COMPONENT LOCATION
GENERAL DESCRIPTION

Fuel Pressure Regulator Valve(FPRV) is integrated with high pressure pump and controls common rail pressure as regulating the quantity of fuel which is delivered to common rail. In order to control rail pressure to be optimum to current driving condition, ECM controls fuel pressure regulator valve operating current(with the method of duty-control) using RPCV signal, RPM and APS signal.The lower Fuel pressure regulator valve current is, the more fuel is supplied to common rail.

DTC DESCRIPTION

P0252 is set when excessive current in control circuit of Fuel metering unit(integrated with high pressure pump) is detected for more than 0.28 sec.. This code is due to short to battery in control circuit or Fuel metering unit internal short.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible Cause

DTC Strategy

●

Voltage monitoring

●

FPRV circuit

●

FPRV component

Enable Conditions

●

IG KEY "ON"

Threshold Value

●

Short to battery (control circuit in FPRV)

Diagnostic Time

●

0.28 sec.

Fail Safe

Fuel cut

NO

EGR Off

NO

Fuel Limit

YES

Check Lamp

YES

SIGNAL CIRCUIT INSPECTION
SPECIFICATION

Rail pressure regulator valve resistance

Operating frequancy

2.9 ~ 3.15Ω (20℃)

185 Hz

SCHEMATIC DIAGRAM
MONITOR SCANTOOL DATA
1.

Connect Scantool to Data Link Connector (DLC).

2.

Warm engine up to normal operating temperature.

3.

Turn "OFF" electrical devices and A/C.

4.

Monitor "FUEL PRESSURE MEASURED", "INJ. PUMP REGULATOR","RAIL PRESS. REGULATOR1" parameter on the Scantool.

Specification :

Idle(without load)

Accelerating(stall test)

Diagnosis

FUEL PRESSURE MEASURED

27 ± 5 Mpa

above 75 Mpa

press. increases

INJ. PUMP REGULATOR

34 ± 3%

38 ± 3%

duty increases

RAIL PRESS. REGULATOR1

16 ± 3%

45 ± 3%

duty increases

note

The waveform of fuel pressure regulator valve installed at high pressure pump(fuel detecting MPROP) shows 35 ± 3% duty at idle, duty rises to approx. 38% at acceleration to raise rail pressure.

The waveform of rail pressure regulator valve installed at common rail shows 17 ± 3% duty at idle, duty rises to approx. 45% at acceleration to raise rail pressure.

TERMINAL AND CONNECTOR INSPECTION
1.

Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.

2.

Perform checking procedure as follows.

(1)

Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.

(2)

Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.

note

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. )

3.

Is the problem found?

▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".

▶ Go to "Power Circuit Inspection".

POWER CIRCUIT INSPECTION
1.

Check power circuit voltage

(1)

IG KEY "OFF", ENGINE "OFF"

(2)

Disconnect FPRV connector.

(3)

IG KEY "ON"

(4)

Measure the voltage of FPRV connector terminal 1.

specification : 11.5V~13.0V

(5)

Is the measured voltage within the specification?

▶ Go to "Control Circuit Inspection".

▶ Repair open between FPRV connector terminal 1 and ECM connector terminal 19 and go to "Verification of Vehicle Repair".

CONTROL CIRCUIT INSPECTION
1.

Check monitoring voltage in control circuit

(1)

IG KEY "OFF", ENGINE "OFF"

(2)

Disconnect FPRV connector.

(3)

IG KEY "ON"

(4)

Measure the voltage of FPRV connector terminal 2.

specification : 3.2V~3.7V

(5)

Is the measured voltage within the specification?

▶ Go to "Component Inspection"

▶ When voltage is not detected : Go to "2. Check open in control circuit" as follows.

▶ When high voltage is detected : Repair short to battery and go to "Verification of Vehicle Repair".

2.

Check open in control circuit

(1)

IG KEY "OFF", ENGINE "OFF"

(2)

Disconnect FPRV and ECM connector.

(3)

Check continuity between FPRV connector terminal 2 and ECM connector (C244-A) terminal 49.

specification : Continuity ( below 1.0Ω )

(4)

Is the measured resistance within the specification?

▶ Repair short to ground in FPRV control circuit and go to "Verification of Vehicle Repair".

▶ Repair open in FPRV control circuit and go to "Verification of Vehicle Repair".

COMPONENT INSPECTION
1.

Check FPRV component resistance

(1)

IG KEY "OFF", ENGINE "OFF".

(2)

Disconnect rail pressure regulator valve connector.

(3)

Check FPRV component resistance.

Specification : 2.9 ~ 3.15Ω (20℃)

(4)

Is FPRV component resistance within the specification?

▶ Go to "Verification of Vehicle Repair".

▶ Replace High pressure pump ass'y and go to "Verification of Vehicle Repair".

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verify that the fault is corrected.

1.

After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.

2.

Clear recorded DTC using Scantool.

3.

Drive the vehicle within DTC "Enable conditions" in "General information".

4.

After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.

5.

Are any DTCs recorded ?

▶ Go to the DTC guide of recorded NO. in Scantool.

▶ System operates within specification.

Яндекс.Метрика