Toyota Tundra Service Manual: 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.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

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

(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.

HINT:

If any DTCs other than P050A are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

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

(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

(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:

OK

GO TO STEP 19

NG

(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

(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

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

OK:

PCV hose is connected correctly and is not damaged.

NG

GO TO STEP 14

OK

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

NG

GO TO STEP 15

OK

(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

(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:

OK

GO TO STEP 12

NG

(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

(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

(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

(a) Repair or replace the PCV hose.

NEXT

GO TO STEP 19

(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

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

NEXT

GO TO STEP 19

(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

(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

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.

A

CHECK FOR INTERMITTENT PROBLEMS

B

(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

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.

B

END

A

(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:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(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

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.

A

END

B

REPLACE ECM