1997 FIAT PUNTO Coolant temperature sensor

4A*2 Fuel system -
single-point
petrol Injection models
1.1b IAW Weber-Marelli multi-point injection (MPI) system (16-valve engines) J Fuel
tank
2 Fuel pump 3 Multi-purpose
valve
4 Safety
valve
5 Anti-reflux
valve
6 F/fter 7 Battery 8
EVAP
solenoid
9 Dual
relay
10 Ignition switch 111nertia switch
12
Air conditioning compressor
13
Fuse 14 Throttle position sensor

1$
idle control stepper motor 17 Ignition coils 18 Sparkplugs 19 Fuel
rail
20 Pressure regulator 21 Injectors
15
Intake air temperature/pressure 22 Coolant temperature sensor sensor 23 Lambda/oxygen sensor
24 Rpm and TDC sensor 25 Engine immobiliser control unit 26 Catalytic converter 27 IAW failure warning light 28 EVAP canister 29 ECU 30 Diagnostic socket 31 Rev counter
Problems with the system should therefore be referred to a Fiat dealer for assessment. Once the fault has been Identified, the removal/ refitting procedures detailed in the following Sections can then be followed.
Precautions

A


Warning: Many procedures In this Chapter require the removal of fuel lines and connections, which may result In fuel spillage. Before carrying out any operation on the fuel system, refer to the precautions given In Safety flrstl at the beginning of this manual, and follow them implicitly. Petrol Is a highly dangerous and volatile liquid, and the precautions necessary when handling it cannot be overstressed. Note that residual pressure will remain in the fuel lines long after the vehicle was last used, When disconnecting tny fuel line, first depressurise the fuel system {see Section 9).
2 Air cleaner and inlet system Sk - removal
and
refitting ^
Removal
1242 cc (8-valve) engines 1 Remove the air cleaner element as described In Chapter 1A. 2 Disconnect the outer section from the hot air tube and the Inlet air duct and remove it from the engine compartment. 3 If necessary remove the inlet air duct. 4 Disconnect the large and small breather hoses from the inner section of the air cleaner, then unscrew the retaining nuts and lift the section from the throttle body. 5 Recover the sealing ring. Check the nng for condition and renew it it necessary. 6 Wipe clean the inner surfaces of both the Inner and outer sections of the air cleaner,
1242 cc (16-valve) engines 7 Release the hose clip and disconnect the inlet air duct from the resonator (see illustration).
2.7 Release the hose clip and disconnect the inlet air duct from the resonator

