DTC P050B-00: Cold Start Ignition Timing Performance [08/2023 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus RX 450h+, 2025 Lexus RX 350h, 2024 Lexus RX 450h+, 2024 Lexus RX 350h, and 2023 Lexus RX 350h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050B-00)

Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Result	Proceed to
P050B-00 and other DTCs are output	A
P050B-00 is output	B

HINT:

If any DTCs other than P050B-00 are output, troubleshoot those DTCs first.

Result:

GO TO DTC CHART. Refer to DIAGNOSTIC TROUBLE CODE CHART [08/2023 - 10/2024] , or Refer to DIAGNOSTIC TROUBLE CODE CHART [10/2024 - ]

Result:

See step 2

READ VALUE USING GTS (FUEL TRIM)

HINT:

Calculate the total fuel trim values to check the characteristic deviation of the mass air flow meter sub-assembly.

Pre-procedure1

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine.

Read the values displayed on the GTS at engine idle.

Powertrain > Engine > Data List

Tester Display
Short FT B1S1
Long FT B1S1

Add the Short FT B1S1 and Long FT B1S1 values to obtain the total fuel trim.

Result

Result	Proceed to
The sum of the value of Short FT B1S1 and Long FT B1S1 is -20 % or more, and less than 20 %	A
None of the above conditions are met	B

Post-procedure1

None.

Result:

See step 7

Result:

See step 3

INSPECT THROTTLE BODY WITH MOTOR ASSEMBLY (VISUALLY CHECK THROTTLE VALVE)

Check for foreign matter between the throttle valve and housing. If necessary, clean the throttle body with motor assembly. Also, check that the throttle valve moves smoothly.

Throttle valve is not contaminated with foreign matter and moves smoothly.

Result

Proceed to
OK
NG

Result:

See step 6

Result:

See step 4

PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

Pre-procedure1

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

HINT:

The A/C switch and all accessories should be off.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Intake Manifold Absolute Pressure
Engine Independent

NOTE:

Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.

The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard

-	Control the EGR Step Position (Active Test)
-	0 Steps	0 to 30 Steps
Intake Manifold Absolute Pressure (Data List)	(EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

HINT:

If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 15

Result:

See step 5

INSPECT EGR VALVE ASSEMBLY

Pre-procedure1

Remove the EGR valve assembly.
HINT:

Refer to REMOVAL [08/2023 - ]

Check if the EGR valve is stuck open.

EGR valve is tightly closed.

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 15

Result:

See step 27

REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY
HINT:

Refer to REMOVAL [08/2023 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 32

CHECK PCV VALVE AND HOSE CONNECTIONS

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Check the PCV hose connections.

Check the PCV valve.

Refer to INSPECTION [10/2022 - ]

PCV hose and PCV valve are connected correctly and are not damaged.

Result

Proceed to
OK
NG

Result:

See step 31

Result:

See step 8

CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks.

Refer to ON-VEHICLE INSPECTION [10/2022 - ]

No leaks from intake system.

Result

Proceed to
OK
NG

Result:

See step 30

Result:

See step 9

CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

Visually check that the air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

The air cleaner filter element sub-assembly is not excessively contaminated with dirt or oil.

Result

Proceed to
OK
NG

Result:

See step 29

Result:

See step 10

PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

Pre-procedure1

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is 75°C (167°F) or higher.

HINT:

The A/C switch and all accessories should be off.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Confirm that the value of Data List item Engine Independent is "Operate" then check the value of Intake Manifold Absolute Pressure while performing the Active Test.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Intake Manifold Absolute Pressure
Engine Independent

NOTE:

Make sure that the value of Data List item Engine Independent is "Operate" while performing the Active Test.
Do not leave the EGR valve open for 10 seconds or more during the Active Test.
Be sure to return the EGR valve to step 0 when the Active Test is completed.
Do not open the EGR valve 30 steps or more during the Active Test.

The value of Intake Manifold Absolute Pressure changes in response to the EGR step position when the value of Engine Independent is "Operate".

Standard

-	Control the EGR Step Position (Active Test)
-	0 Steps	0 to 30 Steps
Intake Manifold Absolute Pressure (Data List)	(EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

HINT:

If the value of Data List item Engine Independent is "Not Opr" when the engine is idling, charge control is being performed. Perform the Active Test after charge control is complete ("Operate" is displayed).
While performing the Active Test, if the increase in the value of Intake Manifold Absolute Pressure is small, the EGR valve assembly may be malfunctioning.
Even if the EGR valve assembly is malfunctioning, rough idling or an increase in the value of Intake Manifold Absolute Pressure may occur while performing the Active Test. However, the amount that the value of Intake Manifold Absolute Pressure increases will be smaller than normal.

