DESCRIPTION The throttle position sensor is built into the throttle body with motor assembly and detects the opening angle of the throttle valve. This sensor is a non-contact type sensor. It uses Hall-effect elements in order to yield accurate signals even in extreme driving conditions, such as at high speeds as well as very low speeds. The throttle position sensor has 2 sensor circuits, VTA1 and VTA2, each of which transmits a signal. VTA1 is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA1. The sensor signal voltages vary between 0 V and 5 V in proportion to the throttle valve opening angle, and are transmitted to the VTA1 and VTA2 terminals of the ECM. As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage increases. The ECM calculates the throttle valve opening angle according to these signals and controls the throttle actuator in response to driver inputs. These signals are also used in calculations such as air fuel ratio correction, power increase correction and fuel-cut control. ![]() HINT:
MONITOR DESCRIPTION The ECM uses the throttle position sensor to monitor the throttle valve opening angle. If the VTA1 terminal voltage is less than the threshold, the ECM will illuminate the MIL and store this DTC. MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
CONFIRMATION DRIVING PATTERN HINT:
![]()
FAIL-SAFE When this DTC is stored, 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 valve opening 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 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 engine switch is turned off. WIRING DIAGRAM ![]() CAUTION / NOTICE / HINT 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
(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 / Throttle Position Sensor No.1 Voltage. Powertrain > Engine > Data List
(e) Read the values displayed on the Techstream. (f) Disconnect the throttle body with motor assembly connector. (g) Compare the value of the Data List item Throttle Position Sensor No.1 Voltage after disconnecting the throttle body with motor assembly connector to the value when the connector was connected.
HINT: Perform "Inspection After Repair" after replacing the throttle body with motor assembly. Click here
(a) Disconnect the throttle body with motor assembly connector. (b) Disconnect the ECM connector. (c) Measure the resistance according to the value(s) in the table below. Standard Resistance:
|
Toyota Avalon Service & Repair Manual > Dynamic Radar Cruise Control System(for Gasoline Model): Brake Switch "A" Circuit Open (P057113)
DESCRIPTION When the brakes are applied by the dynamic radar cruise control system, the skid control ECU (brake actuator assembly) operates the stop light switch assembly (stop light control relay) to illuminate the stop lights. If the ECM receives a stop light control relay malfunction signal from ...