Toyota Tundra. Manual — part 1545

HINT:



When DTC P0171 or P0174 is stored, the actual air-fuel ratio is on the lean side. When DTC P0172 or
P0175 is stored, the actual air-fuel ratio is on the rich side.



If the vehicle runs out of fuel, the air-fuel ratio is lean and DTC P0171 or P0174 may be stored. The MIL
is then illuminated.

MONITOR DESCRIPTION

During air-fuel ratio feedback, if the short term fuel trim deviates from 1.0 by a large amount, the alcohol
concentration learned value is updated (for example, if the short term fuel trim is more than 1.0, the alcohol
concentration learned value increases), and then the short term fuel trim deviation is reflected in the long term
fuel trim.

Example:

The aggregate fuel trim value is +87% or more or -35% or less, the ECM interprets this as a fuel system
malfunction and stores a DTC.

P0172
P0175

With warm engine and stable air-
fuel ratio feedback, fuel trim
considerably in error to rich side
(2 trip detection logic)



ECT sensor



Ignition system



Fuel pressure



Gas leak from exhaust
system



Open or short in A/F sensor
(for Sensor 1) circuit



A/F sensor (for Sensor 1)



A/F sensor heater (for Sensor
1)



Integration relay



A/F sensor heater and
integration relay circuits



ECM



Fuel pressure switching valve



Fuel pressure regulator



Fuel pressure regulator for
high pressure



Fuel pump



Fuel pump ECU

2009 Toyota Tundra

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

Fig. 106: Fuel Compensation Amount Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

Related DTCs

P0171: Fuel trim lean (for Bank 1)
P0172: Fuel trim rich (for Bank 1)
P0174: Fuel trim lean (for Bank 2)
P0175: Fuel trim rich (for Bank 2)

Required Sensors/Components
(Main)

A/F sensor

Required Sensors/Components
(Related)

Mass air flow meter, Engine Coolant Temperature Sensor,
Crankshaft position sensor

Frequency of Operation

Continuous

Duration

Within 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)
P0031, P0032, P0051, P0052 (Air Fuel Ratio Sensor Heater)
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

2009 Toyota Tundra

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

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

Fig. 107: Vehicle Speed Driving Pattern
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

(Throttle Position Sensor)
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)
P0412, P0415, P0418, P0419, P1613, P1614 (Secondary Air
Injection System Control)
P2440, P2441, P2442, P2443, P2444, P2445, P2446, P2447
(Secondary Air Injection System)
P0500 (Vehicle Speed Sensor)

Fuel system status

Closed loop

Battery voltage

11 V or more

Either of following conditions 1 or 2
set

-

1. Engine speed

Below 1100 RPM

2. Intake air amount per revolution

0.36 g/rev or more

Catalyst monitor

Not executed

Purge-cut

Executing

Either of following conditions 1 or 2 met

-

1. Average of the aggregate fuel trim*

87% or more (varies with ECT)

2. Average of the aggregate fuel trim*

-35% or less (varies with ECT)

HINT:
*: Aggregate fuel trim is approximately equal to the following: Short FT + ((1 + Long FT/100) x (1 +
(Alcohol Density Estimate/2/100)) -1) x 100

2009 Toyota Tundra

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

1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON.

3. Turn the Techstream on.

4. Clear the DTCs (See DTC CHECK/CLEAR ).

HINT:

Even if no DTCs are stored, perform the DTC clear operation to start alcohol concentration learning.

5. Start the engine.

HINT:

After clearing the DTCs, the engine becomes difficult to start if the concentration of alcohol in the fuel is
high. Therefore, it may be necessary to crank the engine a few times before it starts.

6. Warm it up until the ECT reaches 75°C (167°F) or higher [A].

7. Drive the vehicle at 32 km/h (20 mph) or more and maintain a constant speed for 2 minutes or more [B].

HINT:

Make sure that the Data List "Alcohol Density Learning" is "Compl".

8. Drive the vehicle at between 60 km/h and 120 km/h (38 mph and 75 mph) and at an engine speed of

between 1400 RPM and 3200 RPM for 5 minutes or more [C].

HINT:

If the system is still malfunctioning, pending DTCs are stored during step [C].

WIRING DIAGRAM

Refer to DTC P2195 .

INSPECTION PROCEDURE

HINT:



Read freeze frame data using the Techstream. Freeze frame data records the engine condition when
malfunctions are detected. 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.

CAUTION: Perform this drive pattern on a level road as much as possible and

strictly observe the posted speed limits and traffic laws while driving.

2009 Toyota Tundra

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