4A*2 Fuel system -
single-point
petrol Injection models
b) Ensure that the injector retaining clips are securely seated c) Make sure the fuel supply and return hoses are correctly fitted as noted on removal, d) Check that all vacuum and electrical connections are remade
correcily
and securely. e) On completion check the fuel rail and injectors for fuel leaks.
Fuel pressure regulator Note: On J998 models onward, the fuel pressure regulator is an integral pad of the fuel pump and cannot be renewed separately. The following procedure applies to pre-1998 models only. Removal 17 Remove the air cleaner and inlet air ducts as described In Section 2. 18 Oepressurise the fuel system as described in Section 9. 19 Disconnect the vacuum hose from the port on the side of the regulator. 20 Extract the retaining clip and pull the pressure regulator out of Ihe fuel rail. 21 Remove the O-ring seal. Refitting 22 Refit the fuel pressure regulator by following Ihe removal procedure in reverse, noting the following points: a) Renew the O'ting seal and smear it with a little Vaseline before assembling. b) When fitting the retaining clip, use a suitable socket or metal tube (o press In the three anchorage points at Ihe same time. c) Refit the vacuum hose securely.
Idle control stepper motor
23 Refer to Chapter 4A.
Throttle potentiometer 24 Refer to Chapter 4A,
Intake air temperature sensor 25 Refer to Chapter 4A.
Manifold absolute pressure (MAP) sensor 26 Reler to Chapter 4A.
6.12a Disconnect the wiring connectors for the fuel injector harness ...
6.3 Disconnect the wiring connectors from the throttle potentiometer and the idle control stepper motor
Coolant temperature sensor 27 Refer to Chapter 4A. Crankshaft TDC sensor 28 Refer to Chapter 4A. Electronic control unit (ECU)
29 Refer to Chopter 4A.
Inertia safety switch 30 Refer to Chapter 4A. Fuel injection system relays 31 Refer to Chapter 4A.
6 Engine management system ^ components
(1242
cc,16-vatve S engines) - removal and refitting ^
Note: Refer to the warning given in Section t before proceeding.
Throttle body assembly
Removal 1 Remove the resonator, air cleaner and inlet air duct as described in Section 2. 2 Free Ihe accelerator inner cab 6.12b ... and intake air temperature/pressure sensor
4 Slacken and remove the three bob j securing the throttle body assembly to ite inlet manifold. Ihen remove the assent?/ along with its insulating spacer. As the
throaii 1-
body is withdrawn, disconnect the vacuum hose from the underside of the unit. Refitting 5 Refitting is a reversal of the removal pi>: cedure, bearing in mind the following pants a) Examine the insulating spacer for signs d damage, and renew if necessary. b) Ensure the throttle body, inlet
manddd
and insulating spacer mating surfaces at -clean and dry. then fit the throttle
btxty
and spacer, and securely tighten the retaining bolts. c) Adjust Ute accelerator cable as desciter /nSecfw?4.
Fuel rail and injectors
Removal 6 Disconnect the battery negative termrul; (refer to Disconnecting the battery in ir*J Reference Section ol this manual), 7 Remove the resonator, air cleaner arid io«l 1 air duct as descnbed in Section 2. 8 Free the accelerator Inner cablc from l>*
1
throttle cam, remove the outer cable sprig. clip, then pull the outer cable out from
>H
mounting bracket rubber grommet, 9 From the side of the throttle bod/, | disconnect the wiring connectors from Ihs: throttle potentiometer and the idle cofttro^ stepper motor. 10 Oepressunse the fuel system si ' described in Section 9. ' 11 Loosen the clips or release tho quick-. release couplings and disconnect the fuel MdJ' and outlet hoses from the left-hand end oftfu fuel rail, below the throttle body. Note IM fitted positions ol the hoses to aid relirtirf i later. Undo the support bracket retaining bol and move the fuel hoses to one side. 12 Disconnect Ihe wiring connectors forth* fuel injector harness and the Intake an temperature/pressure sensor (m illustrations). 13 Disconnect the fuel pressure regulator-! vacuum hose and the EVAP purgo vaive h«* (see illustrations).
6.13a Disconnect the fuel pressure regulator vacuum hose...

