P0129 Fault Code

Barometric Pressure Too Low

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0129 fault code indicates that the vehicle's Engine Control Module (ECM) has detected that the barometric pressure is lower than expected. This can affect the air-fuel mixture and overall engine performance.

• Barometric pressure is a measure of air pressure in the atmosphere, which can fluctuate based on altitude and weather conditions.
• A proper barometric pressure reading is crucial for the ECM to adjust the fuel mixture for optimal engine combustion and efficiency.

What are the symptoms of the P0129 code?

Common symptoms associated with the P0129 code include:

• Illuminated check engine light
• Decreased engine performance
• Reduced fuel efficiency
• Rough idle or stalling
• Difficulty starting the engine

What causes the P0129 code?

Several factors can trigger a P0129 code, including:

• Faulty barometric pressure sensor
• Damaged or disconnected vacuum hoses
• ECU or wiring issues
• Environmental factors, such as high altitude or low ambient pressure
• Engine intake leaks leading to incorrect sensor readings

How to fix P0129?

To resolve a P0129 error code, consider the following fixes:

• Inspect and replace the barometric pressure sensor if faulty.
• Check and repair any damaged or disconnected vacuum lines.
• Clear any stored codes and test drive the vehicle to see if the code returns.
• If the issue persists, check the engine control unit (ECU) for faults or reprogramming needs.
• Ensure that environmental factors are taken into account, such as operating at a high altitude without adjustments.