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 12

Result:

See step 11

INSPECT EGR VALVE ASSEMBLY

Pre-procedure1

Remove the EGR valve assembly.
HINT:

Refer to REMOVAL [08/2023 - ]

Check if the EGR valve is stuck open.

EGR valve is tightly closed.

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 27

Result:

See step 12

PERFORM ACTIVE TEST USING GTS (CHECK VVT-IE SYSTEM FOR INTAKE CAMSHAFT)

Pre-procedure1

Remove the EFI NO. 1 fuse from the No. 1 engine room relay block and No. 1 junction block assembly and wait for at least 60 seconds.
HINT:

Clear the DTC without using the GTS.
Reinstall the EFI NO. 1 fuse.

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

HINT:

The A/C switch and all accessories should be off.

Read the Data List while performing the Active Test with the engine idling.

Powertrain > Engine > Active Test

Active Test Display
Control the VVT-iE Opening Angle Bank 1

Data List Display
Intake VVT Change Angle Bank 1
Intake VVT Target Angle Bank 1

Standard

Active Test Movement Order	Difference between "Intake VVT Change Angle Bank 1" and "Intake VVT Target Angle Bank 1"
0 deg → 10 deg → 20 deg → 40 deg → 0 deg → 10 deg → END	Within 4 DegFR

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

See step 24

Result:

See step 13

PERFORM ACTIVE TEST USING GTS (CONTROL THE EXHAUST VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 2

Result

Proceed to

OK

NG

Result:

NG

See step 17

Result:

OK

See step 14

READ VALUE USING GTS (MASS AIR FLOW SENSOR)

Pre-procedure1

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine.

Allow the engine to idle until Coolant Temperature is 75°C (167°F) or higher.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Read Mass Air Flow Sensor while maintaining an engine speed of 2500 rpm.

Powertrain > Engine > Data List

Tester Display
Engine Speed
Mass Air Flow Sensor

Standard

GTS Display	Condition	Specified Condition
Mass Air Flow Sensor	Engine warmed up Shift position: P A/C: Off Engine Speed: 2500 rpm	Between 6.2 and 18.6 gm/sec

Result

Result	Proceed to
The value of Mass Air Flow Sensor is between 6.2 and 18.6 gm/sec	A
None of the above conditions are met	B

Post-procedure1

None.

Result:

See step 34

Result:

See step 15

CLEAR DTC

Pre-procedure1

None.

Clear the DTCs.

Powertrain > Engine > Clear DTCs

Result

Proceed to
NEXT

Post-procedure1

Turn the ignition switch off and wait for at least 30 seconds.

Result:

See step 16

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

Pre-procedure1

NOTE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Check the DTC judgment result.

Powertrain > Engine > Utility

Tester Display
All Readiness

Input the DTC: P050B-00.

Result

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050B-00 is output)	B

Post-procedure1

None.

Result:

CHECK FOR INTERMITTENT PROBLEMS. Refer to CHECK FOR INTERMITTENT PROBLEMS [10/2022 - ]

Result:

See step 34

INSPECT CAM TIMING OIL CONTROL SOLENOID ASSEMBLY
Refer to INSPECTION [10/2022 - ]

Result

Proceed to

OK

NG

Result:

NG

See step 22

Result:

OK

See step 18
INSPECT CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY (EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY)
Refer to ON-VEHICLE INSPECTION [10/2022 - ]

Result

Proceed to

OK

NG

Result:

NG

See step 25

Result:

OK

See step 19
CHECK VALVE TIMING (CHECK FOR LOOSE AND JUMPED TEETH ON TIMING CHAIN)
Refer to PROCEDURE - Step 7

Result

Proceed to

OK

NG

Result:

OK

See step 28

Result:

NG

See step 20

CHECK ENGINE MECHANICAL SYSTEM

Check for mechanical malfunctions that affect the valve timing, such as a jumped tooth or stretching of the timing chain.

Result

Proceed to
OK
NG

Result:

See step 32

Result:

See step 21

REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA
HINT:

Perform "Inspection After Repair" after repairing or replacing the engine mechanical system.

