4.
Select "ACTUATION TEST" parameter on the scantool.
specification : Fuel pump(fuel pump relay) operates at actuation test
Vain pump type fuel pump which is driven by electric motor is applied to this vehicle. Fuel pump which is installed inside of fuel tank supplies fuel to high pressure pump. ECM controls Fuel pump relay to supply power to low pressure fuel pump. The relay operates for 1.5 sec. for the diagnosis fuel pump relay at IG KEY ON, then if engine speed above 45rpm is detected by CKPS, relay turns ON and fuel is supplied to high pressure pump.
P0231 is set when no current or excessively low current is detected in fuel pump relay control circuit for more than 1 sec. at Fuel pump relay ON condition. This code is due to open or short to ground in glow relay control circuit or internal open in Fuel pump relay component.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● Fuel pump relay control circuit ● Fuel pump relay component | ||
Enable Conditions | ● IG KEY "ON" (monitoring only performed within relay operating condition) | |||
Threshold Value | ● Short to GND, Wiring open | |||
Diagnostic Time | ● 1.0 sec. | |||
Fail Safe | Fuel cut | NO | ||
EGR Off | NO | |||
Fuel Limit | NO | |||
Check Lamp | NO | |||
Relay Coil Resistance | Motor Type | Pumping Pressure |
75±10Ω(20℃) | Electric motor type vein pump | 4 - 5 bar |
Connect scantool to Data Link Cable (DLC).
Warm engine up to normal operating temperature.
Turn "OFF" electrical devices and A/C.
Select "ACTUATION TEST" parameter on the scantool.
specification : Fuel pump(fuel pump relay) operates at actuation test
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 Fuel pump motor power(Input) voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay.
Measure the voltage of fuel pump relay connector terminal 30.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
▶ Go to "2. Check Fuel pump motor power(Input) voltage" as follows.
▶ Repair open in E/R JUNCTION BOX 20A F/PUMP fuse and related circuit and go to "Verification of Vehicle Repair".
Check Relay coil power circuit voltage
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay.
IG KEY "ON".
Measure the voltage of fuel pump relay connector terminal 85.
Specification : 11.5V~13.0V
Is the measured voltage within the specification?
▶ Go to "Control Circuit Inspection".
▶ Repair E/R JUNCTION BOX 15A SNSR2 fuse and related circuit and go to "Verification of Vehicle Repair".
Check short to ground in control circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay.
IG KEY "ON".
Measure the voltage of fuel pump relay connector terminal 86.
Specification : 3.2V~3.7V
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ When no value is detected : Go to "2. Check open in control circuit".
▶ When high voltage is detected : Repair short to battery in signal circuit and go to "Verification of Vehicle Repair".
Check open in control circuit
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay and ECM connector.
Check continuity between fuel pump relay connector terminal 86 and ECM connector(C244-A) terminal 45.
specification : Continuity ( below 1.0Ω )
Is the measured resistance within the specification?
▶ Repair short to ground and go to "Verification of Vehicle Repair".
▶ Repair open in control circuit and go to "Verification of Vehicle Repair".
Check fuel pump relay component coil resistance
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay.
Measure the resistance of fuel pump relay component coil.
Specification : 75±5 Ω (20℃)
Is the measured resistance within the specification?
▶ Go to "2. Check fuel pump relay component operation" as follows.
▶ Replace fuel pump relay and go to "Verification of Vehicle Repair".
Check fuel pump relay component operation
IG KEY "OFF", ENGINE "OFF".
Disconnect fuel pump relay.
Supplies random B+ and ground to coil sides of fuel pump relay ( terminal 85, terminal 86).
Check continuity between fuel pump relay terminal 30 and terminal 87.
specification : When power is supplied : Continuity ( below 1.0Ω )
When power is not supplied : Discontinuity ( Infinite Ω )
Is the measured resistance within the specification?
▶ Go to "Verification of Vehicle Repair".
▶ Replace fuel pump relay and go to "Verification of Vehicle Repair".
※ Repeat this process 2~3 times.
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
