SFI SYSTEM, Diagnostic DTC:P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135

DESCRIPTION

The throttle position sensor is mounted on the throttle body, 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, 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 enrichment correction and fuel-cut control.

MONITOR DESCRIPTION

The ECM uses the throttle position sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm that the throttle position sensor is operating properly.

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

• 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 stores 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 stores 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 stores a DTC.

P0121

• This sensor transmits two signals: VTA1 and VTA2. VTA1 is used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA1. The ECM performs several checks to confirm that the throttle position sensor and VTA1 are operating properly.

  For each throttle opening angle, a specific voltage difference is expected between the outputs of VTA1 and VTA2. If the output voltage difference between the two signals deviates from the normal operating range, the ECM interprets this as a malfunction of the throttle position sensor. The ECM illuminates the MIL and stores the DTC.

CONFIRMATION DRIVING PATTERN

1. Connect the intelligent tester to the DLC3.

2. Turn the ignition switch to ON and turn the intelligent tester on.

3. Clear the 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 intelligent tester on [A].

6. Start the engine.

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

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

9. Enter the following menus: Powertrain / Engine and ECT / DTC [D].

10. Read the pending DTCs.

    Tech Tips

    
    

    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

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

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

13. Check the DTC judgment result.

    Intelligent tester Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
    UNKNOWN	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips

    
    

    • 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] through [D] again.

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 5.5° 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 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 ignition switch is then turned off.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

• These DTCs relate to the throttle position sensor.

• Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions 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 INTELLIGENT TESTER (THROTTLE POSITION SENSOR)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

   4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Throttle Position No. 1 and Throttle Position No. 2.

   5. Read the values displayed on the tester.

      Result

      When Accelerator Pedal Released When Accelerator Pedal Depressed Trouble Area Proceed to Throttle Position No.1 Throttle Position No.2 Throttle Position No.1 Throttle Position No.2 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V 0 to 0.2 V VC circuit open A 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V 4.5 to 5.0 V E2 circuit open 0 to 0.2 V, or 4.5 to 5.0 V 2.1 to 3.1 V (Fail-safe) 0 to 0.2 V, or 4.5 to 5.0 V 2.1 to 3.1 V (Fail-safe) VTA1 circuit open or ground short 0.6 to 1.4 V (Fail-safe) 0 to 0.2 V, or 4.5 to 5.0 V 0.6 to 1.4 V (Fail-safe) 0 to 0.2 V, or 4.5 to 5.0 V VTA2 circuit open or ground short 0.5 to 1.1 V 2.1 to 3.1 V 3.2 to 4.8 V (Not fail-safe) 4.6 to 5.0 V (Not fail-safe) Throttle position sensor circuit normal B

      Tech Tips

      
      

      • 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
        VTA1: Throttle Position No. 1
        VTA2: Throttle position No. 2

      • If DTC P0121 is output, proceed to the "CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)".

   
   

   B

   CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS) Click here

   A

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

   
   

   1. Disconnect the throttle with motor body assembly connector.

   2. Disconnect the ECM connector.

   3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      for RHD Tester Connection Condition Specified Condition B29-5 (VC) - B23-115 (VCTA) Always Below 1 Ω B29-6 (VTA) - B23-84 (VTA1) Always Below 1 Ω B29-4 (VTA2) - B23-83 (VTA2) Always Below 1 Ω B29-3 (E2) - B23-116 (ETA) Always Below 1 Ω
      for LHD Tester Connection Condition Specified Condition B29-5 (VC) - B22-115 (VCTA) Always Below 1 Ω B29-6 (VTA) - B22-84 (VTA1) Always Below 1 Ω B29-4 (VTA2) - B22-83 (VTA2) Always Below 1 Ω B29-3 (E2) - B22-116 (ETA) Always Below 1 Ω

      Standard Resistance (Check for Short)
      for RHD Tester Connection Condition Specified Condition B29-5 (VC) or B23-115 (VCTA) - Body ground Always 10 kΩ or higher B29-6 (VTA) or B23-84 (VTA1) - Body ground Always 10 kΩ or higher B29-4 (VTA2) or B23-83 (VTA2) - Body ground Always 10 kΩ or higher
      for LHD Tester Connection Condition Specified Condition B29-5 (VC) or B22-115 (VCTA) - Body ground Always 10 kΩ or higher B29-6 (VTA) or B22-84 (VTA1) - Body ground Always 10 kΩ or higher B29-4 (VTA2) or B22-83 (VTA2) - Body ground Always 10 kΩ or higher

   4. Reconnect the throttle with motor body assembly connector.

   5. Reconnect the ECM connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR (THROTTLE POSITION SENSOR - ECM)

   OK

3. INSPECT ECM (VC VOLTAGE)

   
   
   1. 

      Text in Illustration

      *a	Front view of wire harness connector (to Throttle with Motor Body Assembly)

      Disconnect the throttle with motor body assembly connector.

   2. Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition B29-5 (VC) - B29-3 (E2) Ignition switch ON 4.5 to 5.5 V

   4. Reconnect the throttle with motor body assembly connector.

   
   

   NG

   REPLACE ECM Click here

   OK

4. REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY

   
   

   1. Replace the throttle with motor body assembly Click here.

      Tech Tips

      Perform "Inspection After Repairs" after replacing the throttle with motor body assembly Click here.

   
   

   NEXT

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

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

   4. Clear DTCs Click here.

   5. Start the engine.

   6. Allow the engine to idle for 15 seconds or more.

   7. Enter the following menus: Powertrain / Engine and ECT / DTC.

   8. Read the DTCs.

      Result
      Result Proceed to DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and/or P2135 is output A DTC is not output B

   
   

   A

   REPLACE ECM Click here

   B

   END