Code Definition

P1156 — Fuel Select Switch Malfunction

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

About P1156

P1156 is a manufacturer-specific powertrain diagnostic trouble code. 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.

P1156 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 is set when the powertrain control module (PCM) detects an issue with the fuel select switch, which is used in bi-fuel or alternative fuel vehicles to switch between fuel types (e.g., gasoline and CNG/LPG). A malfunction in this switch or its circuit can prevent proper fuel selection, leading to drivability issues.

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