Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Cold Start Idle Control System Performance (P050A00)

Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual / Engine & Hybrid System / 2gr-fks (engine Control) / Sfi System / Cold Start Idle Control System Performance (P050A00)

MONITOR DESCRIPTION

This monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). The DTC will be stored after the engine idles for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started at an engine coolant temperature of less than 50°C (122°F), the ECM measures the accumulated mass air flow during engine idling. If the accumulated mass air flow does not reach the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and this DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.

NOTICE:

The idle speed control learned values are cleared by performing a learned value reset. Idle speed control learning needs to be performed before this DTC can be stored.

HINT:

Idle speed control learning is performed when the engine is warmed up and has been idling for 5 minutes.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

Note

P050A00

Cold Start Idle Control System Performance

Insufficient mass air flow after a cold start (2 trip detection logic).
  • Throttle body with motor assembly
  • Mass air flow meter sub-assembly
  • PCV system
  • Air cleaner filter element sub-assembly
  • Intake system
  • VVT system
  • Wire harness or connector
  • ECM

Comes on

DTC stored

SAE Code: P050A

MONITOR STRATEGY

Related DTCs

P050A: Cold start idle air speed control system

Required Sensors/Components (Main)

Throttle body with motor assembly

Required Sensors/Components (Related)

Mass air flow meter sub-assembly

Engine coolant temperature sensor

Frequency of Operation

Once per driving cycle

Duration

10 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored

P0010, P0020 (VVT oil control solenoid bank 1, 2)

P0011, P0021 (VVT system bank 1, 2 - advance)

P0012, P0022 (VVT system bank 1, 2 - retard)

P0013, P0023 (Exhaust VVT oil control solenoid bank 1, 2)

P0014, P0024 (Exhaust VVT system bank 1, 2 - advance)

P0015, P0025 (Exhaust VVT system bank 1, 2 - retard)

P0016, P0018 (VVT system bank 1, 2 - misalignment)

P0017, P0019 (Exhaust VVT system bank 1, 2 - misalignment)

P0087, P0088, P0191, P0192, P0193 (Fuel pressure sensor (for high pressure side))

P0101, P0102, P0103 (Mass air flow meter)

P0116, P0117, P0118 (Engine coolant temperature sensor)

P011B (Engine coolant temperature/intake air temperature sensor correlation)

P0121, P0122, P0123, P0222, P0223, P2135 (Throttle position sensor)

P0125 (Insufficient coolant temperature for closed loop fuel control)

P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D, P2195, P2196, P2197, P2198, P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2254, P2255, P2256 (Air fuel ratio sensor)

P0171, P0172, P0174, P0175 (Fuel system)

P0201, P0202, P0203, P0204, P0205, P0206, P062D, P21CF, P21D0, P21D1, P21D2, P21D3, P21D4 (Fuel injector)

P0300 - P0306 (Misfire)

P0335, P0337, P0338 (Crankshaft position sensor)

P0340, P0342, P0343, P0345, P0347, P0348 (VVT sensor)

P0365, P0367, P0368, P0390, P0392, P0393 (Exhaust VVT sensor)

P0500 (Vehicle speed sensor)

P0657, P2102, P2103, P2111, P2112, P2119 (Throttle actuator)

P0705 (Shift lever position switch)

P107B, P107C, P107D (Fuel pressure sensor (for low pressure side))

P11EA, P11EB, P11EC, P11ED, P11EE, P11EF, P11F0, P11F1, P219A, P219B, P219C, P219D, P219E, P219F, P21A0, P21A1 (Air-fuel ratio imbalance)

P1235 (High pressure fuel pump circuit)

Battery voltage

8 V or higher

Time after engine start

3 seconds or more

Starter

Off

Engine coolant temperature at engine start

-10°C (14°F) or higher

Engine coolant temperature

-10°C (14°F) or higher, and less than 50°C (122°F)

Engine idling time

3 seconds or more

Fuel-cut

Off

Vehicle speed

Less than 3 km/h (1.875 mph)

Time after shift position changed

1 second or more

Atmospheric pressure

76 kPa(abs) [11.02 psi(abs)] or higher

TYPICAL MALFUNCTION THRESHOLDS

Accumulated mass air flow

Less than 103.1 g (varies with engine coolant temperature, engine coolant temperature at engine start and ignition timing)

