Toyota Tundra. Manual — part 1581

PCV hose is connected correctly and is not damaged.

NG: REPAIR OR REPLACE PCV HOSE (See PCV VALVE )

OK: Go to Next Step

3. CHECK AIR INDUCTION SYSTEM

a. Check the air induction system for vacuum leakage (see ON-VEHICLE INSPECTION ).

OK:

No leakage from air induction system.

NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM (See REMOVAL )

OK: Go to Next Step

4. CHECK THROTTLE VALVE

a. Check the throttle valve condition.

OK:

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

NG: REPLACE THROTTLE BODY ASSEMBLY (See REMOVAL )

OK: REPLACE ECM (See REMOVAL )

DTC P050A COLD START IDLE AIR CONTROL SYSTEM PERFORMANCE

DESCRIPTION

DTC DETECTION CONDITION AND TROUBLE AREA REFERENCE CHART

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 set after the engine idles for 13 seconds (2 trip detection logic).

DTC

DTC Detection Condition

Trouble Area

P050A

Insufficient mass air flow at cold
start (2 trip detection logic)



Throttle body



Mass air flow meter



PCV hose



Air cleaner filter



Air induction system



VVT system



ECM

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

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 (PCM) measures the accumulated mass air flow at
engine idling. If it does not reach the criteria within 10 seconds, the ECM (PCM) 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 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.

Fig. 194: PO50A Detection Logic
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

MONITOR STRATEGY

NOTE:

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.
The ISC learning is performed when the engine is warmed up and has been
idling for 5 minutes.

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

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

Monitor runs whenever
following DTCs not present

P0010, P0020 (VVT Oil Control Valve)
P0011, P0021 (VVT System - Advance)
P0012, P0022 (VVT System - Retard)
P0016, P0018 (VVT System - Misalignment)
P0013, P0023 (Exhaust VVT Oil Control Valve)
P0014, P0024 (Exhaust VVT System - Advance)
P0015, P0025 (Exhaust VVT System - Retard)
P0017, P0019 (Exhaust VVT System - Misalignment)
P2195, P2196, P2197, P2198, P2237, P2238, P2239, P2240, P2241,
P2242, P2252, P2253, P2255, P2256, P2A00, P2A03 (Air Fuel Ratio
Sensor)
P0102, P0103 (Mass Air Flow Sensor)
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, P0174, P0175 (Fuel System)
P0301 - P0308 (Misfire)
P0335 (Crankshaft Position Sensor) P1340 (Camshaft Position Sensor)
P0340, P0342, P0343, P0345, P0347, P0348 (VVT Sensor)
P0365, P0367, P0368, P0390, P0392, P0393 (Exhaust VVT Sensor)
P0351 - P0358 (Igniter)
P0500 (Vehicle Speed Sensor)
P0705 (Shift Lever Position Switch)

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

3 seconds or more

Fuel-cut

OFF

Vehicle speed

Less than 3 km/h (1.875 mph)

Time after shift position

2 seconds or more

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS

INSPECTION PROCEDURE

1. CHECK DTCS

OK:

Any other DTCs are not set.

NG: GO TO DIAGNOSTIC TROUBLE CODE CHART

OK: Go to Next Step

2. CHECK THROTTLE BODY

a. Check for deposits around the throttle valve and throttle valve condition.

OK:

No deposits around throttle valve and throttle valve moves smoothly.

NG: Go to step 7

OK: Go to Next Step

3. CHECK VVT SYSTEM

a. Allow the engine to idle after the engine is warmed up.

b. Enter the following menus: Powertrain/Engine and ECT/Active Test/Control the VVT System

(Bank 1) or Control the VVT System (Bank 2).

c. Turn on Control the VVT System (Bank 1) or Control the VVT System (Bank 2) to advance the

valve timing.

d. Check the engine condition.

OK:

The engine stalls or idles roughly when Control the VVT System is ON (VVT system is OK).

NG: Go to step 8

changed
Atmospheric pressure

76 kPa (570 mmHg) or more

Accumulated mass air flow

Less than 60 g (varies with ECT)

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra