OBD2 Car ScannerWhat does P0129 mean?
P0129 stands for Barometric Pressure Too Low. The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Powertrain codes cover the engine, transmission and emissions. When the car's computer sees a reading outside its normal range, it stores this code and may turn on a warning light on the dashboard.
Common causes
- Vacuum or intake air leaks
- Dirty or faulty mass airflow (MAF) sensor
- Faulty oxygen sensor or its wiring
- Fuel pressure problems (pump, filter or regulator)
- Clogged or leaking fuel injectors
What to do
- Read all stored and pending codes with a scanner. Several codes together often point to one cause.
- Note the freeze frame data (speed, temperature, load) recorded when the code was set.
- Inspect the wiring and connectors of the part named in the code for damage, corrosion or looseness.
- Fix the most likely and cheapest cause first, then clear the code and drive to see if it comes back.
Read this code from your own car
Plug in a cheap ELM327 adapter and the app shows every fault code, what it means and how to fix it.
Frequently asked questions
What does P0129 mean?
P0129 means “Barometric Pressure Too Low”. It belongs to the fuel and air metering group: The engine computer has found a problem with how fuel and air are measured or mixed. This affects fuel economy, emissions and sometimes how smoothly the engine runs.
Is it safe to drive with P0129?
You can usually drive carefully for a short time, but fix it soon to avoid further damage or higher fuel use.
How do I clear P0129?
Fix the cause, then clear the code with an OBD2 scanner or app. If the fault is still there, the code will come back.
Related codes
- P0125Insufficient Coolant Temperature for Closed Loop Fuel Control
- P0126Insufficient Coolant Temperature for Stable Operation
- P0127Intake Air Temperature Too High
- P0128Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)
- P012ATurbocharger/Supercharger Inlet Pressure Sensor Circuit (Downstream of throttle valve)
- P012BTurbocharger/Supercharger Inlet Pressure Sensor Circuit Range/Performance (Downstream of throttle valve)
- P012CTurbocharger/Supercharger Inlet Pressure Sensor Circuit Low (Downstream of throttle valve)
- P012DTurbocharger/Supercharger Inlet Pressure Sensor Circuit High (Downstream of throttle valve)
Code meanings can vary by manufacturer. This page is general guidance, not a repair manual. Always confirm the cause before replacing parts.