CONFIRMATION DRIVING PATTERN

HINT:

  • After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

    Click here

  • When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

    Click here

  1. Connect the Techstream to the DLC3.
  2. Turn the engine switch on (IG).
  3. Turn the Techstream on.
  4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
  5. Turn the engine switch off and wait for at least 30 seconds.
  6. Start the engine and warm it up for 5 minutes or more.
  7. Stop the engine.
  8. Leave the vehicle outside overnight.
  9. Turn the engine switch on (IG) [A].
  10. Turn the Techstream on.
  11. Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.
  12. Check that "Coolant Temperature" in the Data List is within the range of -10 to 50°C (14 to 122°F).
  13. Start the engine and warm it up until the coolant temperature is the same as the coolant temperature in the freeze frame data.
  14. Idle the engine for 1 minute or more [B].
  15. Enter the following menus: Powertrain / Engine / Trouble Codes [C].
  16. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  17. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
  18. Input the DTC: P050A00.
  19. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL
    • DTC judgment completed
    • System normal

    ABNORMAL
    • DTC judgment completed
    • System abnormal

    INCOMPLETE
    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system is malfunctioning.
    • If the judgment result is INCOMPLETE, idle the engine for 3 minutes, let the engine cool down, and then perform steps [A] through [B] again.
    • Idle the engine for 3 minutes, let the engine cool down, and then perform steps [A] through [C]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

Refer to DTC P010012.

Click here

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

1.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A00)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result

Proceed to

DTC P050A00 is output

A

DTC P050A00 and other DTCs are output

B

HINT:

If any DTCs other than P050A00 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

2.

READ VALUE USING TECHSTREAM (FUEL TRIM)

HINT:

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

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Short FT B1S1, Long FT B1S1, Short FT B2S1 and Long FT B2S1.

Powertrain > Engine > Data List

Tester Display

Short FT B1S1

Short FT B2S1

Long FT B1S1

Long FT B2S1

(e) Read the values displayed on the Techstream at engine idle.

(f) Add together the Short FT B1S1 and Long FT B1S1 values, and the Short FT B2S1 and Long FT B2S1 values to obtain the total fuel trim.

Standard:

Techstream Display

Specified Condition

Total of the Short FT B1S1 and Long FT B1S1

Between -20 and 20%

Total of the Short FT B2S1 and Long FT B2S1

Between -20 and 20%
NG

GO TO STEP 5

OK

3.

INSPECT THROTTLE BODY WITH MOTOR ASSEMBLY (THROTTLE VALVE)

(a) Check that there are no deposits around the throttle valve and throttle valve condition.

OK:

No deposits around the throttle valve and throttle valve moves smoothly.

OK

GO TO STEP 10

NG

4.

REPAIR OR REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY

(a) Repair or replace the throttle body with motor assembly.

Click here

HINT:

Perform "Inspection After Repair" after repairing or replacing the throttle body with motor assembly.

Click here

NEXT

GO TO STEP 15

5.

CHECK PCV SYSTEM

(a) Check the PCV hose connections.

Click here

OK:

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

NG

GO TO STEP 14

OK

6.

CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks.

Click here

OK:

No leaks from the intake system.

NG

GO TO STEP 13

OK

7.

CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

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

OK:

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

NG

GO TO STEP 12

OK

8.

PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE CAMSHAFT TIMING OIL CONTROL VALVE ASSEMBLY)

(a) Operate the VVT system through the Active Test, and check if the VVT system is operating normally.

(1) Perform the Active Test, referring to DTC P001100 Procedure (VVT system for intake camshaft).

Click here

(2) Perform the Active Test, referring to DTC P001400 Procedure (VVT system for exhaust camshaft).

Click here

NG

GO TO STEP 11

OK

9.

READ VALUE USING TECHSTREAM (MASS AIR FLOW SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Data List / Engine Speed, Mass Air Flow Sensor and Coolant Temperature.

Powertrain > Engine > Data List

Tester Display

Engine Speed

Mass Air Flow Sensor

Coolant Temperature

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

(f) Read Mass Air Flow Sensor while maintaining an engine speed of 3000 rpm.

Standard:

Techstream Display

Condition

Specified Condition

Mass Air Flow Sensor

Engine warmed up

Shift lever position: P

A/C: Off

Engine Speed: 3000 rpm

Between 10.6 gm/sec and 15.8 gm/sec
NG

GO TO STEP 16

OK

10.

CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(e) Turn the engine switch off and wait for at least 30 seconds.

(f) Turn the engine switch on (IG).

(g) Turn the Techstream on.

(h) Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.

Powertrain > Engine > Data List

Tester Display

Coolant Temperature

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

(j) 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.

(k) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(l) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

Powertrain > Engine > Utility

Tester Display

All Readiness

(m) Input the DTC: P050A00.

(n) Check the DTC judgment result.

Result

Proceed to

NORMAL

(DTCs are not output)

A

ABNORMAL

(DTC P050A00 is output)

B
A

CHECK FOR INTERMITTENT PROBLEMS

B

GO TO STEP 16

11.

CHECK AND REPAIR VVT SYSTEM

(a) Check and repair the VVT system.

HINT:

  • Refer to DTC P001100 Procedure for intake camshaft.

    Click here

  • Refer to DTC P001400 Procedure for exhaust camshaft.

    Click here

NEXT

GO TO STEP 15

12.

REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

(a) Replace the air cleaner filter element sub-assembly.

NEXT

GO TO STEP 15

13.

REPAIR OR REPLACE INTAKE SYSTEM

(a) Repair or replace the intake system.

HINT:

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

Click here

NEXT

GO TO STEP 15

14.

REPAIR OR REPLACE PCV HOSE

(a) Repair or replace the PCV valve or hose.

NEXT

15.

CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(e) Turn the engine switch off and wait for at least 30 seconds.

(f) Turn the engine switch on (IG).

(g) Turn the Techstream on.

(h) Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.

Powertrain > Engine > Data List

Tester Display

Coolant Temperature

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

(j) 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.

(k) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(l) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

Powertrain > Engine > Utility

Tester Display

All Readiness

(m) Input the DTC: P050A00.

(n) Check the DTC judgment result.

Result

Proceed to

NORMAL

(DTCs are not output)

A

ABNORMAL

(DTC P050A00 is output)

B
A

END
B

16.

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

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

Click here

HINT:

Repair any problems.

NEXT

17.

CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(e) Turn the engine switch off and wait for at least 30 seconds.

(f) Turn the engine switch on (IG).

(g) Turn the Techstream on.

(h) Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.

Powertrain > Engine > Data List

Tester Display

Coolant Temperature

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

(j) 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.

(k) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(l) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

Powertrain > Engine > Utility

Tester Display

All Readiness

(m) Input the DTC: P050A00.

(n) Check the DTC judgment result.

Result

Proceed to

NORMAL

(DTCs are not output)

A

ABNORMAL

(DTC P050A00 is output)

B
A

END
B

18.

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

(a) Disconnect the mass air flow meter sub-assembly connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

D9-3 (5V) - D2-90 (VC)

Always

Below 1 Ω

D9-1 (FG) - D2-116 (VG)

Always

Below 1 Ω

D9-2 (E2G) - D2-115 (E2G)

Always

Below 1 Ω

D9-3 (5V) or D2-90 (VC) - Body ground and other terminals

Always

10 kΩ or higher

D9-1 (FG) or D2-116 (VG) - Body ground and other terminals

Always

10 kΩ or higher

D9-2 (E2G) or D2-115 (E2G) - Body ground and other terminals

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

19.

REPLACE MASS AIR FLOW METER SUB-ASSEMBLY

(a) Replace the mass air flow meter sub-assembly.

Click here

HINT:

  • If the results of the inspections performed in step 9 indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
  • Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

    Click here

NEXT

20.

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

HINT:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the freeze frame data).

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs.

Powertrain > Engine > Clear DTCs

(e) Turn the engine switch off and wait for at least 30 seconds.

(f) Turn the engine switch on (IG).

(g) Turn the Techstream on.

(h) Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.

Powertrain > Engine > Data List

Tester Display

Coolant Temperature

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

(j) 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.

(k) Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.

(l) Enter the following menus: Powertrain / Engine / Utility / All Readiness.

Powertrain > Engine > Utility

Tester Display

All Readiness

(m) Input the DTC: P050A00.

(n) Check the DTC judgment result.

Result

Proceed to

NORMAL

(DTCs are not output)

A

ABNORMAL

(DTC P050A00 is output)

B
A

END
B

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