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Information only. This page provides general educational information about fault code P1121. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.

Recommended next steps

Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.

What does P1121 mean?

P1121 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Throttle Position Sensor Intermittent High Input.

Manufacturer-specific notes

Some manufacturers publish additional definitions or variations for this code. Always cross-check with your vehicle's own service documentation.

Acura Throttle Position Sensor Intermittent High Input
Cadillac TP Sensor Circuit High Input (Intermittent)
Chevrolet TP Sensor Circuit High Input (Intermittent)
Ford Throttle Position Sensor A Inconsistent With MAF/MAP Sensor
GMC TP Sensor Circuit High Input (Intermittent)
Honda TP Sensor Input Lower Than Expected
Hyundai Throttle Position Sensor A Inconsistent With MAF/MAP Sensor
Jaguar Throttle Position Sensor A Inconsistent With MAF/MAP Sensor
Kia THROTTLE POSITION SIGNAL CIRCUIT MALFUNCTION
Land Rover Throttle Position Sensor A Inconsistent With MAF/MAP Sensor
Lexus ETCS Accelerator Pedal Position Sensor Performance
Mazda Throttle Position Signal Not Consistent With MAF Signal
Subaru Starter Circuit Switch High Input
Toyota ETCS Accelerator Pedal Position Sensor Performance
Vauxhall Throttle Position Sensor A Inconsistent With MAF/MAP Sensor
Volvo Throttle Position Sensor A Inconsistent With MAF/MAP Sensor

About Electrical & Sensors codes

Codes in the Electrical & Sensors category.

P1121 is one of 4,010 codes in this category. Browse all Electrical & Sensors codes →

What we know about P1121 specifically

We record the SAE J2012 standardised definition and the system this code belongs to, but we have not yet published detailed driver-reported symptoms, common causes, or step-by-step diagnostic guidance for P1121.

Rather than invent that information by generating generic content from a template, we leave it out. For specific guidance, the most reliable sources are:

  • your vehicle's own service manual or manufacturer-specific technical bulletins
  • a qualified mechanic with a manufacturer-level diagnostic tool
  • a marque specialist familiar with your make and model

Spotted an issue or have something to add? Mechanics, technicians, and drivers who have first-hand experience with P1121 can submit a correction or expansion. We review every submission before publishing, mechanic submissions are prioritised.

Information only, not professional advice

The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →

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