P2138
3UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2120: Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2120 - Throttle / Pedal Position Sensor / Switch "D" Circuit
DTC P2122 - Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
DTC P2123 - Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
DTC P2125 - Throttle / Pedal Position Sensor / Switch "E" Circuit
DTC P2127 - Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
DTC P2128 - Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
DTC P2138 - Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation
DESCRIPTION
A vehicle that is equipped with an Electronic Throttle Control System (ETCS) does not have a throttle cable. The APP sensor is mounted on the accelerator pedal bracket. The APP sensor has 2 sensor elements/signal outputs: VPA1 and VPA2. VPA1 is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA1. Voltage applied to VPA1 and VPA2 changes between 0.4 V and 4.8 V in proportion to the accelerator pedal angle.
The ECM monitors the accelerator pedal angle from VPA1 and VPA2 signal outputs, and controls the throttle actuator based on these signals.
HINT: After confirming DTC P2120, P2122, P2123, P2125, P2127, P2128 and P2138, use the Techstream to confirm the APP sensor output voltage.
MONITOR DESCRIPTION
When either voltage output VPA1 or VPA2 deviates from the standard range, or the difference between the voltage outputs of the two sensors is less than threshold, the ECM concludes that there is a defect in the APP sensor. The ECM illuminates the MIL and sets a DTC.
Example:
When the voltage output of the VPA1 below 0.4 V or exceeds 4.8 V.
This monitor runs for 2 seconds (the first 2 seconds of engine idle) after the engine is started (1 trip detection logic).
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P2120:
P2122:
P2123:
P2125:
P2127:
P2128:
P2138:
COMPONENT OPERATING RANGE
FAIL-SAFE
The APP sensor has 2 (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the two sensor circuits and changes to limp mode. In limp mode, the remaining circuit is used to calculate the accelerator pedal opening angle to allow the vehicle to continue driving.
If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal to be fully closed.
In this case, the throttle valve will remain closed as if the engine is idling.
If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
- Read freeze frame data using the Techstream. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.
- This is the repair procedure for the Accelerator Pedal Position (APP) sensor.
PROCEDURE
1. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION NO. 1 AND ACCELERATOR POSITION NO. 2)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.
(d) Read the Accelerator Position #1 and Accelerator Position #2 values.
Standard Voltage:
OK -- READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)
NG -- Continue to next step.
2. INSPECT ACCELERATOR PEDAL ROD ASSEMBLY (APP SENSOR)
(a) Disconnect the A14 APP sensor connector.
(b) Measure the resistance of the sensor.
Standard Resistance:
NG -- REPLACE ACCELERATOR PEDAL ROD ASSEMBLY
OK -- Continue to next step.
3. CHECK ECM (VCPA, VCP2, VOLTAGE)
(a) Turn the ignition switch ON.
(b) Measure the voltage of the ECM connector.
Standard Voltage:
NG -- REPLACE ECM
OK -- Continue to next step.
4. CHECK WIRE HARNESS (APP SENSOR - ECM)
(a) Disconnect the A14 APP sensor connector.
(b) Disconnect the E5 ECM connector.
(c) Measure the resistance of the wire harness side connectors.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE ACCELERATOR PEDAL ROD ASSEMBLY
5. READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)
(a) Clear the DTC DTC Check / Clear.
(b) Allow the engine to idle for 15 seconds.
(c) Read the DTC.
Result:
B -- CHECK FOR INTERMITTENT PROBLEM
A -- REPLACE ECM