Dtc P0234 Turbocharger / Supercharger Overboost Condition

Engine. Lexus Is250, Is220D. Gse20 Ale20
2Ad-Fhv Engine Control System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0234, P0299 AND/OR P1251)

CHECK CONNECTION OF VACUUM HOSES

CHECK VACUUM (TURBOCHARGER - E-VRV FOR TURBOCHARGER CONTROL)

CHECK TERMINAL VOLTAGE (E-VRV POWER SOURCE)

CHECK E-VRV FOR TURBOCHARGER CONTROL (E-VRV OPERATION)

CHECK E-VRV FOR TURBOCHARGER CONTROL (E-VRV RESISTANCE)

CHECK HARNESS AND CONNECTOR (E-VRV FOR TURBOCHARGER CONTROL - ECM)

INSPECT TURBOCHARGER SUB-ASSEMBLY

INSPECT EGR VALVE ASSEMBLY

CHECK MANIFOLD ABSOLUTE PRESSURE SENSOR

DTC P0234 Turbocharger / Supercharger Overboost Condition

DTC P0299 Turbocharger / Supercharger Underboost

DTC P1251 Turbocharger / Supercharger Overboost Condition (Too High)


DESCRIPTION


DTC No.
DTC Detection Condition
Trouble Area
P0234
Turbochaging pressure is higher than the threshold for 60 seconds.
(1 trip detection logic)
  1. E-VRV for turbocharger control
  2. Open or short in VRV circuit
  3. Turbocharger
  4. Vacuum hose
  5. EGR valve
  6. ECM
P0299
Turbochaging pressure is lower than the threshold for 40 seconds when the turbochaging pressure deviates from the requirement.
(2 trip detection logic)
P1251
Turbochaging pressure is higher than the requirement for 0.5 seconds.
(1 trip detection logic)

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P0234 Turbocharger / Supercharger Overboost Condition


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).
1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0234, P0299 AND/OR P1251)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch ON (IG) and turn the intelligent tester ON.

  1. Enter the following menus: "Powertrain / Engine / DTC".

  1. Read DTCs.

    Result:

    Display (DTC output)
    		Proceed to
    P0234, P0299 and/or P1251
    		A
    P0234, P0299 and/or P1251 and other DTCs
    		B


B
GO TO DTC CHART
A


2.CHECK CONNECTION OF VACUUM HOSES
HINT:
Check the vacuum hoses of turbocharger system connections.


NG
REPAIR OR REPLACE VACUUM HOSES
OK


3.CHECK VACUUM (TURBOCHARGER - E-VRV FOR TURBOCHARGER CONTROL)

  1. Using a three-way connector, connect a vacuum gauge to the hose between the E-VRV and turbocharger.

  1. Warm up the engine coolant temperature to above 75°C (167°F).

  1. Check the vacuum at the engine speed of 900 rpm.

    Result:

    Vacuum
    		Proceed to
    0 kPa (0 mmHg, 0 in.Hg) to 50 kPa (375 mmHg, 14.8 in.Hg)
    		A
    Above 50 kPa (375 mmHg, 14.8 in.Hg)
    		B


B
Go to step 8
A


4.CHECK TERMINAL VOLTAGE (E-VRV POWER SOURCE)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P0234 Turbocharger / Supercharger Overboost Condition

  1. Disconnect the E79 E-VRV connector.

  1. Measure the voltage.

    Standard voltage:
    Tester Connection
    		Specified Condition
    VRV (E79-1) - Body ground
    		9 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5.CHECK E-VRV FOR TURBOCHARGER CONTROL (E-VRV OPERATION)

  1. Check the E-VRV operation (Click here).



NG
REPLACE E-VRV FOR TURBOCHARGER CONTROL
OK


6.CHECK E-VRV FOR TURBOCHARGER CONTROL (E-VRV RESISTANCE)

  1. Measure the E-VRV resistance (Click here).

    Standard resistance:
    11.1 to 12.5 Ω


NG
REPLACE E-VRV FOR TURBOCHARGER CONTROL
OK


7.CHECK HARNESS AND CONNECTOR (E-VRV FOR TURBOCHARGER CONTROL - ECM)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P0234 Turbocharger / Supercharger Overboost Condition

  1. Disconnect the E79 E-VRV connector.

  1. Disconnect the E59 ECM connector.

  1. Check the resistance between the wire harness side connectors.

    Standard resistance (Check for open):
    Tester Connection
    		Specified Condition
    VN (E59-84) - VRV (E79-2)
    		Below 1 Ω
    Standard resistance (Check for short):
    Tester Connection
    		Specified Condition
    VN (E59-84) or VRV (E79-2) - Body ground
    		10 kΩ or higher

  1. Reconnect the E-VRV connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


8.INSPECT TURBOCHARGER SUB-ASSEMBLY

  1. Check the turbocharging pressure (Click here).

    Standard:
    48 to 53 kPa (0.49 to 0.54 kgf/cm2, 6.9 to 7.7 psi)


NG
REPLACE TURBOCHARGER SUB-ASSEMBLY
OK


9.INSPECT EGR VALVE ASSEMBLY


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System. Dtc P0234 Turbocharger / Supercharger Overboost Condition

  1. Disconnect the E64 EGR valve connector.

  1. Measure the resistance between the terminals of the EGR valve.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 5
    		20°C (68°F)
    		6.5 to 7.5 Ω

  1. Reconnect the EGR valve connector.



NG
REPLACE EGR VALVE ASSEMBLY
OK


10.CHECK MANIFOLD ABSOLUTE PRESSURE SENSOR

  1. Connect an intelligent tester to the DLC3.

  1. Turn the engine switch ON (IG) and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Map and Atmosphere Pressure.

  1. Read the value displayed on the tester.

    OK:
    MAP:
    Same as atmospheric pressure.
    HINT:
    1 bar of atmospheric pressure is 101 kPa.

  1. Apply a negative pressure of 40 kPa (300 mmHg, 11.8 in.Hg) to the manifold absolute pressure sensor.

    OK:
    MAP:
    MAP decreases 40 kPa from atmospheric pressure.

  1. Apply a positive pressure of 69 kPa (518 mmHg, 20.4 in.Hg) to the manifold absolute pressure sensor.

    OK:
    MAP:
    MAP increases 69 kPa from atmospheric pressure.
HINT:
Even if the value output from the manifold absolute sensor is within the standard level, there may be a problem with the sensor due to deterioration because of age.


NG
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
OK

REPLACE ECM