3.
Is the problem found?
 | ▶ Repair the trouble causing part and go to "Verification of Vehicle Repair". |
 | ▶ Go to "Power Circuit Inspection". |
ECM is activated by power supply. Signals from several sensors, such as CKPS and APS, is inputted to ECM. Comparing inputted siganals with control LOGIC saved at micro controller and EEPROM, ECM controlls engine as actuating injectors, solenoids and relays.
To guarantee accurate control, ECM performs SELF TEST, DIAGNOSIS of several sensors and actuators. And if serious trouble which affects vehicle performance occurrs, ECM sets DTCs.
At certain cases, ECM shuts down whole systems in order to prevent dangerous situation due to incorrect control.
P0643 is set when the voltage in 'Power #1' circuit is above upper limit for more than 0.1 sec.. This code is due to the short to battery in sensor power circuit or the voltage problem inside of ECM.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● APS 2 power supply circuit ● APT power supply circuit ● DPS power supply circuit ● VSA power supply circuit ● ECM component | ||
Enable Conditions | ● IG KEY "ON" | |||
Threshold Value | ● when the voltage is above the maximum voltage of sensor power supply. | |||
Diagnostic Time | ● 100ms | |||
Fail Safe | Fuel Cut | NO | ||
EGR Off | NO | |||
Fuel Limit | YES | |||
MIL | NO | |||
Sensor power 1 | Sensor power 2 | Sensor power 3 |
APS 2 | ACV | RPS |
APT | BPS | |
DPS | CAM | |
VSA | APS 1 | |
4830mV~5158mV | 4830mV~5158mV | 4830mV~5158mV |
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector for checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
| ▶ Repair the trouble causing part and go to "Verification of Vehicle Repair". |
| ▶ Go to "Power Circuit Inspection". |
Check power circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnector APS connector, A/C pressure transducer connector, Differntil pressure sensor connector and variable swirl control actuator connector.
IG KEY "ON".
Measure the voltage between power terminal of APS1 harness connector and chassis ground.
Measure the voltage between power terminal of A/C Pressure Transducer harness connector and chassis ground.
Measure the voltage between power terminal of Variable Swirl Ccontrol Actuator harness connector and chassis ground.
Measure the voltage between power terminal of Differentil Pressure Sensor harness connector and chassis ground.
Specification : 4.8V~5.1V
Is the measured voltage within the specification?
| ▶ Go to "Component Inspection". |
| ▶ Go to "2. Check short to ground in power circuit" as follows. |
Check short to ground in power circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect APS connector, A/C pressure transducer connector, Differntil pressure sensor connector, variable swirl control actuator connector, ECM connectors.
Check continuity between APS connector , A/C pressure transducer connector , Differntil pressure sensor connector or variable swirl control actuator connector and chassis ground.
specification : Discontinuity ( Infinite Ω )
Is the measured resistance within the specification?
| ▶ If the circuit is insulated well and the sensor power supply from ECM is low, replace ECM and go to "Verification of Vehicle Repair". |
| ▶ Repair short to ground and go to "Verification of Vehicle Repair". |
IG KEY "OFF", ENGINE "OFF".
Disconnect APS connector, A/C pressure transducer connector, Differntil pressure sensor connector and variable swirl control actuator connector.
Check that sensor connector power supply is within the specification after turning IG KEY "ON".
Connect APS connector, A/C pressure transducer connector, Differntil pressure sensor connector and variable swirl control actuator connector in turn.
Measure the voltage of power circuit of each sensor with all connector connected.
Specification : sensor power supply should not change as connecting APS connector, A/C pressure transducer connector, Differntil pressure sensor connector and variable swirl control actuator connector.
( If the change of sensor power supply occur as connecting sensor connector, this means the occurrence of short inside of sensor.)
Does change of sensor power supply occur as connecting sensor connector?
| ▶ Replace APS,A/C pressure transducer, Differntil pressure sensor or variable swirl control actuator. |
| ▶Go to "Verification of Vehicle Repair". |
After a repair, it is essential to verify that the fault is corrected.
After connecting GDS select "Diagnostic Trouble Codes(DTCs)" mode to and then clear DTC.
Drive the vehicle within DTC Enable conditions in General information.
After selecting "Diagnostic Trouble Codes(DTCs)" mode and check DTC is recorded again.
Are any DTCs recorded ?
| ▶ Go to the DTC guide of recorded NO. in GDS |
| ▶ System operates within specification. |
