Throttle Position Sensor (Tps); Testing And Replacing; Engine Coolant Temperature (Ect) Sensor - BMW 5251 Service Manual

Fuel Injection
-
If voltage is present as described above, check wiring be-
tween ECM and valve. If no wiring faults are found, check
ECM signal to valve.
-
When replacing idle speed control valve, clean and inspect
all sealing areas.
.
Inspect sealing ring in throttle body and replace if neces-
sary.
Throttle position sensor (TPS),
testing and replacing
The throttle position sensor (arrow) is mounted on the side
of the primary throttle housing and is directly connected to
the throttle valve shaft. The ECM sends a voltage signal to
the potentiometer-type sensor and monitors the voltage that
comes back. Resistance decreases (voltage increases) as
the throttle opens.
NOTE-
Do not confuse the TPS on the primary throttle housing with
the throttle switch on the ASC secondary throttle housing.
4
Check throttle position sensor function by disconnecting har-
ness connector and checking across terminals. If any faults
are found, replace throttle position sensor.
Engine coolant temperature (ECT) sensor,
testing and replacing
Throttle position sensor
(M62
engine)
The ECT sensor is located on the front of the engine in the
coolanVthermostat flange.The ECTsensor is a dual tempera-
ture sensor. One circuit provides coolant temperature infor-
mation to the ECM while the other circuit provides coolant
temperature information to the instrument cluster.
The ECM determines the correct ignition timing and airlfuel
mixture required for the engine by monitoring an applied volt-
age (5 vdc) to the sensor. The voltage drop across the sensor
Test value
5
vdc (approx.)
4.0
kR(approx.)
Continuously variable
from
1.0
to
4.0
kR
without interruption
Test conditions
Harness connector
disconnected,
ignition on
Harness connector
disconnected,
ignition on
Throttle plate
rotated from idle to
full throttle position
Test Terminal
Term.
1
at harness
connector and ground
Term.
1
and term.
3
at
sensor
Term.
1
and term.
2
at
sensor