P0129
Fix within 1-2 weeksYour engine's computer is getting a signal from the Barometric Pressure (BARO) sensor that's too high, indicating an issue with how it's reading atmospheric pressure.
Code P0129 means your barometric pressure sensor is sending a high voltage signal. Common causes: Faulty BARO sensor (80%), wiring issues (15%). Drivability: Yes, safe to drive, but fix within 1-2 weeks. Repair cost: $50-$200 DIY, $150-$500 professional.
Can I Drive With P0129?
Yes, safe to drive
No restrictions, but fix within 1-2 weeks to restore performance and fuel economy.
Stop driving immediately if: Flashing CEL, significant power loss, or engine stalling frequently
Symptoms of P0129
- 1Check Engine Light is on
- 2Reduced engine power or sluggish acceleration
- 3Poor fuel economy
- 4Rough idle or stalling
- 5Engine may be hard to start
Common Causes of P0129
Parts most likely causing this code, ranked by probability
A faulty BARO sensor sends incorrect voltage signals to the engine computer, leading to the P0129 code.
80% of P0129 cases are fixed by replacing this part
Damaged, corroded, or loose wiring and connectors to the BARO sensor can cause an erratic or high voltage signal.
15% of P0129 cases are fixed by repairing wiring or connectors
A rare internal fault within the engine computer can misinterpret or incorrectly process the BARO sensor signal.
5% of P0129 cases are fixed by replacing the ECM/PCM
Check These First (Before Buying Parts)
- Visually inspect the BARO sensor's electrical connector and wiring for any signs of damage, corrosion, or loose connections. Ensure it's securely plugged in.
- Clear the code with an OBD-II scan tool and drive the vehicle to see if the code immediately returns. Sometimes, it can be a temporary glitch.
How to Diagnose P0129
- 1Visually inspect the BARO sensor and its wiring harness for any obvious damage, corrosion, or loose connections.
- 2Use an OBD-II scan tool to monitor the BARO sensor's live data reading; compare it to the known atmospheric pressure for your altitude.
- 3Check the BARO sensor's voltage output and resistance using a multimeter, comparing readings to manufacturer specifications.
- 4If the sensor tests good, check the continuity and resistance of the wiring between the BARO sensor and the ECM/PCM.
- 5If all other components test good, consider a potential ECM/PCM issue, though this is a very rare cause.
P0129 on Popular Vehicles
Toyota Camry
2007-2024On many Camry models, the BARO sensor is integrated into the MAP sensor. A P0129 often indicates a fault with this combined sensor.
75% fixed by replacing the MAP/BARO sensor
Honda Accord
2003-2024Honda Accords frequently integrate the BARO sensor with the MAP sensor. P0129 typically points to a failure of this combined sensor or its wiring.
78% fixed by replacing the MAP/BARO sensor
Ford F-150
2004-2024For Ford F-150 trucks, the BARO sensor is often part of the MAP sensor assembly. A P0129 code usually means the MAP/BARO sensor is failing or there's a problem with its electrical connection.
82% fixed by replacing the MAP/BARO sensor
Frequently Asked Questions
What does P0129 mean?
P0129 indicates that your vehicle's engine computer has detected a higher-than-expected voltage signal from the Barometric Pressure (BARO) sensor. This sensor measures atmospheric pressure, which the computer uses to adjust fuel delivery and ignition timing.
Can I drive with P0129?
Yes, you can drive safely with a P0129 code, but you should fix it within 1-2 weeks. Your vehicle's performance and fuel economy will be reduced, and ignoring it can lead to other issues over time.
Will P0129 clear itself?
No, P0129 will not clear itself. The Check Engine Light will remain on until the underlying issue with the BARO sensor or its circuit is repaired and the code is manually cleared or the vehicle completes several drive cycles without the fault recurring.
How do I fix P0129 myself?
