Code Definition

P1168 — Primary Heated Oxygen Sensor (#1) low input

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

About P1168

P1168 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 P1168 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and 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.

P1168 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 P1168 is a Honda specific code indicating the primary, or upstream, Air Fuel Ratio sensor (Sensor 1) signal is reading lower than the valid range. The Powertrain Control Module (PCM) monitors the sensor circuit voltage and sets P1168 when the input stays below the threshold expected for a working sensor, which generally means a short to ground in the signal circuit, an open in the sensor or its wiring, or a failed sensor. With the signal pinned low the PCM cannot use it for closed loop fuel control and falls back to a default fuel strategy. The driver may notice increased fuel consumption,...

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