Crankcase emission control

1 The crankcase emission control system of Fiat Punto consists of a hose from the camshaft cover/cylinder head extension to the air cleaner (or inlet duct).
2 The system requires no attention other than to check at regular intervals that the hose is free of blockages and undamaged.

Evaporative emission control

3 The evaporative loss emission control system of Fiat Punto consists of the control solenoid, the activated charcoal filter canister and connecting fuel vapour hoses.

Control solenoid renewal

SOHC (8-valve) engines

4 Disconnect the battery negative terminal.
5 Remove the air cleaner assembly.
6 Disconnect the wiring connector and fuel vapour hose from the control solenoid (see illustrations).



Disconnect the wiring connector ...



... and fuel vapour hose from the control solenoid - SOHC (8-valve) engines


7 Extract the retaining spring clip, and remove the solenoid from the inlet manifold of Fiat Punto (see illustrations).



Extract the retaining spring clip ...



... and remove the solenoid from the inlet manifold - SOHC (8-valve) engines


8 Refitting is a reversal of removal.

DOHC (16-valve) engines

9 Disconnect the battery negative terminal.
10 Remove the air cleaner assembly of Fiat Punto.
11 Disconnect the wiring connector and fuel vapour hose from the control solenoid (see illustration).



Disconnect the wiring connector (A) and fuel vapour hose (B) from the control solenoid - DOHC (16-valve) engines


12 Undo the two retaining screws and remove the solenoid from the inlet manifold (see illustration).



Undo the two retaining screws (arrowed) and remove the solenoid from the inlet manifold - DOHC (16-valve) engines


13 Refitting is a reversal of removal.

Charcoal canister renewal

14 Firmly apply the handbrake of Fiat Punto, then jack up the front of the car and support it securely on axle stands. Remove the right-hand front road wheel.
15 Working under the right-hand wheel arch undo the retaining screws and remove the wheel arch liner main and centre panels for access to the charcoal canister.
16 From within the engine compartment. disconnect the two fuel vapour hoses at their quick-release fittings adjacent to the right-hand suspension strut tower.
17 Working under the wheel arch, undo the retaining nut and bolt, and remove the canister and vapour hoses from under the car Fiat Punto.
18 Refitting is a reversal of removal.

Exhaust emission control

Catalytic converter renewal

19 The catalytic converter is an integral part of the exhaust manifold.

Lambda sensors renewal

Note: The lambda sensors are delicate and will not work if dropped or knocked, if their power supply is disrupted, or if any cleaning materials are used on them.
20 The two sensors are threaded into the exhaust manifold - one 'upstream' and one 'downstream' of the catalytic converter.
21 Disconnect the battery negative terminal.
22 Remove the air cleaner assembly.
23 Firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands.
24 Undo the four bolts securing the heat shield to the exhaust manifold of Fiat Punto.
25 From under the car, undo the three nuts securing the heat shield to the catalytic converter, then remove the heat shield from the manifold.
26 Disconnect the relevant sensor wiring connector located on the transmission bellhousing (see illustrations).



Upstream lambda sensor wiring connector (arrowed)



Downstream lambda sensor wiring connector (arrowed)


27 Unscrew the sensor in Fiat Punto engine, taking care to avoid damaging the sensor probe as it is removed.
Note: As a flying lead remains connected to the sensor after it has been disconnected, if the correct spanner is not available, a slotted socket will be required to remove the sensor.
28 Apply a little anti-seize grease to the sensor threads - avoid contaminating the probe tip.
29 Befit the sensor to the downpipe.