Toyota Celica 2005, Repair Manual

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A21566
G and NE Signal Waveforms
G
NE
NE
5 V
/Division
20 msec./Division (Idling)
10 msec./Division (Idling)
G
5 V
/Division
DI − 482
− DIAGNOSTICS ENGINE (2ZZ − GE)
2005 CELICA (RM1131U)
DTC P0340 Camshaft Position Sensor ”A” Circuit
(Bank 1 or Single Sensor)
DTC P0341 Camshaft Position Sensor ”A” Circuit
Range/Performance (Single Sensor)
CIRCUIT DESCRIPTION
The camshaft position sensor (G signal) consists of a magnet iron core and pickup coil.
The G signal plate has 3 teeth on its outer circumference and is installed on the camshaft timing pulley.
When the camshafts rotate, protrusion on the signal plate and the air gap on the pickup coil change, causing
fluctuations in the magnetic field and generating voltage in the pickup coil.
The NE signal plate (crankshaft timing pulley) has 34 teeth and is installed to the crankshaft. The NE signal
sensor generates 34 signals at every engine revolution. The ECM detects the crankshaft angle and the en-
gine revolution based on the NE signal, and the cylinder and angle of VVT based on the combination of the
G and NE signal.
DTC No. DTC Detection Condition Trouble Area
P0340
S
No camshaft position sensor signal to ECM during cranking
(2 trip detection logic)
S No camshaft position sensor signal to ECM at engine speed
600 rpm or more (1 trip detection logic)
S Open or short in camshaft position sensor circuit
S Camshaft position sensor
S Camshaft timing pulley
S Timing chain has a jumped tooth
S ECM
P0341
While crankshaft rotates twice, camshaft position sensor signal
is input to ECM 12 times or more (1 trip detection logic)
S
Hint:
Under normal condition, the signal from the sensor is regular-
ly input into the ECM 3 times per 2 engine revolutions
Reference: Inspection by using the oscilloscope.
HINT:
The correct waveform is as shown on the left.
Item Contents
Terminal
CH1: G+ − NE −
CH2: NE+ − NE −
Equipment Setting 5V/Division, 20ms/Division
Condition During cranking or idling
DIC7I − 02
680