Code Definition

P1170 — HO2S Bank 1 Sensor 1 Circuit Fixed (Bank 1 Sensor 1)

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

About P1170

P1170 is a manufacturer-specific powertrain diagnostic trouble code recorded for Mazda vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1170 is stored, the module has detected a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; 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.

P1170 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

The Powertrain Control Module (PCM) relies on the rapidly changing voltage from the Bank 1 Sensor 1 upstream oxygen sensor to keep the fuel mixture at target in closed loop. DTC P1170 sets when the PCM sees the Bank 1 Sensor 1 circuit fixed, that is, the sensor voltage frozen at one level rather than crossing rich and lean as it should. The usual reasons are a sensor that has aged or been contaminated and can no longer respond, a wiring fault that clamps the signal, or a heater problem leaving the sensor too cold to generate a varying output. Symptoms include degraded fuel economy, light hesit...

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