4A*2 Fuel system -
single-point
petrol Injection models
6.13b ... and tho EVAP purge valve hose
14 Undo the two bolls securing the plastic nlet manifold upper section to the lower section. Release the spark plug HT lead from Ihe location groove in the manifold upper section, then lift the upper section, complete with throttle body, off the engine (see illustrations). Recover the O-nngs from the manifold ports. 16 Unscrew the two bolts securing the fuel rail assembly to the Inlet manifold lower section, inen carefully pull the injectors from ttie inlet manifold (see Illustration). Remove
tt>e
assembly from the engine and remove the injector lower O-ring seals. t& The injectors can be removed individually from the fuel rail by disconnecting the wiring connector, extracting the relevant metal clip
ano
easing the injector out of the rail. Remove themjector upper O-ring seals. 17 Check the electrical resistance of the tractor using a multimeter and compare it with the Specifications. Note: If a faulty Rector fc suspected, before condemning Wie
Rector,
it is worth trying the effect of one of m
proprietary
injector-cleaning treatments. Refitting
15 Refit the injectors and fuel rail by following tie removal procedure, In reverse, noting the Mowing points:
4} Re/few
the Injector O-ring seals, and
smear
them with a little Vaseline before assembling. Take care when fitting the
injectors
to the fuel rail and do not press
them
in further than required to fit the
retaining
clip otherwise the O-ring
seal may
be damaged.
6.14a Undo the inlet manifold upper section retaining bolts ... b) Ensure that the injector retaining clips are securely seated. c) Renew the sealing O-nngs fitted between the manifold upper and lower sections if in any doubt about their condition. d) Make sure the fuel supply and return hoses are correctly fitted as noted on removal. e) Check that all vacuum and electrical connections are remade correctly and securely. f) On completion check the fuel rail and injectors tor fuel leaks.
Fuel pressure regulator
Removal 19 Remove the resonator, air cleaner and inlet air ducts as described In Section 2. 20 Depressurise the fuel system as described In Section 9. 21 Disconnect the vacuum hose from the port on the side of the regulator. 22 Extract the retaining clip and pull the pressure regulator out of the fuel rail. 23 Remove the O-ring seal. Refitting 24 Refit the fuel pressure regulator by following the removal procedure in reverse, noting the following points: a) Renew the O-ring
seaJ
and smear it with a little Vaseline before assembling. b) When fitting the retaining clip, use a suitable socket or metal tube to press in the three anchorage points at the same time. c) Refit the vacuum hose securely.
Idle control stepper motor 25 The idle control stepper motor is an Integral part of the throttle body and cannot be individually renewed.
Throttle potentiometer 26 The throttle potentiometer Is an integral part of the throttle body and cannot be individually renewed.
Intake air temperature/pressure sensor
Removal
6.14b ... and lift off the manifold upper section and throttle body 28 Disconnect the sensor wiring connector, located on the right-hand side of the Inlet manifold upper section. 29 Undo the two screws and remove the sensor from the manifold. Refitting 30 Refitting is a reversal of the removal procedure. Coolant temperature sensor 31 Refer to Chapter 4A.
Crankshaft TDC sensor 32 Refer to Chapter 4A.
Electronic control unit (ECU)
Removal Note: 77?e engine management system has a learning capability which allows the ECU to store details of the engine's running characteristics in Its memory. This memory will be erased by the disconnection of the battery cables, with the result that the engine may idle roughly, or lack performance for a while, until the engine's characteristics are re-learnt. 33 The ECU (electronic control unit) is located on the right-hand inner wing panel. 34 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). 35 Undo the mounting bracket nuts and withdraw the unit from the inner wing (see Illustration). 36 Disconnect the ECU wiring connector, then remove the unit from the engine compartment.
6.15 Fuel rail securing bolts (arrowed) 27 Remove the resonator, air cleaner and inlet air duct as described in Section 2. 6.35 Undo the mounting bracket nuts and withdraw the ECU from the inner wing

4A*2 Fuel system -
single-point
petrol Injection models
Refitting 37 Refitting Is a reversal of removal making sure that the wiring connector is securely reconnected.
Inertia safety switch 36 Refer to Chapter 4A, Fuel injection system relays Removal 39 The fuel injection system twin relay Is located under a plastic cover on the engine compartment bulkhead. 40 The main purpose of the relay Is to supply current to the fuel pump, ignition coils, oxygen sensor, Injectors and EVAP solenoid. The relay is controlled by the ignition switch. A15 amp fuse, protecting ihe fuel pump, oxygen sensor and EVAP solenoid is located adjacent to the relay. 41 Remove the cover and pull the relay directfy from Its socket. Refitting 42 Refitting is a reversal of removal.
7 Fuel pump and fuel gauge sender unit - JK removal
and
refitting ^
Removal Note: Refer fo (he warning given in Section 1 before proceeding. 1 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). 2 Depreasurise the fuel system as described in Section 9. 3 Remove the rear soat as described In Chapter 11. Prise the fuel pump access cover out of the floor panel to gain access to the pump unit. On later models, undo the three retaining screws to release the cover. 4 Disconnect the wiring connector. 5 Bearing In mind the warning given In Section t, disconnect Ihe fuel supply and, where applicable, the return lines from tho pump unit by pressing the tabs. Plug the ends of the lines or cover them with adhesive tape. 6 Using a suitable tool, unscrew the large ring nut and carefully withdraw the fuel pump/fuel tank sender unit assembly from the fuel tank, along with its sealing rtng. 7 If necessary, the unit can be dismantled and the pump and sender unit separated. If this is (he case, carefully note the correct fitted positions of all components while dismantling the unit, and use these notes on reassembly to ensure that all items are correctly fitted.
Refitting 8 Refitting is a reversal of the removal procedure using a new sealing ring. Prior to refitting the access cover, reconnect the battery, then start the engine and check the fuel line unlon(s) (or signs of i

