malfunctions, is 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 6° 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 running 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. 187: 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
TESTER CONNECTION SPECIFIED CONDITION
Tester Connection Condition Specified Condition
2 (M+) - 1 (M-)
20°C (68°F)
0.3 to 100 ohms
2008 Toyota Tundra
2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra