Dtc P050A Cold Start Idle Air Control System Performance

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A)

READ VALUE USING TECHSTREAM (FUEL TRIM)

INSPECT THROTTLE WITH MOTOR BODY ASSEMBLY (THROTTLE VALVE)

REPAIR OR REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY

CHECK PCV SYSTEM

CHECK INTAKE SYSTEM

CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

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

READ VALUE USING TECHSTREAM (MAF)

REPAIR OR REPLACE PCV HOSE

REPAIR OR REPLACE INTAKE SYSTEM

REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

CHECK AND REPAIR VVT SYSTEM

CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)

CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)

CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)

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

REPLACE MASS AIR FLOW METER

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

DTC P050A Cold Start Idle Air Control System Performance

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 below 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 a 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:

When performing the Learning Value Reset* during inspections or repairs, the idle speed control learned values are cleared. This DTC cannot be stored with the idle speed control learned values cleared.

HINT:

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

*: Refer to Initialization (YARIS_NCP93 RM000004NJD006X.html).

DTC No.	DTC Detection Condition	Trouble Area
P050A	Insufficient mass air flow after a cold start (2 trip detection logic).	Throttle with motor body assembly Mass air flow meter PCV system Air cleaner filter element Intake system VVT system Wire harness or connector ECM

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 (Camshaft Timing Oil Control Valve) P0011 (VVT System - Advance) P0012 (VVT System - Retard) P0016 (VVT System - Misalignment) P0102, P0103 (Mass Air Flow Meter) P0115, P0117, P0118 (Engine Coolant Temperature Sensor) P0125 (Insufficient Coolant Temperature for Closed Loop Fuel Control) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0171, P0172 (Fuel System) P0301 - P0304 (Misfire) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0351 - P0354 (Igniter) P0500 (Vehicle Speed Sensor) P0705 (Shift Lever Position Switch) P2195, P2196, P2237, P2238, P2239, P2252, P2253, P014C, P014D, P015A, P015B (Air Fuel Ratio Sensor) P219A (Air Fuel Ratio Imbalance)
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 to 50°C (14 to 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 (only for Automatic Transaxle)	1 second or more
Atmospheric pressure	76 kPa(abs) [570 mmHg(abs)] or higher

TYPICAL MALFUNCTION THRESHOLDS

Accumulated mass air flow

Manual Transaxle: Less than 33.125 g (varies with engine coolant temperature) Automatic Transaxle: Less than 30 g (varies with engine coolant temperature)

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 [B].
   
10. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
    
11. Read pending DTCs.
    

    HINT:

    1. If a pending DTC is output, the system is malfunctioning.
       
    2. 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.
    
    

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

    HINT:

    1. If the judgment result shows NORMAL, the system is normal.
       
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
       
    3. 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 [C] again.
       
15. If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
    

    HINT:

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

WIRING DIAGRAM

Refer to DTC P0102 (YARIS_NCP93 RM000000U5B0KEX_07.html).

INSPECTION PROCEDURE

NOTICE:

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

1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A)

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
   

5. Read 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 (YARIS_NCP93 RM000000PDF0EWX.html)

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.

1. Connect the Techstream to the DLC3.
   

2. Start the engine.
   

3. Turn the Techstream on.
   

4. Enter the following menus: Powertrain / Engine and ECT / Data List / Short FT #1 and Long FT #1.
   

5. Read the values displayed on the Techstream at engine idle.
   

6. Add together the Short FT #1 and Long FT #1 values to obtain the total fuel trim.
   

   Standard:

   Total of Short FT #1 and Long FT #1 values is between -20% and 20%.
   

NG	Go to step 5

OK

3.INSPECT THROTTLE WITH MOTOR BODY ASSEMBLY (THROTTLE VALVE)

1. 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 14
NG	Go to step 4

4.REPAIR OR REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY

1. Repair or replace the throttle with motor body assembly (YARIS_NCP93 RM000003VHR00IX.html).
   

   HINT:

   Perform "Inspection After Repair" after repairing or replacing the throttle with motor body assembly (YARIS_NCP93 RM000004NJD006X.html).

NEXT	Go to step 14

5.CHECK PCV SYSTEM

1. Check the PCV hose connections (YARIS_NCP93 RM000001RN103YX.html).
   

   OK:

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

NG	Go to step 10

OK

6.CHECK INTAKE SYSTEM

1. Check the intake system for vacuum leaks (YARIS_NCP93 RM000004VL8003X.html).
   

   OK:

   No leaks from the intake system.
   

