Low Pressure Fuel System Pressure Too High
The P008B code indicates that the engine control module (ECM) has detected excessive fuel pressure in the low-pressure fuel system, typically between the fuel tank and the high-pressure fuel pump. This can be caused by a faulty fuel pressure regulator, a restricted fuel return line, a malfunctioning fuel pump control module, or a stuck-open fuel pressure relief valve. High fuel pressure can lead to rich fuel mixture, reduced fuel economy, and potential damage to fuel injectors or the high-pressure pump.
1. Most Common Causes
- Faulty fuel pressure regulator
- Restricted or blocked fuel return line
- Malfunctioning fuel pump control module
- Stuck-open fuel pressure relief valve
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation
- Black smoke from exhaust (rich mixture)
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P008B and check freeze frame data.
Step 2: Inspect fuel pressure with a manual gauge; compare to manufacturer specs.
Step 3: Check fuel return line for kinks, clogs, or restrictions.
Step 4: Test fuel pressure regulator operation and replace if faulty.
Step 5: Verify fuel pump control module signals and replace if necessary.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as high fuel pressure can cause engine damage, poor performance, and increased emissions. Have it diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $50 to $150 for parts like a fuel pressure regulator, plus labor if needed. More extensive issues may cost more.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.