Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the computer in your car thinks the air pressure in the engine is too high, which doesn't make sense based on other information it has.
The engine control module (ECM) detects that the manifold absolute pressure (MAP) sensor reading is higher than expected, indicating a potential issue.
The P129D code is triggered when the ECM receives a signal from the MAP sensor that exceeds the maximum expected pressure value. This could indicate a sensor malfunction, wiring issue, or a problem with the engine's air intake system.
• Check Engine Light is on
• Poor engine performance
• Decreased fuel efficiency
• Faulty MAP sensor
• Wiring issues or poor electrical connections
• Vacuum leaks in the intake manifold
MAP Sensor: Manifold Absolute Pressure Sensor, measures the pressure in the intake manifold.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the MAP sensor and its wiring for damage.
• Check for vacuum leaks in the intake manifold.
• Replace the faulty MAP sensor.
• Repair or replace damaged wiring or connectors.
• Fix any vacuum leaks found in the intake system.
• OBD-II scanner
• Multimeter
• Vacuum gauge
$100 - $300
Moderate
• Chevrolet Silverado
• Ford F-150
• Toyota Camry
• Regularly inspect and maintain the intake system.
• Ensure all sensors are clean and functioning properly.
• Check for and repair any vacuum leaks promptly.
Sensor Issue
• Do not ignore the Check Engine Light.
• Get the vehicle inspected by a professional if unsure.
• Regular maintenance can help prevent this issue.
Check with your vehicle manufacturer for warranty coverage on engine sensors.
This code has been associated with sensor malfunctions and intake system issues in various vehicle models.
Moderate – It should be addressed soon to prevent further engine performance issues.
Driving with a faulty sensor can lead to increased emissions and may not comply with local regulations.
• Engine at operating temperature
• Vehicle at idle
The MAP sensor is typically located on the intake manifold or near the throttle body.
Q: Can I drive with a P129D code?
A: It's not recommended to drive for extended periods as it can affect engine performance and fuel efficiency.
Q: How can I prevent a P129D code?
A: Regular maintenance and inspections of the intake system and sensors can help prevent this issue.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
View on Amazon
Universal · Torque wrench
Useful when reassembly torque matters for wheel, suspension, and under-hood fasteners.
Useful when wheel, hub, or suspension hardware needs correct reassembly torque.
View on Amazon
Universal · Drive-on ramps
Helpful for safer access underneath the vehicle during exhaust, EVAP, and underbody inspection work.
Helpful for safer access during underbody inspection work.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.