P0120

2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P0120-P0123,P0220,P0222,P0223,P2135: Throttle / Pedal Position Sensor / Switch "A" Circuit Malfunction

DESCRIPTION

HINT
- These DTCs relate to the throttle position sensor.
The throttle position sensor is mounted on the throttle body assembly, and detects the opening angle of the throttle valve. This sensor is a non-contact type. It uses Hall-effect elements in order to yield accurate signals even in extreme conditions.

The throttle position sensor has 2 sensor circuits, each of which transmits a signal, VTA and VTA2. VTA is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA. 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 hybrid vehicle control ECU.

As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage increases. The hybrid vehicle control ECU 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 enrichment correction and fuel-cut control.









MONITOR DESCRIPTION

P0120, P0122, P0123, P0220, P0222, P0223, P2135

The hybrid vehicle control ECU uses the throttle position sensor to monitor the throttle valve opening angle. There are several checks that the hybrid vehicle control ECU performs to confirm the proper operation of the throttle position sensor.

- A specific voltage difference is expected between the sensor terminals, VTA and VTA2, for each throttle valve opening angle. If the difference between VTA and VTA2 is incorrect, the hybrid vehicle control ECU interprets this as a malfunction in the sensor circuit, and sets a DTC.

- VTA and VTA2 each have a specific voltage range. If VTA or VTA2 is outside the normal operating range, the hybrid vehicle control ECU interprets this as a malfunction in the sensor circuit, and sets a DTC.

- VTA and VTA2 should never be close to the same voltage level. If VTA is within 0.02 V of VTA2, the hybrid vehicle control ECU determines that there is a short circuit in the sensor circuit, and sets a DTC.

If the malfunction is not repaired successfully, a DTC is set 10 seconds after the engine is next started.

P0121

For each throttle opening angle, a specific voltage difference is expected between the outputs of VTA and VTA2. If the output voltage difference between the two signals deviates from the normal operating range, the hybrid vehicle control ECU interprets this as a malfunction in the throttle position sensor. The hybrid vehicle control ECU illuminates the MIL and stores the DTC.

This sensor transmits two signals: VTA and VTA2. VTA is used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA. The hybrid vehicle control ECU performs several checks to confirm the proper operation of the throttle position sensor and VTA.

If the malfunction is not repaired successfully, the DTC is stored 2 seconds after the engine is next started.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

P0120, P0122, P0123, P0220, P0222, P0223, P2135





P0121





TYPICAL MALFUNCTION THRESHOLDS

P0120





P0121





P0122





P0123





P0220





P0222





P0223





P2135 Case 1





P2135 Case 2





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





- Connect the Techstream to the DLC3.

- Turn the power switch on (IG) and turn the Techstream on.

- Clear the DTCs DTC Check / Clear.

- Turn the power switch off and wait for at least 30 seconds.

- Turn the power switch on (IG) and turn the Techstream on [A].

- Put the engine in inspection mode Component Tests and General Diagnostics.

- Start the engine.

- With the vehicle stationary, fully depress and release the accelerator pedal [B].

- Idle the engine for 2 seconds or more [C].

- Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

- Read the DTC [D].

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
- Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

- Input the DTC: P0120, P0121, P0122, P0123, P0220, P0222, P0223 or P2135.

- Check the DTC judgment result.





HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [C] again.
FAIL-SAFE

When any of these DTCs, as well as other DTCs relating to electronic throttle control system malfunctions, are set, the hybrid vehicle control ECU enters fail-safe mode. During fail-safe mode, the hybrid vehicle control ECU cuts the current to the throttle actuator, and the throttle valve is returned to a 6.5° throttle angle by the return spring. The hybrid vehicle control ECU stops the engine and the vehicle can be driven using solely the hybrid system. 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 power switch is then turned off.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
- DTC P0121 is stored when the voltages output from VTA 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 VTA + 1.11 V

VTA: Throttle Position No. 1

VTA2: Throttle position No. 2

- Read freeze frame data using the Techstream. The hybrid vehicle control ECU 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.
PROCEDURE

1. CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - HYBRID VEHICLE CONTROL ECU)

(a) Disconnect the throttle body assembly connector.

(b) Disconnect the hybrid vehicle control ECU connector.

(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 assembly connector.

(e) Reconnect the hybrid vehicle control ECU connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. INSPECT HYBRID VEHICLE CONTROL ECU (VC VOLTAGE)

(a) Disconnect the throttle body assembly connector.





(b) Turn the power switch on (IG).

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





(d) Reconnect the throttle body assembly connector.

NG -- REPLACE HYBRID VEHICLE CONTROL ECU Removal
OK -- Continue to next step.

3. REPLACE THROTTLE BODY ASSEMBLY

(a) Replace the throttle body assembly Removal.

NEXT -- Continue to next step.

4. CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs DTC Check / Clear.

(e) Put the engine in inspection mode Component Tests and General Diagnostics.

(f) Start the engine.

(g) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(h) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(i) Read the DTCs.

Result:





B -- END

A -- REPLACE HYBRID VEHICLE CONTROL ECU Removal