FAIL-SAFE
When any of these DTCs, as well as other DTCs relating to 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 6锟斤拷 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 engine switch is then turned off.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data
the moment a DTC is stored. 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.
PROCEDURE
1. READ VALUE USING TECHSTREAM (THROTTLE POSITION SENSOR)
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine / Data List / ETCS / Throttle Position No. 1 and Throttle Position No. 2.
(e) Read the values displayed on the Techstream.
Result
HINT
- DTC P0121 is stored when the voltages output from VTA1 and VTA2 are not consistent with the characteristics of the sensors.
Therefore, check the Freeze Frame Data when this DTC is output. Use the following formula to confirm relative fluctuations
in voltage.
Features of sensor output:
VTA2 x 0.8 is approximately equal to VTA1 + 1.11 V
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