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Home >> Scion >> 2011 >> xD L4-1.8L (2ZR-FE) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P2128

P2128





2ZR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2120, P2122, P2123, P2125, P2127, P2128, P2138: Throttle / Pedal Position Sensor / Switch "D" Circuit


DESCRIPTION

The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). 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 voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0.5 V and 4.5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP sensor itself.

The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

HINT
- This ETCS (Electronic Throttle Control System) does not use a throttle cable.
- These DTCs relate to the Accelerator Pedal Position (APP) sensor.









HINT
When any of these DTCs are set, check the APP sensor voltage by selecting the following menu items using the Techstream: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.





HINT
Accelerator pedal positions are expressed as voltages.

MONITOR DESCRIPTION

When either output voltage of VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the APP sensor. The ECM then illuminates the MIL and sets a DTC.

Example:

When the output voltage of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is set.

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

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P2120:





P2122:





P2123:





P2125:





P2127:





P2128:





P2138:





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).

4. Turn the ignition switch off and wait for at least 30 seconds.

5. Turn the ignition switch to ON and turn the Techstream on [A].

6. Fully depress and release the accelerator pedal [B].

7. Check that 5 seconds or more have elapsed since the DTCs were cleared.

8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].

9. Read the DTCs.

HINT
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.

10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

11. Input the DTC: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.

12. Check the DTC judgment result.





HINT
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] and [C] again.

13. If the test result is INCOMPLETE or UNKNOWN and no DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, the ECM enters fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue driving. If both of the circuits malfunction, the ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine idles.

Fail-safe mode continues until a pass condition is detected, and the ignition switch is turned to OFF.

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.

PROCEDURE

1. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR)





(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

(e) Read the value displayed on the Techstream.

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

OK -- CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)

2. CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

(a) Disconnect the accelerator pedal position sensor connector.

(b) Disconnect the ECM 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 accelerator pedal position sensor connector.

(e) Reconnect the ECM connector.

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

3. INSPECT ECM (VCPA AND VCP2 VOLTAGE)





(a) Disconnect the accelerator pedal position sensor connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:





Text in Illustration





(d) Reconnect the accelerator pedal position sensor connector.

NG -- REPLACE ECM Removal
OK -- Continue to next step.

4. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

(a) Replace the accelerator pedal rod assembly Removal.

NEXT -- Continue to next step.

5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Start the engine.

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

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

(h) Read the DTCs.

Result





B -- END

A -- REPLACE ECM Removal
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