P2123
3MZ-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
HINT:
- This Electronic Throttle Control System (ETCS) does not use a throttle cable.
- This accelerator pedal position sensor is a non-contact type.
The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position 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 V and 5 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 motor based on these signals.
HINT: After confirming DTCs P2120, P2122, P2123, P2125, P2127, P2128 and P2138, use Techstream or the OBD II scan tool to confirm the accelerator pedal position sensor output voltage.
A071015
MONITOR DESCRIPTION
When VPA or VPA2 deviates from the standard, or the difference between the voltage outputs of the two sensors is less than the threshold, the ECM concludes that there is a defect in the accelerator pedal position sensor. The ECM turns on the MIL and a DTC is set.
Example:
The voltage output of the VPA is below 0.4 V or exceeds 4.8 V.
FAIL-SAFE
The accelerator pedal position 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 switches to fail-safe mode. In fail-safe mode, the functioning 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.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P2120:
P2122:
P2123:
P2125:
P2127:
P2128:
P2138:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Read freeze frame data using Techstream or the OBD II scan tool. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.
PROCEDURE
1. READ VALUE OF TECHSTREAM (ACCEL POS #1 AND ACCEL POS #2)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch to the ON position.
(c) On Techstream, enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / Accelerator Position No. 1 and Accelerator Position No. 2. Read the values.
Standard voltage:
OK -- READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)
NG -- Continue to next step.
2. INSPECT ACCELERATOR PEDAL ASSEMBLY (ACCELERATOR PEDAL POSITION SENSOR)
(a) Disconnect the accelerator pedal position sensor connector.
(b) Measure the resistance of the sensor terminals.
Standard resistance:
NG -- REPLACE ACCELERATOR PEDAL ASSEMBLY
OK -- Continue to next step.
3. CHECK ECM (VCPA AND VCP2 VOLTAGE)
(a) Turn the ignition switch to the ON position.
(b) Measure the voltage of the ECM connector.
Standard voltage:
NG -- REPLACE ECM
OK -- Continue to next step.
4. CHECK ECM (VPA AND VPA2 VOLTAGE)
(a) Turn the ignition switch to the ON position.
(b) Measure the voltage of the ECM connector.
Standard voltage:
OK -- REPLACE ECM
NG -- Continue to next step.
5. CHECK WIRE HARNESS (ACCELERATOR PEDAL POSITION SENSOR - ECM)
(a) Disconnect the accelerator pedal position sensor connector.
(b) Disconnect the ECM connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:
Check for open
Check for short
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. READ OUTPUT DTC (ACCELERATOR PEDAL POSITION SENSOR DTCS ARE OUTPUT AGAIN)
(a) Clear the DTC (DTC Check / Clear).
(b) Start the engine.
(c) Run the engine at idle for 15 seconds or more.
(d) Read the DTC.
Result:
B -- SYSTEM OK
A -- REPLACE ECM