When the 2023 Chrysler Pacifica sets P0123, the TPS is sending higher voltage than expected. This indicates the ECU thinks the throttle is more open than it actually is, potentially causing high idle, surging, or improper fuel delivery.
Understanding P0123
P0123 indicates TPS circuit voltage exceeds normal thresholds. Normal TPS output ranges from approximately 0.5V (closed) to 4.5V (wide open). If voltage exceeds approximately 4.8V or shows high readings at closed throttle, P0123 sets.
Pacifica Engine and Throttle System
The 2023 Pacifica uses a 3.6L Pentastar V6 or Pacifica Hybrid powertrain. Both use electronic throttle control where accurate TPS readings are essential. High TPS readings cause the ECU to think more airflow is entering than actually is.
Common Causes of High TPS Signal
A shorted TPS sensor or wiring causes high voltage output. If the signal wire contacts the 5V reference line or has internal shorting, voltage stays high regardless of throttle position.
A failed TPS stuck in high-output mode sends constant high voltage. Internal sensor failure can lock output at maximum.
Water intrusion in the throttle body connector can cause shorts between terminals. Moisture creates conductive paths that elevate signal voltage.
Diagnostic Approach
Monitor TPS voltage at closed throttle—if it shows high voltage (3V+ at idle), the signal is abnormally high. Disconnect the TPS connector and check if voltage drops to zero (should be near 0V with sensor disconnected). If still high, there's a short in the wiring. If voltage drops, the sensor is shorted internally.