SFI SYSTEM, Diagnostic DTC:P2120, P2122, P2123, P2125, P2127, P2128, P2138
| DTC Code | DTC Name |
|---|---|
| P2120 | Throttle / Pedal Position Sensor / Switch "D" Circuit |
| P2122 | Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input |
| P2123 | Throttle / Pedal Position Sensor / Switch "D" Circuit High Input |
| P2125 | Throttle / Pedal Position Sensor / Switch "E" Circuit |
| P2127 | Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input |
| P2128 | Throttle / Pedal Position Sensor / Switch "E" Circuit High Input |
| P2138 | Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation |
DESCRIPTION
Tech Tips
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This electronic throttle control system does not use a throttle cable.
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These DTCs relate to the accelerator pedal position sensor.
The accelerator pedal position 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 conditions. The voltage from this sensor, which is applied to terminals VPA and VPA2 of the ECM, varies between 0.5 V and 4.75 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal operating 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 accelerator pedal position 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.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2120 | VPA fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic) |
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| P2122 | VPA is 0.4 V or less for 0.5 seconds or more when accelerator pedal depressed (1 trip detection logic) |
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| P2123 | VPA is 4.8 V or more for 2.0 seconds or more (1 trip detection logic) |
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| P2125 | VPA2 fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic) |
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| P2127 | VPA2 is 1.2 V or less for 0.5 seconds or more when accelerator pedal depressed (1 trip detection logic) |
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| P2128 | Conditions (a) and (b) continue for 2.0 seconds or more (1 trip detection logic): (a) VPA2 is 4.8 V or more (b) VPA is between 0.4 V and 3.45 V |
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| P2138 | Condition (a) or (b) continues for 2.0 seconds or more (1 trip detection logic): (a) Difference between VPA and VPA2 is 0.02 V or less (b) VPA is 0.4 V or less and VPA2 is 1.2 V or less |
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Tech Tips
When any of these DTCs are set, check the accelerator pedal position sensor voltage by entering the following menus using the intelligent tester: Powertrain / Engine / Data List / All Data / Accel Sensor Out No.1 and Accel Sensor Out No.2.
| Trouble Area | Accel Sensor Out No. 1 When Accelerator Pedal Fully Released |
Accel Sensor Out No. 2 When Accelerator Pedal Fully Released |
Accel Sensor Out No. 1 When Accelerator Pedal Fully Depressed |
Accel Sensor Out No. 2 When Accelerator Pedal Fully Depressed |
|---|---|---|---|---|
| VCP circuit open | 0 to 0.4 V | 0 to 0.4 V | 0 to 0.4 V | 0 to 0.4 V |
| Open or ground short in VPA circuit | 0 to 0.4 V | 1.2 to 2.0 V | 0 to 0.4 V | 3.4 to 4.75 V |
| Open or ground short in VPA2 circuit | 0.5 to 1.1 V | 0 to 0.4 V | 2.5 to 4.5 V | 0 to 0.4 V |
| EPA circuit open | 4.5 to 4.98 V | 4.5 to 4.98 V | 4.5 to 4.98 V | 4.5 to 4.98 V |
| Normal condition | 0.5 to 1.1 V | 1.2 to 2.0 V | 2.6 to 4.5 V | 3.4 to 4.75 V |
Tech Tips
Accelerator pedal positions are expressed as voltages.
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 engine switch is then turned off.
WIRING DIAGRAM
INSPECTION PROCEDURE
Tech Tips
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These DTCs relate to the accelerator pedal position sensor.
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Read freeze frame data using the intelligent tester. 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.
PROCEDURE
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READ VALUE USING INTELLIGENT TESTER (ACCELERATOR POSITION SENSOR)
Text in Illustration *a Fully Depressed *b Fully Released
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Connect the intelligent tester to the DLC3.
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Turn the engine switch on (IG).
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Turn the tester on.
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Enter the following menus: Powertrain / Engine / Data List / All Data / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.
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Read the values displayed on the tester.
Standard Voltage Accelerator Pedal Operation Accel Sensor Out No. 1 Accel Sensor Out No. 2 Fully Released 0.5 to 1.1 V 1.2 to 2.0 V Fully Depressed 2.6 to 4.5 V 3.4 to 4.75 V
OK 
CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS) Click here
NG
CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM) Click here
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CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
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Disconnect the accelerator pedal sensor assembly connector.
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open) Tester Connection Condition Specified Condition A46-6 (VPA) - A70-55 (VPA) Always Below 1 Ω A46-5 (EPA) - A70-59 (EPA) Always Below 1 Ω A46-4 (VCPA) - A70-57 (VCPA) Always Below 1 Ω A46-3 (VPA2) - A70-56 (VPA2) Always Below 1 Ω A46-2 (EPA2) - A70-60 (EPA2) Always Below 1 Ω A46-1 (VCP2) - A70-58 (VCP2) Always Below 1 Ω Standard Resistance (Check for Short) Tester Connection Condition Specified Condition A46-6 (VPA) or A70-55 (VPA) - Body ground Always 10 kΩ or higher A46-5 (EPA) or A70-59 (EPA) - Body ground Always 10 kΩ or higher A46-4 (VCPA) or A70-57 (VCPA) - Body ground Always 10 kΩ or higher A46-3 (VPA2) or A70-56 (VPA2) - Body ground Always 10 kΩ or higher A46-2 (EPA2) or A70-60 (EPA2) - Body ground Always 10 kΩ or higher A46-1 (VCP2) or A70-58 (VCP2) - Body ground Always 10 kΩ or higher -
Reconnect the accelerator pedal sensor assembly connector.
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Reconnect the ECM connector.
NG 
REPAIR OR REPLACE HARNESS OR CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
OK 
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INSPECT ECM (VCPA AND VCP2 VOLTAGE)
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Text in Illustration *a Front view of wire harness connector
(to Accelerator Pedal Sensor Assembly)
Disconnect the accelerator pedal sensor assembly connector.
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Turn the engine switch on (IG).
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Measure the voltage according to the value(s) in the table below.
Standard Voltage Tester Connection Condition Specified Condition A46-4 (VCPA) - A46-5 (EPA) Engine switch on (IG) 4.5 to 5.5 V A46-1 (VCP2) - A46-2 (EPA2) Engine switch on (IG) 4.5 to 5.5 V -
Reconnect the accelerator pedal sensor assembly connector.
NG
REPLACE ECM Click here
OK
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REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY (ACCELERATOR PEDAL POSITION SENSOR)
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Replace the accelerator pedal sensor assembly Click here.
NEXT
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CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)
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Connect the intelligent tester to the DLC3.
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Turn the engine switch on (IG).
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Turn the tester on.
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Clear the DTCs Click here.
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Fully depress and release the accelerator pedal.
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Check that 5 seconds or more have elapsed since the engine switch was turned to on (IG).
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Enter the following menus: Powertrain / Engine / DTC.
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Read the DTCs.
Result Result Proceed to DTC P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 is output A DTC is not output B
B
END
A 
REPLACE ECM Click here
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