Toyota Tundra. Manual — part 1173

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.

1. READ VALUE USING TECHSTREAM (THROTTLE POSITION SENSOR)

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/Data List/ETCS/Throttle Position No.1

and Throttle Position No.2.

d. Check the values displayed on the Techstream.

Result

RESULT CHART

HINT:

TP#1 stands for Throttle Position No.1, and TP#2 stands for Throttle Position No.2.

B : Go to step 5

A : Go to next step

2. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

a. Disconnect the D9 throttle body connector.

b. Disconnect the D74 ECM connector.

c. Measure the resistance according to the value(s) in the table below.

Standard resistance (Check for open)

TESTER CONNECTION SPECIFIED CONDITION

Throttle

Position No.1

Throttle

Position No.2

Throttle

Position No.1

Throttle

Position No.2

Trouble Area

Proceed

To

When Accelerator Pedal

Released

When Accelerator Pedal

Depressed

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

VC circuit open

A

4.5 to 5.0 V

4.5 to 5.0 V

4.5 to 5.0 V

4.5 to 5.0 V

E2 circuit open

0 to 0.2 V, or

4.5 to 5.0 V

2.1 to 3.1 V

(Fail-safe)

0 to 0.2 V, or

4.5 to 5.0 V

2.1 to 3.1 V

(Fail-safe)

VTA1 circuit open

or ground short

0.5 to 1.1 V

(Fail-safe)

0 to 0.2 V, or

4.5 to 5.0 V

0.5 to 1.1 V

(Fail-safe)

0 to 0.2 V, or

4.5 to 5.0 V

VTA2 circuit open

or ground short

0.5 to 1.1 V

2.1 to 3.1 V

3.2 to 4.8 V

(Not fail-safe)

4.5 to 5.0 V

(Not fail-safe)

TP sensor circuit

normal

B

Tester Connection

Condition Specified Condition

D9-5 (VC) - D74-80 (VCTA)

Always

Below 1 ohms

2008 Toyota Tundra

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

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig. 76: Identifying D9 Throttle Body & D74 Connector Terminals

OK : Go to next step

3. INSPECT ECM (VC VOLTAGE)

a. Disconnect the D9 throttle body connector.

b. Turn the ignition switch ON.

c. Measure the voltage according to the value(s) in the table below.

Standard voltage

D9-6 (VTA) - D74-78 (VTA1)

Always

Below 1 ohms

D9-4 (VTA2) - D74-77 (VTA2) Always

Below 1 ohms

D9-3 (E2) - D74-79 (ETA)

Always

Below 1 ohms

Tester Connection

Condition Specified Condition

D9-5 (VC) or D74-80 (VCTA) - Body ground

Always

10 kohms or higher

D9-6 (VTA) or D74-78 (VTA1) - Body ground

Always

10 kohms or higher

D9-4 (VTA2) or D74-77 (VTA2) - Body ground Always

10 kohms or higher

2008 Toyota Tundra

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

TESTER CONNECTION SPECIFIED CONDITION

NG : REPLACE ECM (See REMOVAL )

Fig. 77: Identifying D9 Throttle Body Connector Terminals

OK : Go to next step

4. REPLACE THROTTLE BODY ASSEMBLY

a. Replace the throttle body assembly (See REMOVAL ).

5. CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)

a. Connect the Techstream to the DLC3.

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

c. Clear DTCs (See DTC CHECK/CLEAR ).

d. Start the engine.

e. Allow the engine to idle for 15 seconds or more.

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

g. Read DTCs.

Result

RESULT CHART

B : SYSTEM OK

A : REPLACE ECM (See REMOVAL )

DTC P0121 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT
RANGE/PERFORMANCE PROBLEM

Tester Connection

Condition

Specified Condition

D9-5 (VC) - D9-3 (E2) Ignition switch ON

4.5 to 5.5 V

Display (DTC Output)

Proceed To

P0120, P0122, P0123, P0220, P0222, P0223 and/or P2135

A

No output

B

2008 Toyota Tundra

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

DESCRIPTION

Refer to DTC P0120 .

DTC TROUBLE DETECTION CONDITION CHART

MONITOR DESCRIPTION

The ECM uses the TP sensor to monitor the throttle valve opening angle.

This sensor transmits two signals: VTA1 and VTA2. VTA1 is used to detect the throttle opening angle and
VTA2 is used to detect malfunctions in VTA1. The ECM performs several checks to confirm the proper
operation of the TP sensor and VTA1.

For each throttle opening angle, a specific voltage difference is expected between the outputs of VTA1 and
VTA2. If the output voltage difference between the two signals deviates from the normal operating range, the
ECM interprets this as a malfunction of the TP sensor. The ECM illuminates the MIL and sets the DTC.

If the malfunction is not repaired successfully, the DTC is set 2 seconds after the engine is next started.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

DTC

No.

DTC Detection Condition

Trouble Area

P0121

Difference between VTA1 and VTA2 voltages less than 0.8 V, or more
than 1.6 V for 2 seconds (1 trip detection logic)

TP sensor (built into
throttle body)

Related DTCs

P0121: TP sensor rationality

Required Sensors/Components (Main)

TP sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

Within 2 seconds

MIL Operation

Immediate

Sequence of Operation

None

Either of following conditions A or B set

-

A. Ignition switch

ON

B. Electric throttle motor power

ON

TP sensor malfunction (P0120, P0122, P0123, P0220, P0223, P2135)

Not detected

2008 Toyota Tundra

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