Toyota Corolla Cross: Cold Start Idle Control System Performance (P050A00)

MONITOR DESCRIPTION

A monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). If certain conditions are met, a DTC will be stored after the engine idles for 13 seconds (2 trip detection logic).

This DTC is designed to monitor the idle air control at cold start. When the engine is started at an engine coolant temperature of less than 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, illuminates the MIL and stores this DTC.

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:

The idle speed control learned values are cleared by performing learning value reset. Idle speed control learning needs to be performed before this DTC can be stored.

HINT:

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

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Note
P050A00	Cold Start Idle Control System Performance	Insufficient mass air flow after a cold start (2 trip detection logic).	Throttle body with motor assembly Mass air flow meter sub-assembly PCV system Air cleaner filter element sub-assembly Intake system VVT system EGR valve assembly Wire harness or connector ECM	Comes on	SAE Code: P050A DTC for Mexico Models: Does not apply

MONITOR STRATEGY

Related DTCs	P050A: Cold start idle air speed control system
Required Sensors/Components (Main)	Throttle body with motor assembly
Required Sensors/Components (Related)	Engine coolant temperature sensor Mass air flow meter sub-assembly
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 the following DTCs are not stored	P0010, P1360, P1362, P1364, P1366, P2614 (Motor drive VVT system control module) P0011 (VVT system - advance) P0012 (VVT system - retard) P0013 (Exhaust VVT oil control solenoid) P0014 (Exhaust VVT system - advance) P0015 (Exhaust VVT system - retard) P0016 (VVT system - misalignment) P0017 (Exhaust VVT system - misalignment) P0087, P0088, P0191, P0192, P0193 (Fuel pressure sensor (for high pressure side)) P0101, P0102, P0103 (Mass air flow meter) P0107, P0108 (Manifold absolute pressure) P0116, P0117, P0118 (Engine coolant temperature sensor) P0121, P0122, P0123, P0222, P0223, P2135 (Throttle position sensor) P0125 (Insufficient 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) P0201, P0202, P0203, P0204, P062D, P21CF, P21D0, P21D1, P21D2 (Fuel injector) P0300, P0301, P0302, P0303, P0304 (Misfire) P0335, P0337, P0338 (Crankshaft position sensor) P0340, P0342, P0343 (Camshaft position sensor) P0365, P0367, P0368 (Exhaust camshaft position sensor) P0400 (EGR system) P0401 (EGR system (closed)) P0500 (Vehicle speed sensor) P0657, P0658, P2102, P2103, P2111, P2112, P2119 (Throttle actuator) P107B, P107C, P107D (Fuel pressure sensor (for low pressure side)) P11EA, P11EC, P11ED, P11EE, P11EF, P219A, P219C, P219D, P219E, P219F (Air-fuel ratio imbalance) P1235 (High pressure fuel pump circuit) P2228, P2229 (Atmospheric pressure sensor)
Auxiliary 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°C (14°F) or higher, and less than 50°C (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	1 second or more
Atmospheric pressure	76 kPa(abs) [11 psi(abs)] or higher

TYPICAL MALFUNCTION THRESHOLDS

Accumulated mass air flow

Less than 60 g (varies with engine coolant temperature and engine coolant temperature at engine start)

CONFIRMATION DRIVING PATTERN

HINT:

• After repair has been completed, clear the DTC and then check that the vehicle has returned to normal by performing the following All Readiness check procedure.

  Click here

• When clearing the permanent DTCs, refer to the "CLEAR PERMANENT DTC" procedure.

  Click here

1. Connect the GTS to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the GTS on.
4. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
5. Turn the ignition switch off and wait for at least 30 seconds.
6. Start the engine and warm it up for 5 minutes or more.
7. Stop the engine.
8. Leave the vehicle outside overnight.
9. Turn the ignition switch to ON [A].
10. Turn the GTS on.
11. Enter the following menus: Powertrain / Engine / Data List / Coolant Temperature.
12. Check that the value of the Data List item Coolant Temperature is between -10 and 50°C (14 and 122°F).
13. Start the engine and warm it up until the engine coolant temperature is the same as the coolant temperature in the Freeze Frame Data.
14. Idle the engine for 1 minute or more [B].
15. Enter the following menus: Powertrain / Engine / Trouble Codes [C].
16. 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.
17. Enter the following menus: Powertrain / Engine / Utility / All Readiness.
18. Input the DTC: P050A00.
19. Check the DTC judgment result.

    GTS 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

    HINT:

    • If the judgment result is NORMAL, the system is normal.
    • If the judgment result is ABNORMAL, the system is malfunctioning.
    • If the judgment result is INCOMPLETE, idle the engine for 3 minutes, let the engine cool down, and then perform steps [A] through [B] again.
    • Idle the engine for 3 minutes, let the engine cool down, and then perform steps [A] through [C]: Normal judgment procedure.

