Diesel Particulate Filter Efficiency Below Threshold Bank 1
The P2002 code indicates that the diesel particulate filter (DPF) is not trapping soot efficiently, often due to clogging or failure. This triggers the check engine light and may lead to reduced engine performance and increased emissions.
1. Most Common Causes
- Excessive DPF soot loading from prolonged low-speed, urban driving
- Failed active regeneration system (post-injection injector, electric heater, or dedicated fuel injector)
- Physical damage or melting of the DPF ceramic substrate due to overheating during a failed regeneration
- Faulty DPF differential pressure sensor or clogged/broken sampling lines
- Faulty DPF temperature sensor (pre- or post-filter)
- Intake or exhaust leak altering pressure readings
- Engine oil or coolant contaminating the DPF (turbo failure, valve seals, or injectors)
- Outdated ECM/PCM software with incorrect efficiency threshold calibrations
2. Symptoms You Will Notice
- Check engine light illuminated
- Reduced engine power and acceleration
- Increased fuel consumption
- Regeneration cycle occurring more frequently or failing
3. Step-by-Step Diagnosis
Step 1: Scan for codes and check freeze frame data to confirm P2002.
Step 2: Inspect DPF pressure sensor readings and compare to specifications.
Step 3: Check for exhaust leaks using a smoke machine or visual inspection.
Step 4: Perform a forced regeneration using a scan tool to clear the DPF.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the DPF may become completely clogged, leading to costly repairs or a no-start condition.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. DPF replacement can range from $1,000 to $4,000 depending on the vehicle.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.