P2002
Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
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The P2002 code indicates that your diesel particulate filter (DPF) on bank 1 is not filtering exhaust soot as effectively as it should. The DPF is an emissions device found on 2007 and newer diesel vehicles that captures and periodically burns off soot particles from the exhaust. When the filter becomes too clogged or the system cannot properly regenerate, this code is triggered.
This issue commonly occurs in vehicles that spend a lot of time in stop-and-go city driving, as the DPF needs sustained highway speeds and higher exhaust temperatures to perform its self-cleaning regeneration cycle. Poor-quality diesel fuel and oil that produces excessive soot can also accelerate filter clogging.
Before spending money on parts, try a highway regeneration drive — maintain speeds above 40 mph at around 1,400-2,000 RPM for 20 to 30 minutes to generate enough heat to burn off accumulated soot. If that doesn't clear the code, have the DPF professionally cleaned or the pressure sensors inspected. A full DPF replacement is expensive ($1,000-$2,500+) and should be a last resort after other solutions have been exhausted.
Severity
Symptoms
- •Check engine light or DPF warning light illuminated
- •Noticeable loss of power and sluggish acceleration
- •Increased black smoke or soot from the exhaust
- •Reduced fuel economy compared to normal
- •Vehicle may enter limp mode limiting speed
Likely Causes
The DPF collects soot from diesel exhaust over time. Excessive city driving without highway regeneration cycles allows soot to build up beyond the filter's capacity, reducing its efficiency below the PCM's threshold.
The automatic regeneration process that burns off accumulated soot may fail due to short trip driving patterns, a faulty fuel injector used for regeneration, or a malfunctioning exhaust temperature sensor preventing the system from reaching proper burn-off temperatures.
The sensors that measure exhaust pressure before and after the DPF can fail or become clogged with soot, providing inaccurate readings to the PCM and falsely indicating the filter is not performing efficiently.
Leaks in the exhaust system between the engine and the DPF allow unfiltered exhaust to bypass the filter or alter pressure readings, causing the PCM to detect reduced filter efficiency even when the DPF itself may be functional.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Perform a forced DPF regeneration by driving at highway speeds (above 40 mph) for 20-30 minutes
- Clean the DPF using a professional cleaning service or DPF cleaning additive
- Replace the DPF differential pressure sensor
- Replace the diesel particulate filter if cleaning is unsuccessful
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