NG	Go to step 11

OK

7.CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

1. 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)

1. Operate the VVT system through the Active test, and check if the VVT system is operating normally.
   

   HINT:

   Perform the Active Test, referring to DTC P0011 inspection procedure (YARIS_NCP93 RM000000PDU0LTX_09_0002.html).

NG	Go to step 13

OK

9.READ VALUE USING TECHSTREAM (MAF)

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF, Coolant Temp and Engine Speed.
   

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

6. Read MAF with the engine speed at 3000 rpm.
   
   

   Standard:

   
   

   Techstream Display	Condition	Specified Condition
   MAF	Shift lever position: N A/C: Off Engine Speed: 3000 rpm	Between 4 gm/sec. and 10 gm/sec.

OK	Go to step 14
NG	Go to step 15

10.REPAIR OR REPLACE PCV HOSE

1. Repair or replace the PCV valve or hose (YARIS_NCP93 RM000001RN204OX.html).
   

NEXT	Go to step 14

11.REPAIR OR REPLACE INTAKE SYSTEM

1. Repair or replace the intake system.
   

   HINT:

   Perform "Inspection After Repair" after repairing or replacing the intake system (YARIS_NCP93 RM000004NJD006X.html).

NEXT	Go to step 14

12.REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

1. Replace the air cleaner filter element sub-assembly.
   

NEXT	Go to step 14

13.CHECK AND REPAIR VVT SYSTEM

1. Check and repair the VVT system.
   

   HINT:

   Refer to DTC P0011 Inspection Procedure (YARIS_NCP93 RM000000PDU0LTX_08.html).

NEXT

14.CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)

NOTICE:

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

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
   

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

6. Turn the ignition switch to ON.
   

7. Turn the Techstream on.
   

8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
   

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

10. Start the engine and warm it up.
    

11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    

12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    

13. Input the DTC: P050A.
    

14. Check the DTC judgment result.
    

    Result

    Result	Proceed to
    NORMAL (DTC is not output)	A
    ABNORMAL (DTC P050A is output)	B

B	Go to step 15

A
CHECK FOR INTERMITTENT PROBLEMS (YARIS_NCP93 RM000000PDQ0Q2X.html)

15.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER CONNECTOR CONNECTION)

1. Check the connection and terminal contact pressure of connectors and wire harnesses between the mass air flow meter and ECM (YARIS_NCP93 RM000000UZ309WX.html).
   

   HINT:

   Repair any problems.

NEXT

16.CHECK WHETHER DTC OUTPUT RECURS (DTC P050A)

NOTICE:

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

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
   

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

6. Turn the ignition switch to ON.
   

7. Turn the Techstream on.
   

8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
   

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

10. Start the engine and warm it up.
    

11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    

12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    

13. Input the DTC: P050A.
    

14. Check the DTC judgment result.
    

    Result

    Result	Proceed to
    ABNORMAL (DTC P050A is output)	A
    NORMAL (DTC is not output)	B

B	END

A

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

1. Disconnect the mass air flow meter connector.
   

2. Disconnect the ECM connector.
   

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

   Standard Resistance:

   
   

   Tester Connection	Condition	Specified Condition
   C63-3 (VG) - C51-91 (VG)	Always	Below 1 Ω
   C63-2 (E2G) - C51-92 (E2G)	Always	Below 1 Ω
   C63-3 (VG) or C51-91 (VG) - Body ground	Always	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

18.REPLACE MASS AIR FLOW METER

1. Replace the mass air flow meter (YARIS_NCP93 RM000003VI000HX.html).
   

   HINT:

   1. 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.
      
   2. Perform "Inspection After Repair" after replacing the mass air flow meter (YARIS_NCP93 RM000004NJD006X.html).
      

NEXT

19.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

NOTICE:

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

1. Connect the Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).
   

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

6. Turn the ignition switch to ON.
   

7. Turn the Techstream on.
   

8. Enter the following menus: Powertrain / Engine and ECT / Data List / Coolant Temp.
   

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

10. Start the engine and warm it up.
    

11. Drive the vehicle in accordance with the driving pattern described in Confirmation Driving Pattern.
    

12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
    

13. Input the DTC: P050A.
    

14. Check the DTC judgment result.
    

    Result

    Result	Proceed to
    NORMAL (DTC is not output)	A
    ABNORMAL (DTC P050A is output)	B

B	REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

A
END