Code Definition

P1129 — Manifold Absolute Pressure (MAP) higher than expected

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

About P1129

P1129 is a manufacturer-specific powertrain diagnostic trouble code recorded for Honda vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1129 is stored, the module has detected a signal or supply voltage higher 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.

P1129 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 measures intake manifold pressure and reports it to the Powertrain Control Module (PCM) as the primary load signal for fuel and ignition control. DTC P1129 is a Honda specific code that sets when the PCM detects the MAP sensor reading is higher than the value expected for the current throttle position, engine speed, and load. A higher than expected MAP signal means the sensor is reporting less vacuum, or more absolute pressure, than the operating conditions should produce, which can come from a faulty sensor, a disconnected or leaking sensor vacuum h...

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