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. Low boost pressure reduces engine power and fuel efficiency, and may trigger the check engine light.
01. Most Common Causes
- Boost leak in intake system (hoses, intercooler, gaskets)
- Faulty turbocharger wastegate or actuator
- Clogged or restricted air filter or exhaust system
- Malfunctioning boost pressure sensor or wiring
- Turbocharger mechanical failure (worn bearings, damaged impeller)
02. Symptoms You Will Notice
- Check engine light illuminated
- Loss of engine power and poor acceleration
- Whistling or hissing noise from turbo area
- Excessive black smoke from exhaust under load
- Reduced fuel economy
03. 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: Check air filter and exhaust for restrictions.
Step 4: Test boost pressure sensor and wiring with a multimeter.
Step 5: Perform a boost leak test using a smoke machine or pressure tester.
Step 6: Inspect wastegate operation and turbocharger for shaft play or damage.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as low boost can cause poor performance and potential damage to the turbo or engine. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
Costs vary widely depending on the cause. A simple boost leak repair may cost $150-$300, while turbocharger replacement can range from $1,000 to $3,000.