Code Definition

P1151 — Long term fuel trim 1 bank 1 below lean limit

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

About P1151

P1151 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1151 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and 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.

P1151 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

Volkswagen and Audi engine management splits the learned long term fuel trim for each bank into two ranges, with Range 1 covering idle and lower load where intake vacuum is high and Range 2 covering higher load. DTC P1151 is set when the Range 1 long term fuel trim for Bank 1 exceeds its lean lower limit, meaning the ECM has added the maximum fuel it is allowed in that range and the mixture is still too lean. Because Range 1 reflects idle and low load operation, the fault points strongly toward unmetered air entering through a vacuum or intake leak, or a fuel delivery shortfall at low load. Wh...

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