Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC Description
ECM supplies a voltage of 5 V to some of the sensors systematically divided into 2 groups, respectively. Accordingly, when a short circuit develops in a sensor power source, a malfunction may occur simultaneously in the sensors belonging to the same group as the short-circuited sensor.
Sensor power supply 1
- Crankshaft position sensor 1
- Intake camshaft position sensor (bank 1)
- Exhaust camshaft position sensor (bank 1)
- Throttle position sensor
- Mass air flow sensor
- Accelerator pedal position sensor 1
- Engine oil pressure sensor
- Battery current sensor
- Power steering pressure sensor
Sensor power supply 2
- Crankshaft position sensor 2
- Fuel rail pressure sensor
- Intake manifold runner control valve position sensor
- Intake camshaft position sensor (bank 2)
- Exhaust camshaft position sensor (bank 2)
- Accelerator pedal position sensor 2
- Refrigerant pressure sensor
Sensor power supply 3
- EVAP control system pressure sensor
DTC DETECTION LOGIC
| DTC | CONSULT screen terms (Trouble diagnosis content) | DTC detection condition | |
| P0643-00 | SENSOR POWER/CIRC (Sensor power supply 1 circuit short) | Diagnosis condition | Engine running at idle |
| Signal (terminal) | Sensor power supply 1 signal | ||
| Threshold | A voltage of power source for sensor is excessively low or high | ||
| Diagnosis delay time | - | ||
POSSIBLE CAUSE
Sensor power supply 1 circuit
FAIL-SAFE
Engine Control System
| Fail safe mode | Vehicle behavior |
|---|---|
| Device fix mode |
|
| Others | ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring. |
Idle Start/Stop System
When a DTC is detected, the start/stop indicator lamp blinks slowly and the idle start/stop system operation is prohibited. When ECM detects error while operating the idle start/stop system, ECM restarts the engine.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.