DTC Code | DTC Name |
---|---|
P1251 | Turbocharger / Supercharger Overboost Condition (Too High) |
DESCRIPTION
Refer to DTC P0046.
Click hereНажмите здесь
DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory |
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P1251 | Turbocharger / Supercharger Overboost Condition (Too High) | Boost pressure is higher than the threshold* for 5 seconds (1 trip detection logic). |
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Comes on | DTC stored |
*: This value changes based on engine speed, atmospheric pressure and the engine coolant temperature (when the vehicle is being driven in 2nd gear with the accelerator pedal fully depressed and the engine speed at 3000 rpm, the value is between approximately 200 and 232 kPa).
DTC No. | Data List |
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P1251 |
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If DTC P1251 is stored due to the VN turbo vane being stuck closed, the following symptoms may appear:
Vehicle surge when driving with full load
Sudden lack of power due to power being limited
CONFIRMATION DRIVING PATTERN
DTC No. | DTC Detection Drive Pattern |
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P1251 | Vehicle being driven |
CAUTION / NOTICE / HINT
After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click hereНажмите здесь).
After replacing an injector assembly, the ECM needs registration.
Click hereНажмите здесь
Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.
PROCEDURE
CHECK FOR ANY OTHER DTCS OUTPUT (RECORD STORED DTC AND FREEZE FRAME DATA)
Connect the GTS to the DLC3.
Turn the ignition switch to ON and turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the DTCs.
Powertrain > Engine and ECT > Trouble CodesRecord the stored DTCs and freeze frame data.
Be sure to carefully examine "MAP" and "Target Booster Pressure" in the freeze frame data.
Result | ||||||
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DC motor-related DTCs: P0046, P0047 and P0048.
Click hereНажмите здесь
Nozzle vane position sensor-related DTCs: P2564 and P2565.
Click hereНажмите здесь
B |
GO TO DTC CHART Click here Нажмите здесь |
A |
CHECK INTAKE SYSTEM
Check if the hoses between the air cleaner case sub-assembly and turbocharger sub-assembly, and turbocharger sub-assembly and intake manifold are damaged or disconnected.
Result | ||||||
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Be sure to check if the hoses and pipes between the air cleaner and compressor are disconnected as disconnection of a hose or pipe can cause overboost. Also, check the high pressure hoses for disconnection due to overboost.
Check for disconnection of the exhaust pipes.
Using your hand, check whether the pipes and hoses in the intake system are securely connected.
Check for any modifications in the intake system made by the user.
B | Нажмите здесь |
GO TO STEP 4 |
A |
REPAIR OR REPLACE INTAKE SYSTEM
Repair or replace the malfunctioning part in the intake system.
Result | ||
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NEXT |
CHECK TURBOCHARGER SUB-ASSEMBLY (DC MOTOR OPERATION)
Check the turbocharger sub-assembly.
Click hereНажмите здесь
Check the movement of the actuator rod when the ignition switch is turned from ON to off.
Result | |||
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NG | Нажмите здесь |
OK |
PERFORM ACTIVE TEST USING GTS (ACTIVATE THE EGR VALVE CLOSE)
Connect the GTS to the DLC3.
Start the engine and warm it up, and make sure the A/C switch and all accessory switches are off.
Turn the ignition switch off and wait for 30 seconds.
Start the engine and turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.
Powertrain > Engine and ECT > Data ListTester Display |
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MAF |
Read the MAF value displayed on the GTS while the engine is idling.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Activate the EGR Valve Close / All Data / MAF.
Powertrain > Engine and ECT > Active TestActive Test Display |
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Activate the EGR Valve Close |
Data List Display |
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MAF |
Read the MAF value when the EGR valve is closed using the Active Test function.
If idling continues for 20 minutes or more, the EGR valve target opening angle becomes 0% (EGR valve fully closed). As this makes diagnosis impossible, it becomes necessary to drive the vehicle or to restart the engine.
Before performing diagnosis, confirm that the EGR valve target opening angle is not 0%.
When "Coolant Temp" is 75°C (167°F) or higher during idle, the exhaust gas flows through the EGR pipe with cooler sub-assembly. If MAF does not change when the EGR is cut even though the EGR valve is operating normally, the EGR pipe with cooler sub-assembly may be clogged.
When idling while warming up the engine, the actuator operates and the EGR pipe with cooler sub-assembly is bypassed. However, if the connector of the No. 1 vacuum switching valve assembly (for EGR cooler) is disconnected, the EGR pipe with cooler sub-assembly is not bypassed and it is possible to check if the EGR pipe with cooler sub-assembly is clogged.
Result | ||||||||
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As the measured values may differ from those shown below due to factors such as differences in measuring environments and changes in vehicle condition due to aging, do not use these values to determine whether the vehicle is malfunctioning or not.
The problem may be a temporary, due to the entry of deposits or foreign matter. Check that there are no deposits or foreign matter in the electric EGR control valve assembly or mass air flow meter assembly.
Reference | ||||||||
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B | Нажмите здесь |
A |
READ VALUE USING GTS (TARGET EGR POSITION AND ACTUAL EGR VALVE POS.)
