Engine-Codes - BMW - P129B BMW

P129B BMW Code - Manifold Pressure Sensor Rationality Check

- Code Popularity: 6,495 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
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What are the Possible Causes of the DTC P129B BMW?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Absolute Pressure Sensor
  • Absolute Pressure Sensor harness is open or shorted
  • Absolute Pressure Sensor circuit poor electrical connection
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How to Fix the DTC P129B BMW?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P129B BMW code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P129B BMW Code Mean?

The absolute pressure in the intake manifold is measured by the manifold pressure sensor. If the engine is not running (engine speed = 0) the measured pressure of the intake manifold pressure sensor located downstream of the throttle body is the same as the measured pressure of the boost pressure sensor in the intake manifold system upstream of the throttle.
In addition, in the ECU, the ambient pressure is measured. If the measured manifold pressure is different from both of the other two pressure measurements a fault of the manifold pressure measurement is detected. Both of the differences (Manifold Pressure to Boost Pressure and Manifold Pressure to Ambient Pressure) must exceed a calibratable threshold depending on the sensor tolerances.

P129B BMW Code - Manifold Pressure Sensor Rationality Check

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