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DTC codes / Ford codes / P1123

P1123 · FordThrottle Position Sensor In Range But Higher Than Expected

P1123 on Ford vehicles means the powertrain control module (PCM) is receiving a throttle position sensor (TPS) signal that is electrically valid but sits higher than the expected value for the current operating conditions. The PCM compares the TPS voltage against a predicted range based on engine speed, load, and pedal input, and it flags this code when the sensor reports a consistently elevated throttle angle without an out-of-range circuit fault.

SystemPowertrain
Code typeFord specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Often no symptoms besides the warning light, especially if the offset is small
  • A slightly high or fluctuating idle speed that may feel like the throttle is being held open
  • Poor fuel economy because the PCM fuels for a larger throttle opening than actual airflow supports
  • Hesitation or a soft throttle response when pulling away from a stop
  • In some cases, an automatic transmission that shifts late or holds gears longer than expected
  • Intermittent cruise control dropout if the PCM sees the TPS value as inconsistent with vehicle speed

Common causes, most likely first

  1. A worn or contaminated throttle position sensor that has drifted high in its resistance sweep
  2. A sticking or carbon-fouled throttle plate that holds the blade slightly open at rest
  3. A misadjusted or stretched throttle cable that keeps light tension on the throttle lever
  4. Corroded or partially backed-out pins in the TPS connector or PCM harness causing added resistance
  5. A faulty accelerator pedal position sensor on drive-by-wire Fords sending a slightly high request
  6. An intake air leak downstream of the throttle body that the PCM misinterprets as extra throttle opening
  7. A PCM calibration issue or outdated software that sets a tighter-than-necessary TPS expected range

How to diagnose and fix it

  1. Connect a scan tool and read live TPS voltage at closed throttle and at wide-open throttle, comparing against Ford's specification for the engine
  2. Inspect the throttle body bore and plate for carbon buildup, then clean with throttle-body cleaner and recheck the closed-throttle TPS voltage
  3. Check the throttle cable and cruise control linkage for binding or excess tension, and adjust or replace as needed
  4. Backprobe the TPS signal, reference, and ground wires at the sensor and at the PCM to look for voltage drops or intermittent resistance
  5. Perform a wiggle test on the TPS connector and harness while watching live data to catch an intermittent high reading
  6. If voltage is high at the sensor with the plate fully closed and the wiring is good, replace the TPS and clear the code
  7. On drive-by-wire Fords, check for PCM software updates and perform a throttle body relearn or idle relearn after any repair

Why a clean throttle body often fixes P1123

  • Carbon buildup on the throttle plate is the most commonly missed cause because the plate rests slightly open, raising TPS voltage without ever setting a circuit code.
  • A TPS can pass a simple resistance sweep test and still set P1123 because the drift is small and only appears under specific temperature or vibration conditions.
  • On Ford drive-by-wire systems, a tired accelerator pedal sensor can command a slightly high throttle angle that the PCM logs as a high TPS reading even though the throttle body itself is fine.
  • An intake leak between the throttle body and the engine can make the PCM expect a different TPS value at idle, so always check for unmetered air before condemning the sensor.
  • P1123 does not mean the TPS circuit is broken; a broken or shorted circuit sets a different code, so replacing the sensor without checking live data often wastes money.

Can I keep driving with P1123?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration and towing until the fault is diagnosed because a high TPS reading can cause poor fueling and delayed transmission shifts. If the idle becomes erratic or the engine stalls, stop driving and have it inspected promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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