DTC P0234 DTC P0299 DTC P1251

DTC P0234 Turbocharger / Supercharger Overboost Condition

DTC P0299 Turbocharger / Supercharger Underboost

DTC P1251 Turbocharger / Supercharger Overboost Condition (Too High)

Description

Toyota fault code list DTC P0234 DTC P0299 DTC P1251 2AD-FHV

DTC No. DTC Detection Condition Trouble Area
P0234
P0299
P1251
When the turbocharger pressure exceeds the standard value for 0.5 seconds or more
(1 trip detection logic)
  1. VRV for turbocharger control
  2. Open or short in VRV circuit
  3. Turbocharger
  4. Vacuum hose
  5. EGR valve
  6. ECM
Actual turbocharger pressure is deviated 20 kPa (150 mmHg, 5.9 in.Hg) or more from the simulated target pressure for 60 seconds
(1 trip detection logic)

Wiring diagram


Wiring diagram DTC P0234,DTC P0299,DTC P1251

Inspection procedure

 

NOTICE:

After replacing the ECM, the new ECM needs registration and initialization.

1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0234, P0299 AND/OR P1251)
  1. Connect the intelligent tester to the DLC3.

  2. Turn the ignition switch on (IG) and turn the tester ON.

  3. Enter the following menus: Powertrain / Engine and ECT / DTC.

  4. 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 HOSE

 

HINT:

Check the vacuum hoses of turbocharger system connections.

  NG  
REPAIR OR REPLACE VACUUM HOSE
 
OK  
   
3.CHECK VACUUM (TURBOCHARGER - VRV FOR TURBOCHARGER CONTROL)
  1. Using a three-way connector, connect a vacuum gauge to the hose between the VRV and turbocharger.

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

  3. 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 6
 
A  
   
4.INSPECT VRV FOR TURBOCHARGER CONTROL (VRV RESISTANCE)
  1. Measure the VRV resistance.

     

    Standard resistance:

    11.1 to 12.5 ?

 

  NG  
REPLACE VRV FOR TURBOCHARGER CONTROL
 
OK  
   
5.CHECK WIRE HARNESS (VRV FOR TURBOCHARGER CONTROL - ECM)
Check wire harness (vrv for turbocharger control - ecm)
  1. Disconnect the B44 VRV connector.

  2. Disconnect the B32 ECM connector.

  3. Measure the resistance of the wire harness side connectors.

     

    Standard resistance:

    Tester Connection Specified Condition
    B32-84 (VN) - B44-2 Below 1 ?
    B32-84 (VN) or B44-2 - Body ground 10 k? or higher
  4. Reconnect the VRV connector.

  5. Reconnect the ECM connector.

 

  NG  
REPAIR OR REPLACE HARNESS AND CONNECTOR
 
OK  
   
6.INSPECT TURBOCHARGER SUB-ASSEMBLY
  1. Check the turbocharger sub-assembly.

 

  NG  
REPLACE TURBOCHARGER SUB-ASSEMBLY
 
OK  
   
7.INSPECT EGR VALVE ASSEMBLY
  1. Check the EGR valve assembly.

 

  NG  
REPLACE EGR VALVE ASSEMBLY
 
OK  
   
8.READ VALUE OF MANIFOLD ABSOLUTE PRESSURE SENSOR
  1. Connect the intelligent tester to the DLC3.

  2. Turn the ignition switch on (IG) and turn the tester ON.

  3. Enter the following menus: Powertrain / Engine and ECT / Data List / MAP and Atmosphere Pressure.

  4. Read the value.

     

    OK:

    Condition MAP Value
    No pressure applied Same as atmospheric pressure
    Vacuum applied Becomes vacuum
    Pressure applied Becomes pressurized

 

  NG  
REPLACE MANIFOLD ABSOLUTE PRESSURE SENSOR
 
OK  
   
REPLACE ECM