      The normal judgment procedure is used to complete DTC judgment and also used when clearing permanent DTCs.

    • When clearing the permanent DTCs, do not disconnect the cable from the auxiliary battery terminal or attempt to clear the DTCs during this procedure, as doing so will clear the universal trip and normal judgment histories.

WIRING DIAGRAM

Refer to DTC P010012.

Click here

CAUTION / NOTICE / HINT

NOTICE:

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

HINT:

Read Freeze Frame Data using the GTS. 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 moving or stationary, 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.

PROCEDURE

1.	CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P050A00)

(a) Read the DTCs.

Powertrain > Engine > Trouble Codes

Result	Proceed to
DTC P050A00 is output	A
DTC P050A00 and other DTCs are output	B

HINT:

If any DTCs other than P050A00 are output, troubleshoot those DTCs first.

B

GO TO DTC CHART

A

2.	READ VALUE USING GTS (FUEL TRIM)

HINT:

Calculate the total fuel trim values to check the characteristic deviation of the mass air flow meter sub-assembly.

(a) Start the engine.

(b) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Short FT B1S1
Long FT B1S1

(c) Read the values displayed on the GTS at engine idle.

(d) Add the Short FT B1S1 and Long FT B1S1 values to obtain the total fuel trim.

Standard:

GTS Display	Specified Condition
Total of Short FT B1S1 and Long FT B1S1	Between -20 and 20%

NG

GO TO STEP 7

OK

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

(a) Check for foreign matter between the throttle valve and housing. If necessary, clean the throttle body with motor assembly. Also, check that the throttle valve moves smoothly.

OK:

Throttle valve is not contaminated with foreign matter and moves smoothly.

NG

GO TO STEP 6

OK

4.	PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

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

HINT:

The A/C switch and all accessories should be off.

(b) Enter the following menus.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Engine Speed
Intake Manifold Absolute Pressure
Coolant Temperature

(c) Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.

NOTICE:

• 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.
• Do not open the EGR valve 30 steps or more during the Active Test.

OK:

The value of Intake Manifold Absolute Pressure and Engine Speed change in response to EGR step position.

Standard:

-	Control the EGR Step Position (Active Test)
	0 Steps	0 to 30 Steps
Idling condition	Steady idling	Idling changes from steady to rough idling or engine stalls
Intake Manifold Absolute Pressure (Data List)	Intake Manifold Absolute Pressure value is 18 to 38 kPa(abs) (2.6 to 5.5 psi(abs)) (EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

HINT:

During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

OK

GO TO STEP 14

NG

5.	INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly.

Click here

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

OK:

EGR valve is tightly closed.

OK

GO TO STEP 14

NG

GO TO STEP 17

6.	REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY

Click here

HINT:

Perform "Inspection After Repair" after replacing the throttle body with motor assembly.

Click here

NEXT

GO TO STEP 21

7.	CHECK PCV VALVE AND HOSE CONNECTIONS

(a) Check the PCV hose connections.

(b) Check the PCV valve.

Click here

OK:

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

NG

GO TO STEP 20

OK

8.	CHECK INTAKE SYSTEM

(a) Check the intake system for vacuum leaks.

Click here

OK:

No leaks from intake system.

NG

GO TO STEP 19

OK

9.	CHECK 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:

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

NG

GO TO STEP 18

OK

10.	PERFORM ACTIVE TEST USING GTS (CONTROL THE EGR STEP POSITION)

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

HINT:

The A/C switch and all accessories should be off.

(b) Enter the following menus.

Powertrain > Engine > Active Test

Active Test Display
Control the EGR Step Position

Data List Display
Engine Speed
Intake Manifold Absolute Pressure
Coolant Temperature

(c) Check the engine idling condition and Intake Manifold Absolute Pressure values in the Data List while performing the Active Test.

NOTICE:

• 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.
• Do not open the EGR valve 30 steps or more during the Active Test.

OK:

The value of Intake Manifold Absolute Pressure and Engine Speed change in response to EGR step position.

Standard:

-	Control the EGR Step Position (Active Test)
	0 Steps	0 to 30 Steps
Idling condition	Steady idling	Idling changes from steady to rough idling or engine stalls
Intake Manifold Absolute Pressure (Data List)	Intake Manifold Absolute Pressure value is 18 to 38 kPa(abs) (2.6 to 5.5 psi(abs)) (EGR valve is fully closed)	Intake Manifold Absolute Pressure value is at least +10 kPa (1.45 psi) higher than when EGR valve is fully closed

HINT:

During Active Test, if the idling condition does not change in response to EGR step position, then there is probably a malfunction in the EGR valve.

