Honda P1129: Manifold Absolute Pressure (MAP) Sensor Signal Higher Than Expected

What Does The Honda P1129 Code Mean?

The manifold absolute pressure (MAP) sensor senses manifold absolute pressure (vacuum) and converts it into electrical signals. The MAP sensor outputs low signal voltage at high-vacuum (throttle valve closed) and high signal voltage at lowvacuum (throttle valve wide open).

The engine control module (ECM) compares a predetermined MAP value at a given throttle position and manifold absolute pressure to the output voltage value of the MAP sensor.

If the MAP sensor outputs high voltage during fuel cut-off operation for deceleration with the throttle valve fully closed, which should make the manifold absolute pressure lower, the ECM detects a malfunction and stores a DTC.

What Are The Potential Causes Of The Honda P1129 Code?

• Vacuum leaks
• Poor connections or loose terminals at the MAP sensor and the PCM
• Faulty MAP sensor

Recommended Parts

Below are some recommended auto parts to help you address the trouble code affecting your vehicle and get it running smoothly again:

>>> WORKPRO 582-piece Crimp Terminals, Wire Connectors, Heat Shrink Tube, Electrical Repair Kit
>>> CrocSee 250 Pieces - Car Fuses Assortment Kit
>>> APDTY Manifold Pressure Sensor

Note: During the purchasing process, please check carefully whether the part you want to buy fits your car!

Check This Video For Reference

Reference Sources

• Honda DTC Codes for P1129 – Page 1.
• Technical Service Bulletins 03-020 for P1129 – American Honda Motor Co., Inc.; pages 129-131.