Fuel
tank -removal and refitting
Refer to Chapter 4A.
9 Fuel injection system -depressurisatton
Note: Refer to the warning given In Section 1 before proceeding.

A


Warning: The following procedure will merely relieve the pressure In the fuel system • remember that fuel will still be present In the system components and take precautions accord-ingly before disconnecting any of them. 1 The fuel system referred to in this Section is defined as the lank-mounted fuel pump, tha fuel filter, the fuel rail, the fuel injectors, and the metal pipes and flexible hoses of the fuel lines between these components. All these contain fuel which will be under pressure while the engine Is running and/or while the Ignition is switched on. The pressure will remain for some time after the Ignition has been switched off. and must be relieved before any of these components are disturbed for servicing work. 2 Disconnect the battery negative terminal (refer to Disconnecting the battery In the Reference Section of this manual). 3 Have a large rag ready to cover the union to be disconnected and, if possible, place a con-tainer beneath the relevant connection/union. 4 Slowly loosen the connection or union nut (as applicable) to avoid a sudden release of pressure, and ensure that the rag is wrapped around the connection to catch any fuef spray which may be expelled. Once the pressure is released, disconnect the fuel line, and Insert plugs to minimise fuel loss and prevent the entry of dirt Into the fuel system. Note that on later models, quick-release fuel couplings are used on many of the fuel line connections. To release these couplings, depress the two clips on the side of the coupling while keeping the fuel line pushed In. With the clips depressed, slowly withdraw the fuel line from the coupling allowing the fuel pressure to release, then withdraw the fuel line fully.
10 Inlet manifold-removal
and
refitting
Note: Refer fo the warning given in Section 1 before proceeding.
1242 cc (8-valve) engines
Removal 1 Remove ihe throttle body assembly as described in Section 5.
2 Remove the fuel rail and injectors at described in Section 5. 3 Drain the cooling system ss described n Chapter 1A. 4 Disconnect the wiring connector from ih* coolant temperature sensor (situated on it* left-hand side of the manifold). 5 Undo the bolt securing the accelerator cable mounting bracket to the manifold, am position it clear of the manifold. 6 Slacken the retaining clip and disconnect the coolant hose from the rear of the mandold 7 Disconnect the brake vacuum hose, 6 Undo the seven manifold retaining nuisw bolts, and remove the manifold from tta engine. Remove the gasket and discard tti new one should be used on refitting. Refitting
9 Refitting is a reverse of the removjf procedure, noting the following points: a) Ensure that the manifold and cylinder lim mating surfaces are dean and
dry.
and fill new manifold gasket. Refit the
manifold
and securely tighten Its retaining
nuts.
b) Ensure all relevant hoses are recorwscfed fo their original positions and are
sacurtfy
held (Where necessary; by the
retaining
clips. c) Refit the fuel rail and injectors, and
the
throttle body assembly with
reference to
Sect/on 5. d) On completion, refill the cooling
system
as described in Chapter 1A. 1242 cc (16-valve) engines
Removal 10 Disconnect the battery negative ternnncf (refer to Disconnecting the battery in ths Reference Section of this manual). 11 Remove the resonator, air cleaner and inlet air duct as described In Section 2. 12 Drain the cooling system as described r, Chapter 1A. 13 Free the accelerator inner cable from IN throttle cam. remove the outer cable spring dip. then pull the outer cable out from itt mounting bracket rubber grommet. 14 From the side of the throttle boOf, disconnect the wiring connectors from the throttle potentiometer and the Idle contrd stepper motor. Disconnect the coolant temperature sensor wiring connector located in the Inlet manilold below the throttie bodr, and disconnect the brake servo vacuum hose. 15 Disconnect Ihe wiring connectors for the fuel in|ector harness and the Intake a* temperature/pressure sensor, thtn disconnect the fuel pressure regulator vacuum hose and the EVAP purge valve
hose
(see illustration). 16 Undo Ihe two bolts securing the plastic Inlet manifold upper section to the lower section. Release the spark plug HT lead from the location groove in the manifold upper section, then lift Ihe upper section, complete with throttle body, off the engine. Recover
the
O-rings from the manifold pons.

