Code Definition

P1156 — Manifold Absolute Pressure sensor open or shorted to ground

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

About P1156

P1156 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 P1156 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; 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.

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

The Manifold Absolute Pressure (MAP) sensor reports intake manifold pressure to the Engine Control Module (ECM), which uses it to calculate engine load and, on turbocharged engines, boost. DTC P1156 is set when the ECM detects that the MAP sensor signal circuit is open or shorted to ground, so the expected signal voltage is missing or pulled low. With no usable pressure signal the ECM falls back to a substitute load value and may limit performance. When this code is stored the driver may notice reduced power, hesitation, poor driveability and incorrect fuelling while the engine runs on the bac...

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