P1129 Possible Causes
- Faulty Manifold Absolute Pressure Sensor
- Manifold Absolute Pressure Sensor harness is open or shorted
- Poor electrical connection in the Manifold Absolute Pressure Sensor circuit
How to Fix Code P1129?
Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light on (or Service Engine Soon Warning Light)
- Engine hard to start
- Rough or erratic idle speed
P1129 Meaning
The Manifold Absolute Pressure (MAP) sensor generates a signal proportional to the amount of vacuum in the intake manifold. The signal is sent to the Engine Control Module (ECM) and the information is used to control the air/fuel mixture ratio. A faulty MAP sensor can cause engine stalling, surging, or rough idle.