The Quick Answer above is the generic definition. What follows is what is documented for the Toyota models that log P0121, checked against manufacturer data and owner reports.
DTC/P0121·Toyota
P0121 on Toyota: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Toyota
P0121 on a Toyota means the throttle position sensor A signal is in range electrically but doesn't match what the ECU expects from RPM, MAF, and pedal inputs. Result: the ECU stops trusting the throttle and usually forces limp mode.
Repair cost on Toyota€48 - €730
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Toyota Camry
2002-2011 (2AZ-FE 2.4L, ETCS-i electronic throttle)The 2AZ-FE throttle body (Denso 22030-28070) has a known internal TPS wear issue. Cleaning gives a few weeks of relief at most; the whole unit typically needs replacing. After swap, disconnect battery for 60 seconds and let the ECU relearn idle over 10 minutes of drive time.
What causes P0121 on a Toyota?
Beyond the generic causes listed on the main P0121 page, these are the documented Toyota-specific patterns:
Toyota CamryInternal TPS track wear inside the 22030-28070 throttle body
Toyota CamryIAC passages coked with carbon on higher-mileage examples
How to diagnose P0121 on a Toyota with OBD2
Follow these steps to pinpoint the root cause of P0121:
- Scan for all stored and pending codes. P0121 rarely shows alone; sister codes like P0122, P0123, or P2135 point straight at the fault
- With key on engine off, log TPS1/TPS2 (or APP1/APP2) voltages. Expect roughly 0.5-0.9V closed and 4.0-4.5V wide open, with the two signals tracking correctly
- Slowly sweep the throttle from closed to WOT while logging. Any dropout, spike, or flat spot in the trace is a worn sensor track
- Inspect the TPS connector for bent pins, green corrosion, or oil contamination pooling from a leaking valve cover gasket
- Back-probe the 5V reference and ground at the sensor. Expect close to 5.0V reference and under 0.1V on ground with key on
- Remove the intake boot and check the throttle plate. Clean with throttle body cleaner if coked, but don't force a drive-by-wire plate open by hand
- If the sensor is integrated in the throttle body and readings are still erratic, replace the throttle body assembly
- After any repair or cleaning, run the manufacturer's throttle body / idle relearn procedure with a capable scan tool
How much does P0121 cost to fix on a Toyota? (EUR)
Estimated repair costs for P0121 in EUR, compiled across makes. Toyota costs typically sit in the middle of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0121 on Toyota
These codes commonly cluster with P0121 on Toyota vehicles:
Looking for the full P0121 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0121 guideSkanyx · Toyota
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