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 BODY

REPAIR OR REPLACE THROTTLE BODY

CHECK PCV SYSTEM

CHECK INTAKE SYSTEM

CHECK AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

PERFORM ACTIVE TEST USING TECHSTREAM (CONTROL THE VVT LINEAR)

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 (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 can be set 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 idle. 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 set 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 the negative battery terminal is disconnected during inspections or repairs, the idle speed control learning values are cleared. This DTC cannot be set with the idle speed control learning values cleared.

HINT:

The Idle speed control 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 after a cold start (2 trip detection logic)	Throttle body 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 body
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 are not present	P0010 (VVT 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) P0120, P0121 P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0125 (Insufficient Engine Coolant Temperature for Closed Loop Fuel Control) P014C, P014D, P015A, P015B, P2195, P2196, P2237, P2238, P2239, P2252, P2253 (Air Fuel Ratio Sensor - Sensor 1) P0171, P0172 (Fuel System) P0301, P0302, P0303, P0304 (Misfire) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0351, P0352, P0353, P0354 (Igniter) P0500 (Vehicle Speed Sensor)
Battery voltage	8 V or more
Time after engine start	3 seconds or more
Starter	Off
Engine coolant temperature at engine start	-10°C (14°F) or more
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 1.875 mph (3 km/h)
Atmospheric pressure	76 kPa(abs) [570 mmHg(abs)] or more

TYPICAL MALFUNCTION THRESHOLDS

Manual Transaxle Models

Accumulated mass air flow

Less than 27.5 g (Varies with engine coolant temperature)

Automatic Transaxle Models

Accumulated mass air flow

Less than 23.75 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 the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
   
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 / Primary / 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 the 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 (COROLLA_ZRE142 RM000000PDK0ZBX.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 (Link).

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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

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
   P050A	A
   P050A and other DTCs	B

   HINT:

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

B	GO TO DTC CHART (COROLLA_ZRE142 RM000000PDF0G9X.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 and warm it up.
   

3. Turn the Techstream on.
   

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

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

6. Add together the Short FT #1 and Long FT #1 values to obtain the total Fuel Trim.
   

   OK:

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

NG	Go to step 5

OK

3.INSPECT THROTTLE BODY

1. Check for deposits around the throttle valve and check the throttle valve condition.
   

   OK:

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

   
   

   Result:

   
   

   Result	Proceed to
   NG	A
   OK	B

B	Go to step 14

A

4.REPAIR OR REPLACE THROTTLE BODY

1. Repair or replace the throttle body (COROLLA_ZRE142 RM0000017UC03CX.html).
   

NEXT	Go to step 14

5.CHECK PCV SYSTEM

1. Check the PCV hose connections.
   

OK:

PCV hose is connected correctly and is not damaged.

NG	Go to step 10

OK

6.CHECK INTAKE SYSTEM

1. Check the intake system for vacuum leaks (COROLLA_ZRE142 RM00000341100ZX.html).
   

   OK:

   No leakage 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:

   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 (CONTROL THE VVT LINEAR)

1. 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 (COROLLA_ZRE142 RM000000PDU0PSX_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 / Primary / MAF, Coolant Temp and Engine Speed.
   

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

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

   Standard Value:

   Between 7.6 gm/s and 11.4 gm/s (Shift lever: Neutral, A/C: off)
   

OK	Go to step 14
NG	Go to step 15

10.REPAIR OR REPLACE PCV HOSE

1. Repair or replace the PCV hose.
   

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:

   1. Refer to DTC P0011 Inspection Procedure (COROLLA_ZRE142 RM000000PDU0PSX_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 Techstream to the DLC3.
   

2. Turn the ignition switch to ON.
   

3. Turn the Techstream on.
   

4. Clear the DTCs (COROLLA_ZRE142 RM000000PDK0ZBX.html).
   

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

6. Turn the ignition switch to ON and turn the Techstream on.
   

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

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

9. Start the engine and warm it up.
   

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

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

12. Input the DTC: P050A.
    

13. Check the DTC judgment result.
    
    

    Result:

    
    

    Result	Proceed to
    NORMAL (No output)	A
    ABNORMAL (P050A)	B

B	Go to step 15

A
END

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 (COROLLA_ZRE142 RM000000UZ30C8X.html).
   

   HINT:

   Repair any problems.

NEXT

16.CHECK WHETHER DTC OUTPUT RECURS (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 (COROLLA_ZRE142 RM000000PDK0ZBX.html).
   

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

6. Turn the ignition switch to ON and turn the Techstream on.
   

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

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

9. Start the engine and warm it up.
   

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

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

12. Input the DTC: P050A.
    

13. Check the DTC judgment result.
    
    

    Result:

    
    

    Result	Proceed to
    ABNORMAL (P050A)	A
    NORMAL (No 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
   B2-5 (VG) - B31-118 (VG)	Always	Below 1 Ω
   B2-4 (E2G) - B31-116 (E2G)

   
   

   Standard Resistance (Check for Short):

   
   

   Tester Connection	Condition	Specified Condition
   B2-5 (VG) or B31-118 (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 (MASS AIR FLOW METER - ECM)

OK

18.REPLACE MASS AIR FLOW METER

1. Replace the mass air flow meter (COROLLA_ZRE142 RM0000017TX03AX.html).
   

   HINT:

   If the result of the inspection 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 the DTCs (COROLLA_ZRE142 RM000000PDK0ZBX.html).
   

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

6. Turn the ignition switch to ON and turn the Techstream on.
   

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

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

9. Start the engine and warm it up.
   

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

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

12. Input the DTC: P050A.
    

13. Check the DTC judgment result.
    
    

    Result:

    
    

    Result	Proceed to
    NORMAL (No output)	A
    ABNORMAL (P050A)	B

B	REPLACE ECM (COROLLA_ZRE142 RM000002WT402ZX.html)

A
END