Code Definition

P1155 — Manifold Absolute Pressure sensor short to positive

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

About P1155

P1155 is a manufacturer-specific powertrain diagnostic trouble code recorded for Volkswagen vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1155 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a sensor-related fault — the reported value from the named sensor is out of spec.

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.

P1155 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

The manifold absolute pressure sensor reports intake manifold pressure to the Engine Control Module (ECM), which uses it together with other inputs to calculate load and set fuelling and ignition. DTC P1155 is stored when the ECM detects the manifold absolute pressure signal shorted to a positive supply, forcing the signal voltage abnormally high. A high signal makes the ECM read high manifold pressure, or high boost on a turbocharged engine, which it knows is implausible for the conditions. Symptoms can include poor running, incorrect fuelling, reduced power, and an illuminated check engine l...

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