CIRCUIT INSPECTION
DTC 12 RPM Signal Circuit (No. 1)
CIRCUIT DESCRIPTION
The distributor in the Engine Control System contains three pick–up coils (G1, G2 and NE).
The G1, G2 signals inform the ECM of the standard crankshaft angle.
The NE signals inform the ECM of the crankshaft angle and the engine speed.
Code No. Diagnostic Trouble Code Detecting Condition Trouble Area
12
No “NE” or “G1” and “G2” signal to ECM within 2 sec.
after cranking.
Open or short in NE, G circuit.
Distributor
p
en or short in STA circuit
Open in “G ” circuit.
Open or short in STA circuit.
ECM
Reference INSPECTION USING OSCILLOSCOPE
During cranking or idling, check between terminals G1,
G2, NE and G of ECM.
HINT: The correct waveforms appear as shown in the
illustration on the left.
EG–354
–ENGINE TROUBLESHOOTING CIRCUIT INSPECTION
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