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 OCV)

READ VALUE USING TECHSTREAM (MAF)

REPAIR OR REPLACE PCV SYSTEM

REPAIR OR REPLACE INTAKE SYSTEM

REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

CHECK AND REPAIR VVT SYSTEM

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED (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 lower than 50°C (122°F), the ECM measures the accumulated mass air flow at engine idling. If it 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 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 negative battery terminal is disconnected during inspections or repairs, the ISC (Idle Speed Control) learning values are cleared. This DTC cannot be stored with the ISC learning values cleared.

HINT:

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 system Air cleaner filter element Intake system VVT system Wire harness and 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 (ECT) 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 (VVT OCV) P0011 (VVT system 1 - advance) P0012 (VVT system 1 - retard) P0016 (VVT system 1 - misalignment) P0100, P0102, P0103 (MAF meter) P0115, P0117, P0118 (ECT sensor) P0120 - P0123, P0220, P0222, P0223, P2135 (TP sensor) P0125 (Insufficient ECT for closed loop) P0171, P0172 (Fuel system) P0301 - P0304 (Misfire) P0335 (CKP sensor) P0340 (CMP sensor) P0351 - P0354 (Ignitor) P0500 (VSS) P0705 (Shift position switch) P2195, P2196 (A/F sensor) P2237 - P2239, P2252, P2253 (A/F sensor) P2A00 (A/F sensor)
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 time	3 seconds or more
Fuel cut	OFF
Vehicle speed	Less than 3 km/h (1.875 mph)
Atmospheric pressure	76 kPa (570 mmHg) or more
Time after shift position changed	1 second or more

TYPICAL MALFUNCTION THRESHOLDS

Accumulated mass air flow

Varies with ECT (Example: Less than 21.8 g)

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 ABNORMAL, the system has a malfunction.
       
    2. If the 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 RM000000PDK0QGX.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 P0102 (YARIS_NCP93 RM000000U5B0ITX_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 RM000000PDF0E6X.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 while the engine is idling.
   

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.
   

   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 throttle with motor body assembly (YARIS_NCP93 RM000001CZA012X.html).
   

NEXT	Go to step 14

5.CHECK PCV SYSTEM

1. Check the PCV hose connections (YARIS_NCP93 RM000001L6B007X.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 RM0000032ZM008X.html).
   

   OK:

   No leak 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 is not excessively contaminated with dirt or oil.
   

   OK:

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

NG	Go to step 12

OK

8.PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE OCV)

1. Connect the Techstream to the DLC3.
   

2. Start the engine and turn the Techstream on.
   

3. Turn the Techstream on.
   

4. Turn the A/C switch on.
   

5. Warm up the engine.
   

6. On the Techstream, enter the following menu: Powertrain / Engine and ECT / Active Test / Control the VVT Linear (Bank 1).
   

7. Check the engine speed while operating the Oil Control Valve (OCV) using the Techstream.
   
   

   OK:

   
   

   Techstream Operation	Specified Condition
   0%	Normal engine speed
   100%	Engine idles roughly or stalls

   HINT:

   Refer to "Data List / Active Test" [VVT OCV Duty #1 and VVT Change Angle #1] (YARIS_NCP93 RM000000PDN0J9X.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 2500 rpm.
   
   

   Standard:

   
   

   Techstream Display	Condition	Specified Condition
   MAF	Shift lever position: N A/C: Off Engine Speed: 2500 rpm	Between 2 gm/sec, and 6 gm/sec.

OK	Go to step 14
NG	Go to step 15

10.REPAIR OR REPLACE PCV SYSTEM

1. Repair or replace the PCV system.
   

NEXT	Go to step 14

11.REPAIR OR REPLACE INTAKE SYSTEM

1. Repair or replace the intake system.
   

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 RM000000PDU0JZX_08.html)

NEXT

14.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED (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 DTCs (YARIS_NCP93 RM000000PDK0QGX.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 RM000000PDQ0NOX.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 a Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear DTCs (YARIS_NCP93 RM000000PDK0QGX.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 (Check for Open):

   Tester Connection	Condition	Specified Condition
   C26-3 (VG) - C20-118 (VG)	Always	Below 1 Ω
   C26-2 (E2G) - C20-116 (E2G)

   Standard Resistance (Check for Short):

   Tester Connection	Condition	Specified Condition
   C26-3 (VG) or C20-118 (VG) - Body ground	Always	10 kΩ or higher

4. Reconnect the mass air flow meter connector.
   

5. Reconnect the ECM connector.
   

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

18.REPLACE MASS AIR FLOW METER

1. Replace the mass air flow meter (YARIS_NCP93 RM000001D0L00WX.html).
   

   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.

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 DTCs (YARIS_NCP93 RM000000PDK0QGX.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

A
END