Toyota Tundra. Manual — part 1182

Fig. 91: Diagnosis For Fuel System

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

Fuel-trim:

TYPICAL ENABLING CONDITIONS

Related DTCs

P0171: Fuel trim Lean (bank 1)
P0172: Fuel trim Rich (bank 1)
P0174: Fuel trim Lean (bank 2)
P0175: Fuel trim Rich (bank 2)

Required Sensors/Components (Main)

Fuel system

Required Sensors/Components (Related)

A/F sensor. Mass air flow meter, Crankshaft position sensor

Frequency of Operation

Continuous

Duration

Within 10 seconds

MIL Operation

2 driving cycles

Sequence of Operation

None

P0010, P0020 (OCV Bank 1, 2)
P0011 (VVT System 1 - Advance)
P0012 (VVT System 1 - Retard)
P0021 (VVT System 2 - Advance)
P0022 (VVT System 2 - Retard)
P0031, P0032, P0051, P0052 (A/F sensor heater -

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS

Fuel-trim:

TYPICAL MALFUNCTION THRESHOLDS

WIRING DIAGRAM

Refer to DTC P2195 .

INSPECTION PROCEDURE

HINT:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F sensor function
provided in the Active Test. The Control the Injection Volume for A/F sensor function can help to determine
whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are
malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F sensor operation
using the Techstream.

1. Connect the Techstream to the DLC3.

2. Start the engine and turn the Techstream ON.

3. Warm up the engine at an engine speed of 2500 RPM for approximately 90 seconds.

Monitor runs whenever following DTCs not
present

Sensor 1)
P0102 - P0103 (MAF meter)
P0115 - P0118 (ECT sensor)
P0120 - P0223, P2135 (TP sensor)
P0125 (Insufficient ECT for closed loop)
P0335 (CKP sensor)
P0340 (VVT sensor)
P0351 - P0356 (Igniter)
P0500 (VSS)

Fuel system status

Closed-loop

Battery voltage

11 V or more

Either of following conditions 1 or 2 set

-

1. Engine RPM

Below 1100 RPM

2. Intake air amount per revolution

0.22 g/rev or more

Catalyst monitor

No executed

Purge-cut

Executing

Either of following conditions 1 or 2 met

-

1. Average between short-term fuel trim and long-term fuel trim

35% or more (varies with ECT)

2. Average between short-term fuel trim and long-term fuel trim

-35% or less (varies with ECT)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

4. Enter the following menus: Powertrain/Engine and ECT/Active Test/Control the Injection Volume for

A/F sensor.

5. Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT

button to change the fuel injection volume.)

6. Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and

O2S B2 S2) displayed on the Techstream.

HINT:



The Control the Injection Volume for A/F sensor operation lowers the fuel injection volume by 12.5% or
increases the injection volume by 25%.



Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

VOLTAGE REFERENCE

VOLTAGE REFERENCE

Tester Display (Sensor)

Injection Volume

Status

Voltage

AFS B1 S1 or AFS B2 S1 (A/F)

+25%

Rich

Less than 3.0 V

AFS B1 S1 or AFS B2 S1 (A/F)

-12.5%

Lean

More than 3.35 V

O2S B1 S2 or O2S B2 S2 (HO2)

+25%

Rich

More than 0.55 V

O2S B1 S2 or O2S B2 S2 (HO2)

-12.5%

Lean

Less than 0.4 V

NOTE:

The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the
Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20
seconds.

Case

A/F Sensor (Sensor 1) Output

Voltage

HO2 Sensor (Sensor 2)

Output Voltage

Main Suspected Trouble Area

1

-

2



A/F sensor



A/F sensor heater



A/F sensor circuit

3



HO2 sensor



HO2 sensor heater



HO2 sensor circuit

4



Injector



Fuel pressure



Gas leakage from exhaust
system (Air-fuel ratio

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra



Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and
graph the voltage outputs of both the A/F and HO2 sensors.



To display the graph, enter the following menus: Powertrain/Engine and ECT/Active Test/Control the
Injection Volume for A/F Sensor/A/F Control System/AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S
B2 S2.

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.



A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would
cause the engine to run rich.



A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would
cause the engine to run lean.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0171, P0172, P0174 OR P0175)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch ON and turn the Techstream ON.

c. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

d. Read the DTCs.

Result

RESULT CHART

HINT:

If any DTCs other than P0171, P0172, P0174 or P0175 are output, troubleshoot those DTCs first.

B : GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A : Go to next step

2. CHECK PCV HOSE CONNECTIONS

OK: PCV hose is connected correctly and is not damaged.

NG : REPAIR OR REPLACE PCV HOSE

extremely rich or lean)

Display (DTC Output)

Proceed To

P0171, P0172, P0174 or P0175

A

P0171, P0172, P0174 or P0175 and other DTCs

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra