P0643

P0643 SENSOR POWER SUPPLY

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

- Accelerator pedal position (APP) sensor 1
- Camshaft position (CMP) sensor (PHASE)
- Electric throttle control actuator
- Battery current sensor
NOTE:
If sensor power supply 1 circuit is malfunctioning, DTC P0643 is displayed.

Sensor power supply 2

- Accelerator pedal position (APP) sensor 2
- Crankshaft position (CKP) sensor (POS)
- Refrigerant pressure sensor
- EVAP control system pressure sensor
- Engine oil pressure sensor


DTC Logic


DTC DETECTION LOGIC







DTC CONFIRMATION PROCEDURE


1. PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1.Turn ignition switch OFF and wait at least 10 seconds.
2.Turn ignition switch ON.
3.Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:


Before performing the following procedure, confirm that battery voltage is more than 8 V at idle.
- GO TO 2.

2. PERFORM DTC CONFIRMATION PROCEDURE

1.Start the engine and let it idle for 1 second.
2.Check DTC.
Is DTC detected?
YES- Proceed to "Diagnosis Procedure" .
NO- INSPECTION END


Diagnosis Procedure


1. CHECK SENSOR POWER SUPPLY 1

1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
Revision: March 20122013 Infiniti JX
3.Turn ignition switch ON.
4.Check the voltage between ECM harness connector and ground.





Is the inspection result normal?
YES- Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
NO- GO TO 2.

2. CHECK SENSOR POWER SUPPLY 1 ROUTING CIRCUIT FOR SHORT

1.Turn ignition switch OFF.
2.Disconnect following sensor harness connector.
3.Check harness for short to power and to ground, between the following terminals.





Is the inspection result normal?
YES- GO TO 3.
NO- Repair or replace error-detected parts.

3. CHECK COMPONENTS

Check the following.
- Throttle position sensor (Refer to "Component Inspection" P0122.)
- Battery current sensor (Refer to "Component Inspection" P1550.)
- Camshaft position sensor (PHASE) (bank 1) (Refer to "Component Inspection" P0340.)
- Camshaft position sensor (PHASE) (bank 2) (Refer to "Component Inspection" P0340.)
- Accelerator pedal position sensor (Refer to "Component Inspection" P2122.)
Is the inspection result normal?
YES- Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
NO- Replace malfunctioning component.
Revision: March 20122013 Infiniti JX