Check the change in the values of "Target EGR Position" and "Actual EGR Valve Pos." in the Data List from the time when the "Activate the EGR valve Close" Active Test was performed in the previous step.
Result | ||||||
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B | Нажмите здесь |
A |
CHECK FOR DEPOSIT (ELECTRIC EGR CONTROL VALVE ASSEMBLY)
Remove the electric EGR control valve assembly.
Click hereНажмите здесь
Visually check the electric EGR control valve assembly for deposits. If there are deposits, clean the electric EGR control valve assembly.
When cleaning the electric EGR control valve assembly, make sure the valve is completely closed.
When cleaning the electric EGR control valve assembly, perform initialization procedure.
Click hereНажмите здесь
Do not forcibly
When cleaning the electric EGR control valve assembly, use a piece of cloth soaked with cleaning solvent. Spraying solvent directly onto these parts or soaking the parts in solvent may damage the parts.
When cleaning the EGR control valve, care should be taken to prevent the ingress of cleaning solvent into the bearings of valve shaft, and when wiping off deposits on the EGR control valve, care should be taken not to push the deposits into the bearings of valve shaft. These contaminants may adversely affect on the function of EGR control valve.
If the EGR valve is stuck closed, the intake air amount increases and engine vibration may worsen.
If the EGR valve does not close properly or is stuck open, the amount of recirculated exhaust gas becomes excessive and combustion becomes unstable. Also, there may be a lack of power.
Result | ||
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NEXT | Нажмите здесь |
GO TO STEP 13 |
REPLACE EGR PIPE WITH COOLER SUB-ASSEMBLY
Replace the EGR pipe with cooler sub-assembly.
Click hereНажмите здесь
Result | ||
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NEXT | Нажмите здесь |
GO TO STEP 13 |
READ VALUE USING GTS (INJECTION VOLUME)
Connect the GTS to the DLC3.
Start the engine and warm it up until the engine coolant temperature reaches 70°C (158°F) or higher.
Allow the engine to idle for 1 minute or more.
The A/C switch and all accessory switches should be off with a fully warm engine.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Injection Volume.
Powertrain > Engine and ECT > Data ListTester Display |
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Injection Volume |
Check the value of Injection Volume at 4000 rpm without load.
Result | ||||||
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If the injector assembly is malfunctioning, the compensatory injection volume remains at 5.0 mm3/st.
If there is a disconnection, the feedback value will increase and +5.0 mm3/st will be indicated, because it will become impossible for the injector to inject.
B | Нажмите здесь |
GO TO STEP 13 |
A |
REPLACE INJECTOR ASSEMBLIES OF ALL CYLINDERS
Replace the injector assemblies.
Click here Нажмите здесь
When replacing the injector assembly for a cylinder, always be sure to use a new injection pipe.
Follow the procedure in the repair manual and temporarily install the injection pipes and nozzle leakage pipe, and then correctly position the injector assemblies. After that, tighten parts according to the torque specifications.
If the installation procedure is not performed correctly, injector assemblies may become out of position, which may cause the injector assemblies to deteriorate, resulting in malfunctions.
If an injector assembly deteriorates and malfunctions, other problems such as knocking, rough idle, etc. may occur.
If an injector assembly becomes out of position, it is possible that the seal between the injector assembly and injection pipe may become incomplete, resulting in a fuel leak.
Result | ||
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NEXT |
BLEED AIR FROM FUEL SYSTEM
Bleed the air from the fuel system.
Click hereНажмите здесь
Result | ||
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NEXT |
REGISTER INJECTOR COMPENSATION CODE AND PERFORM PILOT QUANTITY LEARNING
Register the injector compensation codes.
Click hereНажмите здесь
Perform the pilot quantity learning.
Click hereНажмите здесь
Result | ||
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NEXT |
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs.
Powertrain > Engine and ECT > Clear DTCsTurn the ignition switch off and wait for 30 seconds.
Start the engine and warm it up.
Turn the GTS on.
Confirm the value of Engine Speed from the Freeze Frame Data recorded previously, and then drive the vehicle according to the Engine Speed value.
ОСТОРОЖНО
When performing the confirmation driving pattern, obey all speed limits and traffic laws.
Take a snapshot of "MAP" and "Target Boost Pressure" in the Data List with the GTS while driving the vehicle.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the DTCs.
Powertrain > Engine and ECT > Trouble CodesResult | ||||||
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|
*: Return to "Check Intake System" and inspect areas that have not been inspected yet.
A |
END |
B | Нажмите здесь |
GO TO STEP 2 |
CHECK HARNESS AND CONNECTOR (TURBOCHARGER SUB-ASSEMBLY - ECM)
Disconnect the DC motor connector.
Disconnect the nozzle vane position sensor connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
Standard Resistance | ||||||||||||||||||||||||||||||
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Result | |||
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|
OK |
INSPECT TURBOCHARGER SUB-ASSEMBLY Click hereНажмите здесь |
NG |
REPLACE HARNESS OR CONNECTOR |