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DTC codes / Nissan codes / P1122

P1122 · NissanThrottle Position Higher Than Expected

P1122 on a Nissan means the engine control module (ECM) has calculated that the throttle position sensor signal is higher than it should be for the current operating conditions, indicating the throttle plate is being reported as more open than commanded. The ECM compares the throttle position sensor voltage against expected values from the accelerator pedal position and mass airflow sensor, and sets this code when the signal exceeds the calibrated threshold.

SystemPowertrain
Code typeNissan specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering

Symptoms you may notice

  • Illuminated check engine light, often with no other noticeable symptoms
  • Reduced engine power or limp mode, limiting acceleration
  • Poor fuel economy due to the ECM enriching the mixture based on a falsely high throttle reading
  • Unstable or high idle speed
  • Hesitation or stumble during acceleration
  • In rare cases, the engine may stall or refuse to start

Common causes, most likely first

  1. Dirty or carbon-fouled throttle body causing the plate to rest slightly open
  2. Faulty throttle position sensor (TPS) or accelerator pedal position sensor
  3. Wiring damage or poor connection at the TPS or throttle body connector
  4. Sticking or binding throttle plate or linkage
  5. Intake air leak downstream of the throttle body, confusing the ECM's airflow calculation
  6. Failed or contaminated mass airflow sensor (MAF) sending skewed readings
  7. ECM software calibration issue or internal fault (less common)

How to diagnose and fix it

  1. Inspect the throttle body for carbon buildup and clean it with throttle body cleaner, then perform a throttle relearn procedure
  2. Check the TPS and accelerator pedal position sensor connectors for corrosion, loose pins, or damaged wiring
  3. Measure TPS voltage with a scan tool or multimeter and compare to specification through the full throttle range
  4. Check for intake air leaks between the MAF sensor and throttle body using a smoke test or carb cleaner
  5. Clean or replace the mass airflow sensor if readings are inconsistent with actual airflow
  6. Perform a throttle position sensor relearn or idle air volume relearn using a scan tool
  7. If all else fails, reprogram or replace the ECM after confirming all sensors and wiring are good

Why a clean throttle body often fixes P1122

  • Carbon buildup on the throttle plate is the most common cause on high-mileage Nissan engines, and a simple cleaning with a relearn often resolves the code without replacing any parts.
  • A dirty mass airflow sensor can skew the ECM's airflow calculation and cause it to interpret a normal TPS signal as too high, so always check MAF readings before condemning the TPS.
  • After cleaning or replacing the throttle body, a throttle position relearn procedure is mandatory on many Nissan models; skipping it will cause the code to return immediately.
  • P1122 can be set by a loose or cracked intake tube between the MAF and throttle body, which lets unmetered air in and confuses the ECM's throttle expectations.
  • Do not assume the TPS is faulty just because this code is stored; the sensor is often the victim of a mechanical issue like a sticking throttle plate or a wiring fault.

Can I keep driving with P1122?

You can usually drive the vehicle to a repair shop, but avoid aggressive acceleration or heavy loads because the ECM may be limiting power and the engine could enter limp mode. If the vehicle stalls or loses power suddenly, pull over safely and arrange a tow.

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 Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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