Fiat 1998 Marea Weekend, Service Manual

Page: 168 / 846

Engine
Fuel system
Marea-Marea
Weekend^i
6v
1998 range
10.
Wiring connector
The numbers in boxes indicate the corre-
sponding control unit pins.
Pin A - Earth
Pin B - Positive
Pin C - Signal
Checking resistance
Sensor resistance may be measured as fol-
lows
- by connecting an ohmmeter across sensor
pins A and B to check fixed resistance is
1200 ohms;
- by connecting an ohmmeter across sensor
pins A and C and checking that resistance
changes from 0 to 1200 ohm ±20%. when
the throttle valve is moved.
Recovery
A value calculated on the basis of rpm and in-
ake manifold pressure is assumed. If the pres-
sure sensor also fails, a throttle opening angle
of 50° is adopted as a fixed value.
The strategy of gradually decreasing rpm
when idling (dashpot) is blocked.
Idle self-adaptation is blocked.
Mixture concentration self-adaptation is
blocked.
Removi ng - ref itti ng
Disconnect electrical connection, unscrew
both retaining screws and remove the sensor.
NOTE The potentiometer is fitted to the
throttle body by two tabs containing
two unslotted holes. No angular po-
sition adjustment is therefore neces-
sary because the control unit uses its
own self-adaption software to detect
whether the throttle is fully open or
fully closed.
NOTE Fit new potentiometer retaining screws each time they are removed because the thread is cov-
ered by a light coat of loctyte. This ensures a seal once only.
34
Publication no. 506.763/09