P0129
P0129-BAROMETRIC PRESSURE OUT OF RANGE LOW
For a complete wiring diagram refer to the Wiring Information Electrical Diagrams.
The Powertrain Control Module (PCM) checks if the barometric pressure sensor signal is too low by performing two tests. One trip fault. Three good trips to turn off the MIL:
Lower Limit: The barometric pressure value is checked against a lower limit.
- When Monitored:
The ignition is on.
- Set Condition:
The PCM checks if the barometric pressure signal is lower than an acceptable value.
Rationality: The barometric pressure is compared with manifold pressure while the engine is running.
- When Monitored:
The engine is running.
- Set Condition:
The PCM checks if the barometric pressure is below the manifold pressure by more than a certain amount.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Pre-Diagnostic Troubleshooting Procedure
POWERTRAIN CONTROL MODULE (PCM)
NOTE: Diagnose and repair any MAP sensor circuit DTCs before continuing with this test.
NOTE: Since the barometric pressure sensor is located inside the PCM, if the PCM is warm and gets cooled down quickly, this can result in a pressure drop inside the PCM which can cause this DTC to set. The driver should be asked if the fault occurred after the vehicle went through a carwash or driven through water.
1. Look for any chafed, pierced, pinched, or partially broken wires.
2. Look for broken, bent, pushed out or corroded terminals.
3. Look for a restriction in the PCM breather.
4. Search for any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM Verification Test.PCM Verification Test
No
- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test.PCM Verification Test