Hyundai Kia Error Code P1121: How to Fix It

Q: Can I drive with P1121 error code?

You should avoid driving with P1121 as it can cause unpredictable throttle response, poor acceleration, and potential stalling. If you must drive, keep speeds low and avoid highway driving until the issue is resolved.

Q: How much does it cost to fix P1121?

DIY repair costs range from $30-80 for a new TPS, plus $10-20 for wiring supplies if needed. Professional repair typically costs $150-300 including parts and labor, depending on whether wiring harness work is required.

Q: What causes P1121 in Hyundai and Kia vehicles?

Common causes include a faulty throttle position sensor, damaged wiring harness, corroded connectors, blown fuses in the ECM power circuit, or rarely, a faulty engine control module. Wiring issues are most common in older vehicles.

Q: Will P1121 cause my car to fail emissions testing?

Yes, P1121 will likely cause your vehicle to fail emissions testing as it indicates a malfunction in the engine management system. The error code must be resolved and the readiness monitors must complete before passing inspection.

Q: How do I know if my TPS is bad?

Signs of a bad TPS include erratic idle, hesitation during acceleration, poor fuel economy, intermittent stalling, and the check engine light. A multimeter test showing irregular voltage output or no signal change when moving the throttle confirms a faulty TPS.

Abstract

Error code P1121 indicates a power circuit fault in your Hyundai or Kia's throttle position sensor (TPS). This means the sensor isn't receiving proper voltage, which can cause poor acceleration, rough idling, and reduced fuel economy. While this is a high-severity issue that affects drivability, most causes can be diagnosed and fixed with basic tools.