 g8 L/H front direction indicator 73 a7 30r G 481 R/H front direction indicator 76 a3 30r D 482 L/H rear direction indicator 74
483 R/H rear direction indicator 75
486 L/H long range lamp connector 159 a7 28 G 487 R/H long range lamp connector 164 a3 2B D 488 L/H headlamp 160-161 a8 3lc G
489 R/H headlamp
162-l 63 a2 3lc D 500 L/H front loudspeaker connections 139
gg IB + IR H 501 R/H front loudspeaker connections 141
gg IB + IR H 502 L/H rear loudspeaker connections 142 k9 28 PG 503 R/H rear loudspeaker connections 147 kl 28 ‘,PD 506 L/H front tweeter connections 140 h9 2B H 507 R/H front tweeter connections 140 hl 28 H
511 Rear fog lamp switch 156 to 158 g5 881 B 519 L/H window motor switch on driver’s door 85 to 87 h9 5B PC ‘520 R/H window motor switch on driver’s door 80 to 82 h9 5M PC 521 L/H window motor switch on passenger’s door 85 to 87 hl 58 PP 532 Heated rear screen switch 110 to 112 j5 5M P 545 Interior lighting switch
114 to 116 j5 58 P 570 Hazard warning switch 75 to 78
g5 8N B 580 Fuel gauge transmitter 59 to 61
96 IM 1N IJ J 600 Windscreen wiper motor 90 to 94 e4 58 D 608 Height control motor 97 to 103 j4 ‘. 38 H 615 R/H front window motor 80-81
gg 30r LV 616 L/H front window motor 85-86
gl 30R PP 621 Air intake motor 15-16 e3 2B Q 622 Air distribution motor 13-14
94 28 0 625 R/H front door lock motor 125-127
0 ZM-3B H 626 L/H front door lock motor 128 to 131 jl ZM-3B H 627 R/H rear door lock motor 125 to 127 p9 2M-3B PG 628 L/H rear door lock motor 128 to 131 pl 2M-3B PD 629 Boot door lock motor 131
t5 2B C 630 Fuel flap lock motor 127 s2 28 X 635 Engine cooling fan motor 11 a6 IM-IR V 640 Clock 32 to 34 f5 4M BA 650 Engine oil pressure switch 44 d3 IM RC 658 Blower fan speed control module 20 f3 1 V-l BI Q 680 Windscreen washer pump 95 el 2N D 690 Central interior lighting 113 to 115 n5 1N+2xllc+lM P 695 Front interior spot lamp 113 n5 lN-1M P 698 Headphone socket 143 to 146 k5 58 H 710 12 V supply soket 89 k5 IN + IM H 721 Radio connections t 12V and loudspeakers) I” + ” - &, LS) 139 to 147 k5 lR+4x2B H 727 Carburettor mixture heating element 7 IIC RM 735 Main beam relay 163-164 q7 5N T 739 Height control relay 98 to 102 f7 5N H 745 Blower motor fast speed relay 18 to 20
94 5N Q 778 Mixture element temperature relay 5 to 7 5lc RC 779 Mixture element engine running relay 8-9 5lc RC 781 Mixture element engine starting relay 6-7 5N RC 788 Engine cooling fan resistance 11 38 V 795 Lighting rheostat 62 g6 4B B 810 L/H direction indicator repeater connectrons 72 e9 II&l + IICT G 811 R/H direction indicator repeater connections 77 el II&l + IICV D 831 Interior temperature selection motor 21 to 25
cl5 5B K 836 Oil level sensor 57-58 c4 28 M 839 Interior air temperature sensor 24
j5 28 P 850
2 stage engine cooling fan thermal switch 11-12
b6 3lc V 853 Mixture element temperature thermal switch 5 IJS + IJti RM 855 Max. coolant temperature thermal switch 39 c4 IB M 935 Blower motor 19 d5 IN + li;j Q 945 Heated rear screen 111 r3 to 7 IN + IN F + ML 980 Door locked warning lamp 132
99 Ilc + Ilc H