OK

GO TO STEP 12

NG

11.	INSPECT EGR VALVE ASSEMBLY

(a) Remove the EGR valve assembly.

Click here

(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 GTS (CHECK VVT SYSTEM)

(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 P001100 Procedure (VVT-iE system for intake camshaft).

Click here

(2) Perform the Active Test, referring to DTC P001400 Procedure (VVT-i system for exhaust camshaft).

Click here

NG

GO TO STEP 16

OK

13.	READ VALUE USING GTS (MASS AIR FLOW SENSOR)

(a) Start the engine.

(b) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Engine Speed
Mass Air Flow Sensor
Coolant Temperature

(c) Allow the engine to idle until Coolant Temperature is 75°C (167°F) or higher.

(d) Read Mass Air Flow Sensor while maintaining an engine speed of 3000 rpm.

Standard:

GTS Display	Condition	Specified Condition
Mass Air Flow Sensor	Engine warmed up Shift position: P A/C: Off Engine Speed: 3000 rpm	Between 8.0 and 13.0 gm/sec

NG

GO TO STEP 23

OK

14.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

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

NEXT

15.	CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

(a) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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

(c) Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.

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

(e) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(f) Input the DTC: P050A00.

(g) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050A00 is output)	B

A

CHECK FOR INTERMITTENT PROBLEMS

B

GO TO STEP 23

16.	CHECK AND REPAIR VVT SYSTEM

(a) Check and repair the VVT system.

HINT:

• Refer to DTC P001100 Inspection Procedure (VVT-iE system for intake camshaft).

  Click here

• Refer to DTC P001400 Inspection Procedure (VVT-i system for exhaust camshaft).

  Click here

NEXT

GO TO STEP 21

17.	REPLACE EGR VALVE ASSEMBLY

Click here

HINT:

Perform "Inspection After Repair" after replacing the EGR valve assembly.

Click here

NEXT

GO TO STEP 21

18.	REPLACE AIR CLEANER FILTER ELEMENT SUB-ASSEMBLY

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

NEXT

GO TO STEP 21

19.	REPAIR OR REPLACE INTAKE SYSTEM

(a) Repair or replace the intake system.

HINT:

Perform "Inspection After Repair" after repairing or replacing the intake system.

Click here

NEXT

GO TO STEP 21

20.	REPAIR OR REPLACE PCV VALVE OR HOSE

(a) Repair or replace PCV valve or hose.

NEXT

21.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

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

NEXT

22.	CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

(a) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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

(c) Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.

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

(e) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(f) Input the DTC: P050A00.

(g) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050A00 is output)	B

A

END

B

23.	CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY CONNECTOR CONNECTION)

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

Click here

HINT:

Repair any problems.

NEXT

24.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

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

NEXT

25.	CHECK WHETHER DTC OUTPUT RECURS (DTC P050A00)

NOTICE:

In this operation, the engine must be cold (approximately the same as the engine coolant temperature recorded in the Freeze Frame Data).

(a) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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

(c) Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.

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

(e) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(f) Input the DTC: P050A00.

(g) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050A00 is output)	B

A

END

B

26.	CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)

(a) Disconnect the mass air flow meter sub-assembly 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
C26-3 (VCC) - C76-78 (VCVG)	Always	Below 1 Ω
C26-1 (FG) - C76-101 (VG)	Always	Below 1 Ω
C26-2 (E2G) - C76-79 (E2G)	Always	Below 1 Ω
C26-3 (VCC) or C76-78 (VCVG) - Body ground and other terminals	Always	10 kΩ or higher
C26-1 (FG) or C76-101 (VG) - Body ground and other terminals	Always	10 kΩ or higher
C26-2 (E2G) or C76-79 (E2G) - Body ground and other terminals	Always	10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

27.	REPLACE MASS AIR FLOW METER SUB-ASSEMBLY

Click here

HINT:

• If the result of the inspection performed in step 13 (READ VALUE USING GTS (MASS AIR FLOW SENSOR)) indicated no problem, proceed to the next step without replacing the mass air flow meter sub-assembly.
• Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly.

  Click here

NEXT

28.

CLEAR DTC

(a) Clear the DTCs.

Powertrain > Engine > Clear DTCs

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

NEXT

29.	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).

(a) Enter the following menus.

Powertrain > Engine > Data List

Tester Display
Coolant Temperature

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

(c) Start the engine and warm it up until the engine coolant temperature is the same as the engine coolant temperature in the Freeze Frame Data.

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

(e) Enter the following menus.

Powertrain > Engine > Utility

Tester Display
All Readiness

(f) Input the DTC: P050A00.

(g) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P050A00 is output)	B

A

END

B

REPLACE ECM

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