Code Definition

P1511 — Boost Pressure Low

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

About P1511

P1511 is a manufacturer-specific powertrain diagnostic trouble code recorded for Toyota vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1511 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

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.

P1511 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 fault code sets when the Engine Control Module (ECM) detects that actual turbocharger boost pressure is lower than the target value for the current engine load, throttle position, and engine speed. The ECM compares the manifold absolute pressure or boost pressure sensor reading against the commanded boost to monitor turbocharger output. If the actual boost falls short of target by more than a calibrated amount for a set time, the ECM stores this underboost code. The driver typically notices reduced power and acceleration, possible black smoke on diesels, and a check engine light.

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