P0129 - Barometric Pressure Too Low

Barometric pressure reading is lower than expected for current conditions.

Treat the code as the starting point: compare symptoms, likely causes, and repair paths before pricing parts or moving into an estimate.

Code Overview

Barometric pressure reading is lower than expected for current conditions.

Common Causes

• BARO/MAP sensor issue
• Wiring fault
• Restricted intake
• Sensor reference voltage problem

Diagnostic Steps

1. Compare BARO/MAP to local atmospheric pressure
2. Inspect vacuum routing and intake ducting
3. Verify reference voltage and ground

Likely Repairs & Cost Guides

Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.

Related OBD Codes

Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.

Next Steps

Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.