Toyota Tundra Service Manual: Cold Start Idle Air Control System Performance (P050A)

Toyota Tundra Service Manual / Engine, Hybrid System / 1ur-fe Engine Control / Sfi System / Cold Start Idle Air Control System Performance (P050A)

DESCRIPTION

This monitor will run when the engine is started with the engine coolant temperature at -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 with the engine coolant temperature at lower than 50°C (122°F), the ECM measures the accumulated mass air flow at engine idling. If it does not reach the criteria within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The ETCS (Electronic Throttle Control System) controls the idle speed. The ETCS operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.

NOTICE:

When the cable is disconnected from the negative battery terminal during inspections or repairs, the ISC (Idle Speed Control) learning values are cleared. This DTC cannot be stored with the ISC learning values cleared.

The ISC learning is performed when the engine is warmed up and has been idling for 5 minutes.

DTC No.

DTC Detection Condition

Trouble Area

P050A

Insufficient mass air flow at cold start

(2 trip detection logic)
  • Throttle with motor body assembly
  • Mass air flow meter
  • PCV hose
  • Air cleaner filter element sub-assembly
  • Intake system
  • VVT system
  • EGR valve assembly
  • ECM
  • Wire harness or connector

MONITOR STRATEGY

Related DTCs

P050A: Cold start idle air speed control system

Required sensors/Components (Main)

Throttle with motor body assembly

Required sensors/Components (Related)

Mass air flow meter

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 following DTCs not present

P0010, P0020 (VVT oil control valve)

P0011, P0021 (VVT system - Advance)

P0012, P0022 (VVT system - Retard)

P0013, P0023 (Exhaust VVT oil control valve)

P0014, P0024 (Exhaust VVT system - Advance)

P0015, P0025 (Exhaust VVT system - Retard)

P0016, P0018 (VVT system - Misalignment)

P0017, P0019 (Exhaust VVT system - Misalignment)

P006A, P0107, P0108 (Manifold absolute pressure)

P0102, P0103 (Mass air flow meter)

P0115, P0117, P0118 (Engine coolant temperature sensor)

P0120, P0121, P0122, P0123, P0220, 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, P2255, P2256 (Air fuel ratio sensor)

P0171, P0172, P0174, P0175 (Fuel system)

P0301 - P0308 (Misfire)

P0335 (Crankshaft position sensor)

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

P1340 (Camshaft position sensor)

P0351 - P0358 (Igniter)

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

P0401 (EGR system)

P0500 (Vehicle speed sensor)

P219A, P219B, P219C, P219D, P219E, P219F, P21A0, P21A1, P21A2, P21A3 (Air-fuel ratio imbalance)

Battery voltage

8 V or more

Time after engine start

3 seconds or more

Starter

OFF

ECT at engine start

-10°C (14°F) or more

ECT

-10 to 50°C (14 to 122°F)

Engine idling

3 seconds or more

Fuel-cut

OFF

Vehicle speed

Less than 3 km/h (1.875 mph)

Time after shift position changed

2 seconds or more

Atmospheric pressure

76 kPa (570 mmHg) or more

TYPICAL MALFUNCTION THRESHOLDS

Accumulated mass air flow

Less than 106 g (varies with ECT)

CONFIRMATION DRIVING PATTERN

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

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  13. Input the DTC: P050A.
  14. Check the DTC judgment result.

    Tester 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

    N/A
    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    If the judgment result shows ABNORMAL, the system has a malfunction.

  15. If the judgment result shows INCOMPLETE or N/A, idle the engine for 3 minutes, let the engine cool down, and then perform steps [A] through [B] again.
  16. If no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

CAUTION / NOTICE / HINT

HINT:

Read freeze frame data using the Techstream. 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, 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

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

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

(e) Read the pending DTCs.

Result

Result

Proceed to

DTC P050A is output

A

DTC P050A and other DTCs are output

B

HINT:

If any DTCs other than P050A 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.

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Turn the Techstream on.

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

(e) Read the values displayed on the Techstream.

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

Total of Short FT B1S1 and Long FT B1S1, or Short FT B2S1 and Long FT B2S1 values is between -20% and 20%.

NG

GO TO STEP 7

OK

3.

INSPECT THROTTLE WITH MOTOR BODY ASSEMBLY (THROTTLE BODY)

(a) Check for deposits around the throttle valve and check the throttle valve condition.

OK:

No deposits around throttle valve and throttle valve moves smoothly.

NG

GO TO STEP 6

OK

4.

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

(a) Connect the Techstream to the DLC3.

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

HINT:

  • When performing the Active Test, make sure the shift lever is in P or N.
  • The A/C switch and all accessory switches should be off.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

(e) Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

HINT:

  • 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.

OK:

MAP and idling condition change in response to EGR step position as follows.

Standard:

-

EGR Step Position (Active Test)

0 Steps

0 to 30 Steps

Idling condition

Steady idling

Idling changes from steady to rough idling or engine stall

MAP

(Data List)

20 to 40 kPa (150 to 300 mmHg)

MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed
OK

GO TO STEP 19

NG

5.

INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly (See page ).

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

OK

GO TO STEP 19

NG

GO TO STEP 17

6.

REPAIR OR REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY

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

HINT:

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

NEXT

GO TO STEP 19

7.

CHECK PCV SYSTEM

(a) Check the PCV hose connections (See page ).

OK:

PCV hose is connected correctly and is not damaged.

NG

GO TO STEP 14

OK

8.

CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leak (See page ).

NG

GO TO STEP 15

OK

9.

INSPECT 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:

Air cleaner filter element is not excessively contaminated with dirt or oil.

NG

GO TO STEP 16

OK

10.

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

(a) Connect the Techstream to the DLC3.

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

HINT:

  • When performing the Active Test, make sure the shift lever is in P or N.
  • The A/C switch and all accessory switches should be off.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the EGR Step Position.

(e) Confirm the Throttle Idle Position is ON and check the engine idling condition and MAP values in the Data List while performing the Active Test.

HINT:

  • 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.

OK:

MAP and idling condition change in response to EGR step position as follows.

Standard:

-

EGR Step Position (Active Test)

0 Steps

0 to 30 Steps

Idling condition

Steady idling

Idling changes from steady to rough idling or engine stall

MAP

(Data List)

20 to 40 kPa (150 to 300 mmHg)

MAP value is at least +10 kPa (75 mmHg) higher than when EGR valve is fully closed
OK

GO TO STEP 12

NG

11.

INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly (See page ).

(b) Check if the EGR valve is stuck open.

OK:

EGR valve is tightly closed.

NG

GO TO STEP 17

OK

12.

PERFORM ACTIVE TEST USING TECHSTREAM

(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 P0011 inspection procedure (VVT system for intake side) (See page ).

(2) Perform the Active Test, referring to DTC P0014 inspection procedure (VVT system for exhaust side) (See page ).

NG

GO TO STEP 18

OK

13.

READ VALUE USING TECHSTREAM (MAF)

(a) Connect the Techstream to the DLC3.

(b) Start the engine and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF and Coolant Temp.

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

(e) Read MAF with the engine speed at 3000 rpm.

Standard:

Between 18.3 gm/sec. and 25.8 gm/sec. (shift lever: N; A/C: Off)

OK

GO TO STEP 19

NG

GO TO STEP 20

14.

REPAIR OR REPLACE PCV HOSE

(a) Repair or replace the PCV hose.

NEXT

GO TO STEP 19

15.

REPAIR OR REPLACE INTAKE SYSTEM

(a) Repair or replace the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system (See page ).

NEXT

GO TO STEP 19

16.

REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

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

NEXT

GO TO STEP 19

17.

REPLACE EGR VALVE ASSEMBLY

(a) Replace the EGR valve assembly (See page ).

HINT:

Perform "Inspection After Repair" after repairing or replacing the EGR valve assembly (See page ).

NEXT

GO TO STEP 19

18.

CHECK AND REPAIR VVT SYSTEM

(a) Check and repair the VVT system.

HINT:

  • Refer to DTC P0011 Inspection Procedure (VVT system for intake camshaft) (See page ).
  • Refer to DTC P0014 Inspection Procedure (VVT system for exhaust camshaft) (See page ).
NEXT

19.

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

NOTICE:

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

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs (See page ).

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

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

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

(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(j) Input the DTC: P050A.

(k) Check the DTC judgment result.

Result

Result

Proceed to

NORMAL

(DTC is not output)

A

ABNORMAL

(DTC P050A is output)

B
A

CHECK FOR INTERMITTENT PROBLEMS

B

20.

CHECK HARNESS AND CONNECTOR

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

HINT:

Repair any problems.

NEXT

21.

CHECK WHETHER DTC OUTPUT RECURS

NOTICE:

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

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs (See page ).

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

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

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

(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(j) Input the DTC: P050A.

(k) Check the DTC judgment result.

Result

Result

Proceed to

ABNORMAL

(DTC P050A is output)

A

NORMAL

(DTC is not output)

B
B

END
A

22.

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

(a) Disconnect the MAF meter 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

D7-3 (VG) - D74-74 (VG)

Always

Below 1 Ω

D7-2 (E2G) - D74-75 (E2G)

Always

Below 1 Ω

D7-3 (VG) or D74-74 (VG) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

23.

REPLACE MASS AIR FLOW METER

(a) Replace the mass air flow meter (See page ).

HINT:

  • If the result of the inspection performed in step 13 indicated no problem, proceed to the next step without replacing the mass air flow meter.
  • Perform "Inspection After Repair" after replacing the mass air flow meter (See page ).
NEXT

24.

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

NOTICE:

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

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs (See page ).

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

(f) Turn the ignition switch to ON and turn the Techstream on.

(g) Start the engine and warm it up.

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

(i) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

(j) Input the DTC: P050A.

(k) Check the DTC judgment result.

Result

Result

Proceed to

NORMAL

(DTC is not output)

A

ABNORMAL

(DTC P050A is output)

B
A

END
B

REPLACE ECM

    Evaporative Emission System Leak Detection Reference Orifice Low Flow (P043E,P043F,P2401,P2402,P2419)

    Cold Start Ignition Timing Performance (P050B)

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