Approximately 5 volts is what you should be seeing at the TPS. The TPS output voltages are off.
P0123 Jeep - Throttle Position Sensor/Accelerator Position Pedal Circuit High Input.
Possible causes
- Faulty throttle position sensor
- Throttle position sensor harness is open or shorted
- Throttle position sensor circuit poor electrical connection
TPS TEST
The TPS is mounted on the throttle body. The TPS is a variable resistor that provides the Powertrain Control Module (PCM) with an input signal (voltage) that represents throttle blade position. The sensor is connected to the throttle blade shaft. As the position of the throttle blade changes, the resistance of the TPS changes. Along with inputs from other sensors, the PCM uses the TPS input to determine current engine operating conditions. In response to engine operating conditions, the PCM will adjust fuel injector pulse width and ignition timing.
The PCM supplies approximately 5 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5volts. This will vary in an approximate range of from .25 volts at minimum throttle opening (idle), to 4.8 volts at WOT wide open throttle.
Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.
The TPS is sensitive to heat, moisture, and vibration.
