P0123
DTC P0123 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT HIGH INPUTHINT: These DTCs relate to the Throttle Position (TP) sensor
CIRCUIT DESCRIPTION
DTC Detection Conditions:
The TP sensor is mounted on the throttle body and detects the throttle valve opening angle.
When the throttle valve is fully closed, the sensor transmits a signal voltage of approximately 0.3 to 1.0 V to terminal VTA of the ECM. This signal voltage increases in proportion to the opening angle of the throttle valve, reaching approximately 3.2 to 4.9 when the throttle valve is fully open.
The ECM determines the vehicle driving conditions from these signals and uses this information in functions such as air-fuel ratio correction, power increase correction and fuel-cut control.
HINT:
- Fail-safe mode: When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts fuel intermittently. Fail-safe mode continues until a pass condition detected and the ignition switch is turned to OFF.
- When any of these DTCs are set, check the throttle valve opening angle using a hand-held tester or OBD II scan tool.
MONITOR DESCRIPTION
Monitor Strategy:
Typical Enabling Condition:
Typical Malfunction Thresholds:
Component Operating Range:
The resistance of the Throttle Position (TP) sensor varies in accordance with the throttle valve opening angle. The ECM transmits a standardized reference voltage to the +:VC terminal of the TP sensor and calculates the throttle valve opening angle based on the voltage received from the Signal: VTA terminal of the sensor. When the throttle valve is near the fully closed position, the output voltage of the TP sensor is low. When it is near the fully open position, the output voltage is high.
If the ECM detects that the output voltage of the TP sensor is outside the normal range, the ECM interprets this as a malfunction in the TP sensor and sets a DTC.
Wiring Diagram:
INSPECTION PROCEDURE
HINT:
- If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
- Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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 - 2:
Step 3 - 4:
Step 5:
Hand-held tester
Step 1 - 2:
OBD II scan tool (excluding the 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 a hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which is more sensitive to malfunctions than normal mode (default), which uses 2 trip detection logic.
a. Clear DTC.
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), connector(s) and terminal(s).