P0123
4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0120: Throttle / Pedal Position Sensor / Switch "A" Circuit Malfunction
DTC P0120 - Throttle / Pedal Position Sensor / Switch "A" Circuit Malfunction
DTC P0122 - Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input
DTC P0123 - Throttle / Pedal Position Sensor / Switch "A" Circuit High Input
DTC P0220 - Throttle / Pedal Position Sensor / Switch "B" Circuit
DTC P0222 - Throttle / Pedal Position Sensor / Switch "B" Circuit Low Input
DTC P0223 - Throttle / Pedal Position Sensor / Switch "B" Circuit High Input
DTC P2135 - Throttle / Pedal Position Sensor / Switch "A" / "B" Voltage Correlation
DESCRIPTION
HINT:
This ETCS (Electrical Throttle Control System) does not use a throttle cable.
The Throttle Position (TP) sensor is mounted on the throttle body, and detects the opening angle of the throttle valve. This sensor is a non-contact type, and 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 TP sensor has two sensor circuits which each transmits a signal, VTA1 and VTA2. 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 VTA 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:
- When any of these DTCs are set, check the throttle valve opening angle by entering the following menus on Techstream: Powertrain / Engine and ECT / Data List / ETCS / Throttle Sensor Volt % and Throttle Position No. 2.
- Throttle Sensor Volt % denotes the VTA1 signal (expressed in percentages), and Throttle Position No. 2 denotes the VTA2 signal (expressed in voltages).
Reference (Normal Condition):
MONITOR DESCRIPTION
The ECM uses the Throttle Position (TP) sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm the proper operation of the TP sensor.
- A specific voltage difference is expected between the sensor terminals, VTA1 and VTA2, for each throttle valve opening angle. If the difference between VTA1 and VTA2 is incorrect, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
- VTA1 and VTA2 each have a specific voltage range. If VTA1 or VTA2 is outside the normal operating range, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
- VTA1 and VTA2 should never be close to the same voltage level. If VTA1 is within 0.02 V of VTA2, the ECM determines that there is a short circuit in the sensor, and sets a DTC.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0120:
P0122:
P0123:
P0220:
P0222:
P0223:
P2135:
COMPONENT OPERATING RANGE
FAIL-SAFE
When any of these DTCs, as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions, are set, the ECM enters fail-safe mode. During the ECM cuts the current to the throttle actuator off, 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 at a minimal speed. If the accelerator pedal is depressed firmly and gently, the vehicle can be driven slowly.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
- If other DTCs relating to different systems that have terminal E3 as the ground terminal are output simultaneously, terminal E3 may have an open circuit.
- Read freeze frame data using 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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction Freeze Frame Data.
- These DTCs relate to the Throttle Position (TP) sensor.
PROCEDURE
1. READ VALUE USING TECHSTREAM
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn Techstream on.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / Throttle Sensor Volt % and Throttle Position No. 2.
(d) Check the values displayed on the tester.
Result:
HINT:
- AP denotes Accelerator Pedal.
- VTA1 is expressed as percentages, and VTA2 is expressed as voltages.
B -- CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)
A -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)
(a) Disconnect the E17 throttle body connector.
(b) Disconnect the E5 and E3 ECM connectors.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the throttle body connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
3. INSPECT ECM (VC VOLTAGE)
(a) Disconnect the E17 throttle body connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Reconnect the throttle body connector.
NG -- REPLACE ECM
OK -- Continue to next step.
4. REPLACE THROTTLE BODY
NEXT -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) and turn the tester on.
(c) Clear DTCs 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:
B -- END
A -- REPLACE ECM