Code Definition

P1171 — Fuel mixture lean during acceleration

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

About P1171

P1171 is a manufacturer-specific powertrain diagnostic trouble code recorded for Acura vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

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.

P1171 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

This code relates to fuel mixture control under load. During acceleration the Engine Control Module (ECM) commands additional fuel enrichment to match the increased airflow, and it monitors the primary oxygen sensors to confirm the mixture is correct. DTC P1171 sets when the ECM detects a lean air fuel condition, meaning excessive oxygen in the exhaust, during an acceleration window where enrichment is expected. This indicates fuel delivery is failing to keep up with airflow demand. The fault must persist through a monitored acceleration event to store. The driver typically notices hesitation,...

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