Suzuki GF60A, Service Manual

Page: 89 / 336

Engine Electrical Devices: 1C-2
• The CMP sensor is a GMR (Giant Magnet Resistive)
semiconductor type sensor.
The GMR semiconductor has the property of varying
the electrical resistance depending on the intensity of
the magnetic force applied.
When the line of magnetic force from the magnet to
the GMR semiconductor is increased or decreased,
the electrical resistance of the GMR semiconductor
will change. The changes in resistance as the
magnets pass create the sensors waveform.
When a trigger vane on the camshaft reluctor aligns
with the sensors internal magnet, the electrical
resistance of the GMR will decrease.
When a trigger vane moves away from the sensor, the
electrical resistance of the GMR will increase.
When the GMR semiconductor voltage becomes
higher than the standard value, the sensors signal will
be lower. And when the voltage becomes lower than
the standard value, the sensors signal will be higher.
The nine camshaft trigger vanes provide nine high
voltage signals from the CMP sensor to the ECM
during one camshaft rotation (two rotations of
crankshaft).
• Failure symptom:
Without the CMP sensor signal input, the ECM does
not output the ignition and fuel injection signals.
• ECM cylinder identification:
The cylinders are identified by a calculation of two
signals; one from the CKP sensor and one from the
CMP sensor.
The ECM measures the time interval of the signals
inputted from the CKP sensor.
When the ECM detects a signal interval that is longer
than normal, it determines that the wide space
between the reluctor bars (30 degree spaced apart
section) has passed through the CKP sensor.
When this wide space passes the CKP sensor, the
ECM identifies the cylinder position according to the
number of inputs and the input timing (pettern) of the
CMP sensor signal input passed through the
prescribed space before and after the wide space.
1. Camshaft 4. Magnet
2. Trigger vane 5. CMP sensor
3. Magnet resistive semiconductor
Signal
High
Low
1
3
5
4
2
IAJ611130008-02
Cm.: Compression, Ep.: Explosion, Ex.: Exhaust, In.: Intake,
CKP sensor
signal
CMP sensor
signal
No.1 cylinder
No.3 cylinder
No.2 cylinder
TDC
Cm. Ep. Ex. In.
Cm. Ep. Ex. In.
TDC
Cm. In.
TDC
Ep. Ex.
30 signals / crankshaft 1 rotation
CMP sensor - 9 signals / 720° (crankshaft 2 rotation)
IAJ611130002-01