Start by inspecting the BARO sensor's wiring and connector for damage. If they look good, use a scan tool to verify the sensor's reading. If the reading is incorrect, replacing the BARO sensor (often integrated with the MAP sensor) is the next step. Clear the code after replacement.
How much does it cost to fix P0129?
A DIY fix for P0129 typically costs $50-$200 for a new BARO/MAP sensor. If you take it to a shop, expect to pay $150-$500, which includes parts and labor for diagnosis and replacement.
P0129 keeps coming back - why?
If P0129 keeps returning, it's likely due to an overlooked wiring issue, a faulty replacement sensor, or a rare problem with the engine computer itself. Double-check all connections and consider a more thorough diagnostic of the wiring harness.
Will P0129 fail emissions/smog test?
Yes, P0129 will cause your vehicle to fail an emissions or smog test. The Check Engine Light being on is an automatic failure in most states, and the incorrect BARO sensor readings can directly impact exhaust emissions.
What's the difference between P0129 and P0106?
P0129 specifically indicates a high voltage signal from the BARO sensor. P0106, on the other hand, means there's an issue with the Manifold Absolute Pressure (MAP) sensor's performance range or correlation with the BARO sensor. They are related as BARO and MAP sensors often work together, and sometimes the BARO sensor is integrated into the MAP sensor.
P0129 on Ford F-150?
On many Ford F-150 models, the BARO sensor is integrated into the MAP sensor. A P0129 on an F-150 often points to a failing MAP/BARO sensor or a wiring issue to that combined unit. Diagnosis should focus on checking the MAP/BARO sensor readings and its electrical connections.
Questions to Ask Your Mechanic
Did you check the live data from the BARO sensor with a scan tool?
Good answer: Yes, I monitored the BARO sensor reading and compared it to the local atmospheric pressure. It was reading X kPa, which is too high for our altitude.
What did you find when you inspected the wiring to the BARO sensor?
Good answer: I thoroughly checked the wiring harness and connector for any signs of corrosion, fraying, or loose pins. Everything looked solid, so we moved on to testing the sensor itself.
Repair Cost Estimate
DIY Repair
Parts only
$50-$200
Shop Repair
Parts + labor
$150-$500
Save $100-$300 by doing it yourself
Difficulty
intermediate
Time
1-2 hours
Intermediate - while replacing the sensor itself is often simple, proper diagnosis requires an OBD-II scan tool to monitor live data and confirm the sensor's reading.
Cost of Waiting
Ignoring P0129 can lead to consistently poor fuel economy, reduced engine power, and potentially increased emissions. While it won't cause immediate catastrophic failure, the engine's computer will struggle to make accurate fuel and timing adjustments, leading to inefficient operation and potentially premature wear on other components due to incorrect air/fuel mixtures.
While You're In There...
If the BARO sensor is integrated with the MAP sensor, it's often located near the air intake. Replacing a dirty air filter ensures optimal airflow and prevents future issues that could affect sensor readings.
If the BARO sensor is part of a MAF/MAP sensor assembly, cleaning the MAF sensor can help ensure accurate airflow readings, which are critical for the engine computer.
Tools You'll Need
- OBD-II Scan Tool
- Multimeter
- Basic hand tools (sockets, wrenches)
P0129 is a common sensor code that's usually straightforward to diagnose and fix. Most repairs involve replacing an affordable sensor, and your engine will regain its proper performance and fuel economy afterward.
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Your Next Steps
Step 1: Check the BARO sensor's wiring and connector for any visible damage or corrosion. Ensure it's fully seated.
Step 2: Use an OBD-II scan tool to check the live data from the BARO sensor. Compare its reading to the known atmospheric pressure for your current altitude. If the reading is significantly off, the sensor is likely faulty.
Step 3: If the sensor reading is incorrect, you'll likely need a new BARO sensor. In many vehicles, this sensor is integrated with the Manifold Absolute Pressure (MAP) sensor, so you might be replacing a MAP/BARO sensor assembly.