CAMSHAFT POSITION
SENSOR
DESCRIPTION
The camshaft position sensor is mounted on the
cylinder head cover (Fig. 13). The sensor detects the
camshaft position by a contactless signal (hall effect).
The electronic control module (ECM) detects TDC
position of cylinder 1 by means of the signal supplied
by the camshaft sensor. Injection timing is synchro-
nized by means of the camshaft signal and the crank-
shaft signal.
OPERATION
The signal circuit of the camshaft sensor has a
voltage
of
approximately
5V.
If
the
segment
machined into the exhaust camshaft sprocket is posi-
tioned opposite the camshaft sensor, the camshaft
signal is approximately 0V. This 0V to 5V signal is
used by the engine control module (ECM) for detect-
ing ignition TDC of cylinder 1 as the engine rotates.
If no signal is supplied by the camshaft position sen-
sor, the vehicle will not start.
REMOVAL
(1) Disconnect negative battery cable.
(2) Remove engine cover (Refer to 9 - ENGINE
COVER - REMOVAL).
(3) Disconnect camshaft position sensor electrical
connector.
(4) Remove retaining bolt and remove sensor from
cylinder head cover.
INSTALLATION
(1) Install camshaft position sensor into cylinder
head cover.
(2) Connect electrical connector.
(3) Install engine cover (Refer to 9 - ENGINE
COVER - INSTALLATION).
(4) Connect negative battery cable.
MANIFOLD AIR FLOW (MAF)
SENSOR
DESCRIPTION
The miromechanical Mass Air Flow (MAF) sensor
is a hot film thermal flowmeter with an integrated
temperature sensor which detects the intake air tem-
perature. The sensor is designed for recording load
on combustion engines with diesel fuel injection and
has a cylinder size in accordance with the required
air flow rate. The MAF Sensor is mounted inline in
the air intake between the air filter and the turbo-
charger (Fig. 14).
OPERATION
The MAF sensing element consists or two temper-
ature sensors symmetrical to a heating area sitting
on a thin membrane. Up and down stream sensors
see the same temperature when there is no air flow-
ing through the sensor. With incoming flow, the
upstream heating area is cooled down due to heat
transfer, while the downstream area retains it’s tem-
perature because the air has been heated up after it
Fig. 13 ENGINE COMPONENT LOCATIONS
1 - CAMSHAFT POSITION SENSOR
2 - INJECTION PUMP
3 - POWER DISTRIBUTION CENTER (PDC)
4 - EGR VALVE
Fig. 14 MASS AIR FLOW (MAF) SENSOR
14 - 26
FUEL INJECTION
PT