Refer to INITIALIZATION [10/2022 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 32
REPLACE CAM TIMING OIL CONTROL SOLENOID ASSEMBLY
HINT:

Refer to REMOVAL [08/2023 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 23
INSPECT CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY (EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY)
Refer to ON-VEHICLE INSPECTION [10/2022 - ]

Result

Proceed to

OK

NG

Result:

OK

See step 26

Result:

NG

See step 25
REPLACE CAMSHAFT TIMING GEAR ASSEMBLY
HINT:

Refer to PROCEDURE - Step 43

Result

Proceed to

NEXT

Result:

NEXT

See step 32
REPLACE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY (EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY)
HINT:

Refer to REMOVAL [08/2023 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 26
PERFORM ACTIVE TEST USING GTS (CONTROL THE EXHAUST VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 2

Result

Proceed to

OK

NG

Result:

OK

See step 32

Result:

NG

See step 28
REPLACE EGR VALVE ASSEMBLY
HINT:

Refer to REMOVAL [08/2023 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 32
REPLACE CAMSHAFT TIMING EXHAUST GEAR ASSEMBLY
HINT:

Refer to PROCEDURE - Step 43

Result

Proceed to

NEXT

Result:

NEXT

See step 32

REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

Replace the air cleaner filter element sub-assembly.

Result

Proceed to
NEXT

Result:

See step 32

REPAIR OR REPLACE INTAKE SYSTEM

Repair or replace the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system.

Refer to INITIALIZATION [10/2022 - ]

Result

Proceed to
NEXT

Result:

See step 32

REPAIR OR REPLACE PCV VALVE OR HOSE

Repair or replace PCV valve or hose.

Result

Proceed to
NEXT

Result:

See step 32

CLEAR DTC

Pre-procedure1

None.

Clear the DTCs.

Powertrain > Engine > Clear DTCs

Result

Proceed to
NEXT

Post-procedure1

Turn the ignition switch off and wait for at least 30 seconds.

Result:

See step 33

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

Pre-procedure1

NOTE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Check the DTC judgment result.

Powertrain > Engine > Utility

Tester Display
All Readiness

Input the DTC: P050B-00.

Result

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050B-00 is output)	B

Post-procedure1

None.

Result:

END

Result:

See step 34

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)

Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter sub-assembly and ECM.

HINT:

Refer to ELECTRONIC CIRCUIT INSPECTION PROCEDURE [10/2022 - ]
Repair any problems.

Result

Proceed to
NEXT

Result:

See step 35

CLEAR DTC

Pre-procedure1

None.

Clear the DTCs.

Powertrain > Engine > Clear DTCs

Result

Proceed to
NEXT

Post-procedure1

Turn the ignition switch off and wait for at least 30 seconds.

Result:

See step 36

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

Pre-procedure1

NOTE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Check the DTC judgment result.

Powertrain > Engine > Utility

Tester Display
All Readiness

Input the DTC: P050B-00.

Result

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050B-00 is output)	B

Post-procedure1

None.

Result:

END

Result:

See step 37

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

Pre-procedure1

Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance

Tester Connection	Condition	Specified Condition	Result
B14-3 (VCC) - B28-78 (VCVG)	Always	Below 1 Ω	Ω
B14-1 (FG) - B28-101 (VG)	Always	Below 1 Ω	Ω
B14-2 (E2G) - B28-79 (E2G)	Always	Below 1 Ω	Ω
B14-3 (VCC) or B28-78 (VCVG) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
B14-1 (FG) or B28-101 (VG) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
B14-2 (E2G) or B28-79 (E2G) - Body ground and other terminals	Always	10 kΩ or higher	kΩ

Result

Proceed to
OK
NG

Post-procedure1

None.

Result:

REPAIR OR REPLACE HARNESS OR CONNECTOR

Result:

See step 38

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
HINT:
- Refer to REMOVAL [10/2022 - ]
- If the result of the inspection performed in step 14 (READ VALUE USING GTS (MASS AIR FLOW SENSOR)) indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
Result

Proceed to

NEXT

Result:

NEXT

See step 39

CLEAR DTC

Pre-procedure1

None.

Clear the DTCs.

Powertrain > Engine > Clear DTCs

Result

Proceed to
NEXT

Post-procedure1

Turn the ignition switch off and wait for at least 30 seconds.

Result:

See step 40

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

Pre-procedure1

NOTE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

Check that the engine coolant temperature is between -10 and 50°C (14 and 122°F).

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

Put the engine in Inspection Mode (Maintenance Mode).

Powertrain > Hybrid Control > Utility

Tester Display
Inspection Mode

Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.
Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

Check the DTC judgment result.

Powertrain > Engine > Utility

Tester Display
All Readiness

Input the DTC: P050B-00.

Result

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050B-00 is output)	B

Post-procedure1

None.

Result:

END

Result:

REPLACE ECM. Refer to REMOVAL [08/2023 - ]