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

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. 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

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 5

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 11

Result:

See step 4

REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY
HINT:

Refer to REMOVAL [10/2022 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 38

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 37

Result:

See step 6

CHECK INTAKE SYSTEM

Check the intake system for vacuum leaks.

Refer to PROCEDURE - Step 1

No leaks from intake system.

Result

Proceed to
OK
NG

Result:

See step 35

Result:

See step 7

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 32

Result:

See step 8

PERFORM ACTIVE TEST USING GTS (CONTROL THE INTAKE VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 14

Result

Proceed to

OK

NG

Result:

NG

See step 20

Result:

OK

See step 9
PERFORM ACTIVE TEST USING GTS (CONTROL THE EXHAUST VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 14

Result

Proceed to

OK

NG

Result:

NG

See step 13

Result:

OK

See step 10

READ VALUE USING GTS (MASS AIR FLOW SENSOR)

Pre-procedure1

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

According to the display on the GTS, read the Data List with the following condition.

Shift position: P
A/C: Off
Engine warmed up
Engine Speed: 3000 rpm

Powertrain > Engine > Data List

Tester Display
Engine Speed
Mass Air Flow Sensor

Result

Result	Proceed to
The value of MAF Sensor Bank1 is between 5 and 15 gm/sec	A
None of the above conditions are met	B

Post-procedure1

None.

Result:

See step 40

Result:

See step 11

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 12

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

NOTE:

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

Pre-procedure1

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

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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 40

INSPECT CAM TIMING OIL CONTROL SOLENOID ASSEMBLY (FOR EXHAUST SIDE)
Refer to PROCEDURE - Step 5

Result

Proceed to

OK

NG

Result:

NG

See step 16

Result:

OK

See step 14
INSPECT EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 12

Result

Proceed to

OK

NG

Result:

NG

See step 18

Result:

OK

See step 15
CHECK VALVE TIMING (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)
Refer to PROCEDURE - Step 7

Result

Proceed to

OK

NG

Result:

OK

See step 23

Result:

NG

See step 24
REPLACE CAM TIMING OIL CONTROL SOLENOID ASSEMBLY
Refer to PROCEDURE - Step 11

Result

Proceed to

NEXT

Result:

NEXT

See step 17
INSPECT EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 12

Result

Proceed to

OK

NG

Result:

OK

See step 19

Result:

NG

See step 18
REPLACE EXHAUST CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 13

Result

Proceed to

NEXT

Result:

NEXT

See step 19
PERFORM ACTIVE TEST USING GTS (CONTROL THE EXHAUST VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 14

Result

Proceed to

OK

NG

Result:

OK

See step 38

Result:

NG

See step 23
INSPECT CAM TIMING OIL CONTROL SOLENOID ASSEMBLY (FOR INTAKE SIDE)
Refer to PROCEDURE - Step 5

Result

Proceed to

OK

NG

Result:

NG

See step 30

Result:

OK

See step 21
INSPECT INTAKE CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 12

Result

Proceed to

OK

NG

Result:

NG

See step 33

Result:

OK

See step 22
CHECK VALVE TIMING (CHECK FOR LOOSE TIMING CHAIN AND JUMPED TEETH)
Refer to PROCEDURE - Step 7

Result

Proceed to

OK

NG

Result:

OK

See step 36

Result:

NG

See step 24
REPLACE CAMSHAFT TIMING EXHAUST GEAR ASSEMBLY
Refer to PROCEDURE - Step 15

Result

Proceed to

NEXT

Result:

NEXT

See step 38
CHECK ENGINE MECHANICAL SYSTEM
Refer to PROCEDURE - Step 8

Result

Proceed to

OK

NG

Result:

NG

See step 29

Result:

OK

See step 25

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 26

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

NOTE:

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

Pre-procedure1

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

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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: P050A-00.

Result

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050A-00 is output)	B

Post-procedure1

None.

Result:

See step 28

Result:

See step 27

CHECK FOR INTERMITTENT PROBLEMS
HINT:

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

Result

Proceed to

NEXT

Result:

NEXT

See step 38
REPLACE ECM
HINT:

Refer to REMOVAL [10/2022 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 38

REPAIR OR REPLACE MALFUNCTIONING PARTS, COMPONENT AND AREA

Repair or replace malfunctioning parts, component and area.

Result

Proceed to
NEXT

Result:

See step 38

REPLACE CAM TIMING OIL CONTROL SOLENOID ASSEMBLY (FOR INTAKE SIDE)
Refer to PROCEDURE - Step 11

Result

Proceed to

NEXT

Result:

NEXT

See step 31
INSPECT INTAKE CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 12

Result

Proceed to

OK

NG

Result:

OK

See step 34

Result:

NG

See step 33
REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY
HINT:

Refer to PROCEDURE - Step 2

Result

Proceed to

NEXT

Result:

NEXT

See step 38
REPLACE INTAKE CAMSHAFT TIMING GEAR BOLT ASSEMBLY
Refer to PROCEDURE - Step 13

Result

Proceed to

NEXT

Result:

NEXT

See step 34
PERFORM ACTIVE TEST USING GTS (CONTROL THE INTAKE VVT OCV DUTY RATIO BANK 1)
Refer to PROCEDURE - Step 14

Result

Proceed to

OK

NG

Result:

OK

See step 38

Result:

NG

See step 36
REPAIR OR REPLACE INTAKE SYSTEM
HINT:

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

Refer to INITIALIZATION [10/2022 - ]

Result

Proceed to

NEXT

Result:

NEXT

See step 38
REPLACE CAMSHAFT TIMING GEAR ASSEMBLY
Refer to PROCEDURE - Step 15

Result

Proceed to

NEXT

Result:

NEXT

See step 38

REPAIR OR REPLACE PCV VALVE OR HOSE

Repair or replace PCV valve or hose.

Result

Proceed to
NEXT

Result:

See step 38

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 39

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

NOTE:

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

Pre-procedure1

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

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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 40

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 41

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 42

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

NOTE:

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

Pre-procedure1

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

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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 43

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) - B27-73 (VCVG)	Always	Below 1 Ω	Ω
B14-1 (FG) - B27-75 (VG)	Always	Below 1 Ω	Ω
B14-2 (E2G) - B27-74 (E2G)	Always	Below 1 Ω	Ω
B14-3 (VCC) or B27-73 (VCVG) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
B14-1 (FG) or B27-75 (VG) - Body ground and other terminals	Always	10 kΩ or higher	kΩ
B14-2 (E2G) or B27-74 (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 44

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY
HINT:
- Refer to INSPECTION [10/2022 - ]
- If the result of the inspection performed in step 10 (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 45

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 46

CHECK WHETHER DTC OUTPUT RECURS (DTC P050B-00)

NOTE:

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

Pre-procedure1

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

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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 [10/2022 - ]