The OBD2 code P2002 signals an issue with the efficiency of the Diesel Particulate Filter (DPF), a crucial component in reducing emissions by trapping soot from diesel engines. When the filter’s efficiency falls below the expected threshold, it indicates that the DPF is not functioning as intended, possibly due to blockage, sensor issues, or exhaust leaks. This code is a common challenge across various models and requires thorough diagnostic steps to pinpoint and resolve the underlying causes affecting DPF performance.
P2002 quick overview
| Meaning | P2002: Diesel Particulate Filter Efficiency Below Threshold |
| Is it serious? | Yes, it can lead to reduced vehicle performance, increased emissions, and potentially costly repairs if not addressed promptly. |
| Possible causes | – Clogged or damaged DPF – Faulty DPF sensors – Leaks in the exhaust system – Incorrect Diesel Exhaust Fluid (DEF) quality |
| How to diagnose? | Inspect the DPF and exhaust system for any signs of damage or leaks. Check the DEF quality to ensure it meets the required specifications. Evaluate the DPF sensors for proper operation and accurate readings. Perform a DPF regeneration to clear any soot accumulation if possible. Consult Technical Service Bulletins (TSBs) for any known issues and recommended solutions. |
P2002 Meaning
For those not deeply familiar with diesel engine components, the Diesel Particulate Filter (DPF) plays a vital role in cleaning up exhaust gases by capturing soot particles. The P2002 code indicates that this filter isn’t working as efficiently as it should, which can be due to it being clogged, damaged, or issues with its monitoring sensors.
Addressing this problem often involves checking the filter and its related components, possibly cleaning or replacing the filter, and ensuring the sensors that monitor its performance are in good working order. Regular maintenance and attention to this system help keep the vehicle running cleanly and efficiently.
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How to fix P2002 – learn from mechanics
I looked into P2002 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Ford
Vehicle information 2016 Ford Transit-250 3.2L
Issue + repair history
- Vehicle sets P2002 DPF Efficiency code after approximately 40 miles of driving.
- Replaced DEF fluid, particulate filter, EGR valve, temperature sensors, PM sensor, vapor line assembly.
- PCM re-flash performed.
- DPF and SCR parameters reset.
Other OBD2 Codes + Test Results
- P2002: Particulate Filter Efficiency Below Threshold
Mechanic suggestions
- Check the quality of Diesel Exhaust Fluid (DEF) to ensure it meets specifications.
- Investigate TSB 20-2272, which addresses potential cracks in the diesel particulate filter (DPF) substrate.
- Perform a visual inspection for leaks or damage in the injector system, particularly focusing on Cylinder #3.
- Consider the possibility of additional issues stemming from previously replaced parts, and evaluate their impact on the current problem.
Final fix
- Discovered Injector Cylinder #3 was leaking, causing the efficiency code.
- Replaced the leaking injector.
- Conducted a 75-mile test drive, during which all monitors set without any recurrence of the P2002 code.
Case #2: Nissan
Vehicle information 2008 Nissan Frontier SE 2.5L
Issue + repair history
- Lack of turbo power at take-off from idle or while driving.
- RPM easily reaches 4500.
- Initial scan reveals multiple codes: P2002, P0438, P1622, P1705, P0731.
- Attempted clearing codes and DPF regeneration without success.
- Dealer suggested DPF replacement.
- DPF and two temperature sensors (pre and post) replaced.
- No scan data available for DPF pressure.
- Scoped signal from DPF pressure sensor but uncertain of its status.
- Attempted disconnecting component resembling a catalytic converter between exhaust manifold and DPF without success.
Other OBD2 Codes + Test Results
- P2002: Particulate Matter Over Accumulation
- P0438: Rear Right Exhaust Temperature Sensor Circuit
- P1622: Injector Adjustment Value Unregistered
- P1705: Throttle Position Sensor
- P0731: Automatic Transmission 1st Gear Function
Mechanic suggestions
- Reset DPF data with a scan tool before attempting DPF regeneration.
- Monitor turbo control functionality after addressing DPF code.
- Ensure the use of high-quality oil to prevent rapid DPF blockage.
Final fix
- Following Desmond Downs’s suggestion, reset DPF data, restoring power and clearing warning light.
- Turbo control restored after addressing DPF code.
- Continued monitoring recommended due to the complexity of DPF systems.
Case #3: Volkswagen
Vehicle information 2013 Volkswagen Jetta TDI 2.0L
Issue + repair history
- Car initially came in with only P2002 code, attempted regen and cleared codes which worked temporarily.
- Returned with same code within 2 or 3 days.
- Replaced pressure sensor for P2453 code, which changed pressure readings on PIDS but code returned.
- No reliable spec found for pressure sensor resistance online.
- Questioned whether there is a basic settings or adaptation needed when replacing the sensor.
- Contemplated replacing DPF.
Other OBD2 Codes + Test Results
- P2002: Particulate trap below efficiency
- P2453: DPF pressure sensor implausible signal intermittent
- Forced regen and code clear worked temporarily.
Mechanic suggestions
- Consider cleaning the DPF using a cleaning kit instead of outright replacement.
- Monitor pressure readings at engine off, idle, and 2500RPM to assess sensor performance.
- Verify if regeneration can still be performed and check soot buildup levels.
- Attempt multiple regeneration procedures to ensure accurate readings and acceptable soot levels.
Final fix
- Changed DPF and reset basic settings/readapted, restoring power.
- No further details provided on sensor resistance spec or additional adaptations needed.
How to diagnose P2002
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Brief Explanation |
|---|---|
| Inspect the DPF and exhaust system | Look for physical damage, clogging, or leaks that could impair DPF function. |
| Check the DEF quality | Verify that the Diesel Exhaust Fluid used meets the vehicle’s specifications. |
| Evaluate the DPF sensors | Ensure sensors are providing accurate data on DPF status and soot levels. |
| Perform a DPF regeneration | Attempt to clear soot accumulation through the regeneration process. |
| Consult Technical Service Bulletins | Review any manufacturer advisories for insights into common issues and fixes. |
In the provided service cases, solutions varied from replacing leaky injectors, and resetting DPF data, to outright changing the DPF and its sensors, highlighting the need for a tailored approach based on thorough diagnostics. Properly addressing the P2002 code ensures the longevity and efficiency of the diesel particulate filter system, maintaining vehicle performance and compliance with emission standards.
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko