Turbo Boost Pressure Low
The P1247 code indicates that the engine control module (ECM) has detected that the actual turbocharger boost pressure is significantly lower than the desired boost pressure. This can be caused by a variety of issues including boost leaks, faulty turbocharger components, or sensor malfunctions. The ECM monitors boost pressure via the manifold absolute pressure (MAP) sensor and compares it to the target boost based on engine load and RPM. A persistent low boost condition can lead to reduced engine power, poor acceleration, and increased fuel consumption.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Loss of engine power and sluggish acceleration
- Whistling or hissing noise from turbo area
- Poor fuel economy
- Excessive black smoke from exhaust
2. Most Common Causes
- Boost leak in intake system (hoses, intercooler, gaskets)
- Faulty turbocharger wastegate or actuator
- Malfunctioning MAP or boost pressure sensor
- Clogged or restricted air filter or intake
- Exhaust restriction (catalytic converter, DPF)
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Visually inspect all boost hoses, intercooler, and connections for leaks or damage.
Step 3: Test the MAP sensor and boost pressure sensor with a multimeter or scan tool.
Step 4: Check turbocharger wastegate operation and actuator for proper movement.
Step 5: Perform a boost leak test using a smoke machine or pressure tester.
Step 6: Inspect air filter and intake for restrictions; check exhaust backpressure.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code as low boost can cause reduced power and may lead to further turbo or engine damage. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost varies depending on the cause. A simple boost leak repair may cost $150-$300, while replacing a turbocharger can range from $1,000 to $3,000 or more.
5. Commonly Affected Makes
This is a manufacturer-specific code. The exact manufacturer is not confirmed in our current database.