P0121

P0121 ACCELERATOR PEDAL POSITION (APP) SENSOR




COMPONENT DESCRIPTION
Electric Throttle Control Actuator consists of throttle control motor, acceleration pedal position sensor, throttle position sensor, etc.

Accelerator pedal position sensor is connected to the accelerator pedal through the throttle drum and accelerator wire, and detects the accelerator pedal position by the throttle drum rotation angle.

Accelerator pedal position sensor has the two sensors. These sensors are a kind of potentiometers which transform the accelerator pedal position into output voltage, and emit the voltage signal to the ECM. In addition, these sensors detect the opening and closing speed of the accelerator pedal and feed the voltage signals to the ECM. The ECM judges the current opening angle of the accelerator pedal from these signals and controls the throttle control motor based on these signals.

Idle position of the accelerator pedal is determined by the ECM receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine operation such as fuel cut.

Consult-II Reference Value In Data Monitor Mode:

On Board Diagnosis Logic
Malfunction is detected when
(Malfunction A) an excessively low or high voltage from the accelerator pedal position sensor 1 is sent to ECM,
(Malfunction B) an excessively low or high voltage from the accelerator pedal position sensor 2 is sent to ECM,
(Malfunction C) a difference between signals from sensor 1 and sensor 2 is out of the specified range.

Fail-Safe Mode:

Possible Cause
- Harness or connectors
(The accelerator pedal position sensor 1 or 2 circuit is open or shorted.)
- Electric throttle control actuator

DTC Confirmation Procedure

NOTE:
- If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.

TESTING CONDITION: Before performing the following procedure, confirm that battery voltage is more than 10 V at idle.




With CONSULT-II
1. Turn ignition switch "ON".
2. Select "DATA MONITOR" mode with CONSULT-II.
3. Start engine and let it idle for 1 second.
4. If 1st trip DTC is detected, go to "Diagnostic Procedure".

With GST
Follow the procedure "With CONSULT-II" above.

EC-APPS-01:

Wiring Diagram

Step 1:

Step 2 - 4:

Step 5 - 9:

Diagnostic Procedure

Component Inspection

ACCELERATOR PEDAL POSITION SENSOR
1. Reconnect all harness connectors disconnected.
2. Perform "Throttle Valve Closed Position Learning".
3. Turn ignition switch "ON".
4. Set selector lever to "D" position.







5. Check voltage between ECM terminals 87 (APP sensor 1 signal), 117 (APP sensor 2 signal) and engine ground under the following conditions.
6. If NG, replace electric throttle control actuator and go to the next step.
7. Perform "Throttle Valve Closed Position Learning".
8. Perform "Idle Air Volume Learning".
Remove and Installation

ELECTRIC THROTTLE CONTROL ACTUATOR
Refer to "INTAKE MANIFOLD".