Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
DTC P0121: Throttle Position Sensor Circuit Range/Performance: Notes
2004 Toyota Matrix XR, FWD, StandardSECTION Notes
WARNING: This page is about a different car, the 2003 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If DTCs related to TPS, IAT sensor, MAF meter, ECT sensor, APP sensor & VPS are output simultaneously, the E2 sensor ground circuit at ECM 31-pin connector E7 terminal No. 11 (Black/White wire) may be open. For ECM electrical connector terminal identification, see Figure. It may be necessary to check Black/White wire between splice I13 and ECM 31-pin connector E7 terminal No. 11. Splice I13 is located behind passenger's side of instrument panel. See Figure.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.