Automatic transmission 7B*3
11 When reverse gear Is selected, the control unit keeps the transmission In tow ratio, if this were not the case, it would, In theory, be possible to drive as fast In reverse as in forward gear. 12 An electronic control unit supplies the current to energise the clutch. The control unit receives signals concerning engine speed, road speed, accelerator pedal position, and gear selector position, Sensors include the following. a) Engine rpm sensor (from the Injection/ignition control unit) b) Accelerator pedal switch
c) Throttle valve position sensor d) Selector lever position sensor e) Vehicle speed sensor f) Coolant temperature sensor g) Air conditioning sensor h) Brake switch I) Torque signal
13 The final drive/differential unit Is conventional. Drive from the driven pulley is transmitted to the differential by an Intermediate reduction gear. 14 The ECVT incorporates a warning light which illuminates when a fault occurs.
Precautions 1$ Observe the following precautions to avoid damage to the automatic transmission: a) Do not attempt to start the engine by pushing or towing the car. b) If the car has to be towed for recovery, the distance must not exceed 12 miles (20
km),
and the speed must not exceed
19
mph
(30 kph).
If these conditions cannot be met, or If transmission damage is suspected, only tow the car with the front wheels clear of the ground. c) Only engage P or R when the vehicle is stationary.
1.1b Electromagnetic f Coil 2 Signal from vehicle speed sensor 3 Transmission 4 Electromagnetic powder 5 Drive shaft (driven by crankshaft) $ Transmission input shaft 7 Electromagnetic clutch housing 8 ECVT control unit
clutch control system 9 Accelerator pedal micro switch 10 Throttle
vafve
opening position potentiometer 11 Multifunction switch 12 Ignition switch
13
Air conditioning
signal
14 Engine PPM
signal
15 Accelerator pedal 16 Coolant temperature signal 17 Injection/ignition control unit 18 8attery
1.1c Hydraulic control system 3 Injection/ignition control unit 4 Air conditioner sensor
signal
6 Coolant temperature signal 7 Clutch signal 8 Engine RPM
signal
9 ECVT warning light 10 Selector lever position 11 Accelerator
pedal
switch/throttle
valve
potentiometer/torque signal 12 Brake switch 13
ECVT
control unit 14 Signal from vehicle speed sensor
15
Accelerator pedal position switch
16 Pulley ratio 17 Input shaft RPM 18 Primary oil pressure
19
Primary pulley 20 Electromagnetic clutch 21 Pressure regulating solenoid valve 22 Oil pressure control valve 23 Secondary oil pressure 24 Slip ring 25 Drive from engine 26 Oil pump 27 Vehicle speed sensor 28 Secondary pulley 29 Belt and pulley 30 Drive to drlveshafts