Code Definition

P1221 — Throttle motor position sensor 1 & 2 circuit fault

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Honda

About P1221

P1221 is a manufacturer-specific powertrain diagnostic trouble code recorded for Honda vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1221 is stored, the module has detected a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1221 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

DTC P1221 is a Honda specific code indicating a circuit fault affecting both throttle position sensor 1 and throttle position sensor 2 in the electronic throttle body, or a correlation failure between the two. The Powertrain Control Module (PCM) expects the two throttle position signals to track each other in a fixed relationship as the plate moves. P1221 sets when both signals are faulty at once or when they disagree by more than the allowed amount, which often points to a shared reference or ground fault, a connector problem, or an internal throttle body failure rather than a single sensor. ...

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