Dtc 12 Crankshaft Position Sensor Circuit Malfunction
DTC 12 Crankshaft Position Sensor Circuit Malfunction
DESCRIPTION
The crankshaft position sensor in the engine control system contains a signal plate and a pickup coil for the TDC signal. The TDC signal plate has 1 tooth on its outer circumference. The TDC signal sensor generates 1 signal for every crankshaft revolution. The ECM detects the top dead center position based on the TDC signal.
| DTC Code | DTC Detection Condition | Trouble Area |
| 12 | No TDC signal is sent to the ECM at 400 rpm or more. | Open or short in crankshaft position sensor circuit
Crankshaft position sensor
ECM
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WIRING DIAGRAM
INSPECTION PROCEDURE
| 1.INSPECT CRANKSHAFT POSITION SENSOR |
Inspect the crankshaft position sensor (See page ).
| | REPLACE CRANKSHAFT POSITION SENSOR
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| 2.CHECK ECM (TDC, NE SIGNAL) |
While cranking or idling, check the waveforms according to the value(s) in the table below.
- OK:
| Tester Connection | Condition | Specified Condition |
| C101-17 (TDC+) - C101-16 (TDC-) | Idling | Correct waveform is as shown |
| C101-19 (NE+) - C101-18 (NE-) | Idling | Correct waveform is as shown |
Text in Illustration| *a | Component with harness connected
(ECM) |
| *b | TDC and NE Signal Waveforms |
| 3.CHECK HARNESS AND CONNECTOR (ECM - CRANKSHAFT POSITION SENSOR) |
Disconnect the crankshaft position sensor connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard Resistance (Check for Open):
| Tester Connection | Condition | Specified Condition |
| C109-1 - C101-17 (TDC+) | Always | Below 1 Ω |
| C109-2 - C101-16 (TDC-) | Always | Below 1 Ω |
- Standard Resistance (Check for Short):
| Tester Connection | Condition | Specified Condition |
| C109-1 or C101-17 (TDC+) - Body ground | Always | 10 kΩ or higher |
| C109-2 or C101-16 (TDC-) - Body ground | Always | 10 kΩ or higher |
Reconnect the crankshaft position sensor connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
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| OK | |
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| CHECK FOR INTERMITTENT PROBLEMS
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