Code Definition

P0170 — Fuel Trim Malfunction (Bank 1)

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0170

P0170 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0170 is stored, the module has detected a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine.

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.

Because P0170 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The P0170 fault code is set when the Engine Control Module (ECM) identifies an issue with the fuel trim on Bank 1 of the engine. Fuel trim refers to the feedback control used by the ECM to maintain the optimal air-fuel mixture for combustion. The malfunction can be due to the ECM's compensation for rich or lean conditions beyond the normal range. This can be a result of various factors affecting the fuel or air entering the engine, sensor malfunctions, or exhaust issues. The code indicates that the ECM is struggling to keep the air-fuel mixture in balance, either adding too much fuel (rich con...

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