P2127
DTC P2127 Throttle/Pedal Position Sensor/Switch "E" Circuit Low InputHINT: These DTCs relate to the accelerator pedal position sensor.
CIRCUIT DESCRIPTION
DTC Detection Condition:
The accelerator pedal position sensor is mounted on the throttle body and it has the 2 sensors to detect the accelerator pedal position and a malfunction of the accelerator pedal position sensor.
In the accelerator pedal position sensor, the voltage applied to the terminals VPA and VPA2 of the ECM changes between 0 V to 5 V, in proportion to the opening angle of the accelerator pedal. The VPA is a signal to indicate the actual accelerator pedal opening angle which is used for the engine control, and the VPA2 is a signal to indicate the information about the opening angle which is used for detecting a malfunction.The ECM judges the current opening angle of the accelerator pedal from these signals input from terminals VPA and VPA2, and the ECM controls the throttle motor based on these signals.
If this DTCs is stored, the throttle valve is locked at a certain opening angle. Also, the whole electronically controlled throttle operation is cancelled until the system returns to normal and the ignition switch is turned OFF.
HINT: After confirming DTC P2120, P2122, P2123, P2125, P2127, P2128 and P2138 use the OBD II scan tool or the hand-held tester to confirm the throttle valve opening percentage.
HINT:
- Accelerator pedal position is expressed as voltages.
- AP stands for Accelerator Pedal.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Conditions:
Typical Malfunction Thresholds:
Component Operating Range:
When either of the voltage outputs of VPA or VPA2 deviates from the standard range, or the difference between the voltage outputs of the two sensors is exceeds the threshold, the ECM determines that there a defect in the accelerator pedal position sensor. The ECM illuminates the MIL and sets a DTC.
Example:
When the voltage output of the VPA drops below 0.2 V or exceeds 4.7 V.
Wiring Diagram:
INSPECTION PROCEDURE
HINT: Read freeze frame data using the hand-held tester or the OBD II scan tool. 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.
Step 1:
Step 2 - 4:
Step 5 - 6:
Hand-held tester:
Step 1 - 3:
Step 4 - 5:
OBD II scan tool (excluding hand-held tester):
CHECK FOR INTERMITTENT PROBLEMS
HINT:
Hand-held tester only:
Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1trip detection logic, which is more sensitive to malfunctions than normal mode (default) that uses 2trip detection logic.
a. Clear DTCs.
b. Switch the ECM from normal mode to check mode using a hand-held tester.
c. Perform a simulation test.
d. Check and wiggle the harness(es), the connector(s) and terminal(s).