Toyota Tundra. Manual — part 1409

The throttle actuator is operated by the ECM and opens and closes the throttle valve using gears.

The opening angle of the throttle valve is detected by the Throttle Position (TP) sensor, which is mounted on the
throttle body. The TP sensor provides feedback to the ECM. This feedback allows the ECM to appropriately
control the throttle actuator and monitor the throttle opening angle as the ECM responds to driver inputs.

HINT:

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

DTC DETECTION CONDITION AND TROUBLE AREA

MONITOR DESCRIPTION

The ECM monitors the electrical current through the electronic actuator, and detects malfunctions and open
circuits in the throttle actuator based on this value. If the current is outside the standard range, the ECM
determines that there is a malfunction in the throttle actuator. In addition, if the throttle valve does not function
properly (for example, stuck on), the ECM determines that there is a malfunction. The ECM then illuminates
the MIL and sets a DTC.

Example:

When the electrical current is less than 0.5 A and the throttle actuator duty ratio exceeds 80%, the ECM
interprets this as the current being outside the standard range, and illuminates the MIL and sets a DTC. If the
malfunction is not repaired successfully, a DTC is set when the engine is quickly revved to a high RPM several
times after the engine is started and has idled for 5 seconds.

MONITOR STRATEGY

MONITOR STRATEGY

DTC

Code

DTC Detection Condition

Trouble Area

P2102

Conditions (a) and (b) continue for 2.0 seconds (1 trip
detection logic):

a. Throttle actuator duty ratio 80% or more

b. Throttle actuator current less than 0.5 A



Open in throttle actuator
circuit



Throttle actuator



ECM

P2103

Either of following conditions met (1 trip detection logic):



Hybrid IC diagnosis signal failure



Hybrid IC current limiter port failure



Short in throttle actuator
circuit



Throttle actuator



Throttle valve



Throttle body assembly



ECM

Related DTCs

P2102: Throttle actuator current (low current)
P2103: Throttle actuator current (high current)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

P2102:

TYPICAL ENABLING CONDITIONS - P2102

P2103:

TYPICAL ENABLING CONDITIONS - P2103

TYPICAL MALFUNCTION THRESHOLDS

P2102:

TYPICAL MALFUNCTION THRESHOLDS - P2102

P2103:

TYPICAL MALFUNCTION THRESHOLDS - P2103

FAIL-SAFE

Required Sensors/Components (Main)

Throttle actuator (throttle body)

Required Sensors/Components (Related)

None

Frequency of Operation

Continuous

Duration

2 seconds: P2102
Within 1 second: P2103

MIL Operation

Immediate

Sequence of Operation

None

Monitor runs whenever following DTCs not present

None

Throttle actuator

Activated

Duty-cycle ratio to open throttle actuator

80% or more

Throttle actuator power supply

8 V or higher

Throttle actuator

Activated

Throttle actuator power supply

8 V or higher

Battery voltage

8 V or higher

Starter

OFF

Throttle actuator current

Less than 0.5 A

Either of the following condition is met

Condition 1 or 2

1. Hybrid IC diagnosis signal

Fail for 25 times

2. Hybrid IC current limiter port

Fail for 0.6 seconds

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

When either of these DTCs, or other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions
are set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator,
and the throttle valve is returned to a 7° throttle angle by the return spring. The ECM then adjusts the engine
output by controlling the fuel injection (intermittent fuel-cut) and ignition timing, in accordance with the
accelerator pedal opening angle, to allow the vehicle to continue at a minimal speed. If the accelerator pedal is
depressed firmly and gently, the vehicle can be driven slowly.

Fail-safe mode continues until a pass condition is detected, and the ignition switch is then turned OFF.

WIRING DIAGRAM

Fig. 203: Throttle Actuator Control Motor Circuit - Wiring Diagram

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.



The throttle actuator current Throttle Motor Current and the throttle actuator duty ratio Throttle Motor
Open Duty/Throttle Motor Close Duty can be read using the Techstream. However, the ECM shuts off
the throttle actuator current when the ETCS malfunctions.

1. INSPECT THROTTLE BODY (RESISTANCE OF THROTTLE ACTUATOR)

a. Disconnect the D9 throttle body connector.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Fig. 204: Identifying D9 Throttle Body Connector

NG : REPLACE THROTTLE BODY ASSEMBLY (See REMOVAL )

OK : Go to Next Step

2. CHECK HARNESS AND CONNECTOR (THROTTLE ACTUATOR - 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

STANDARD RESISTANCE SPECIFICATION

Tester Connection Condition Specified Condition

2 (M+) - 1 (M-)

20°C (68°F)

0.3 to 100 ohms

Tester Connection

Condition Specified Condition

D9-2 (M+) - D74-19 (M+)

Always

Below 1 ohms

D9-1 (M-) - D74-18 (M-)

Always

Below 1 ohms

D9-2 (M+) or D74-19 (M+) - Body ground Always

10 kohms or higher

D9-1 (M-) or D74-18 (M-) - Body ground

Always

10 kohms or higher

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra