OBD-II Diagnostic Trouble Code
P2002 — Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
P2002 means DPF efficiency is below threshold on bank 1. The ECM, using the differential pressure sensor or a soot sensor, sees that the filter is not trapping soot properly, usually because it is cracked, melted or removed.
Severity 4/5
Truck-relevant
Stop within 50 mi
Severity
Stop within 50 mi
Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
Code
P2002
Category
Powertrain
Subsystem
Aftertreatment
Truck-relevant
Yes
What this means for truckers
P2002 (DPF Efficiency Below Threshold, Bank 1) means your Diesel Particulate Filter isn't capturing soot like it should — or the sensors think it isn't. On 2010+ commercial trucks this is the second-most common emissions code (after P204F). Two paths: (1) Forced/parked regen first — sometimes the DPF is just loaded and needs to burn off. Cost: $250-450 at a truck shop. (2) If forced regen doesn't clear it, the DPF needs cleaning (ash blowout, $400-650) or replacement ($2,400-5,500 depending on truck). DPF replacement at 600K+ miles is normal wear. Don't let a P2002 sit — continued driving without regen completing causes derate to limp mode within ~50 hours.
Before you replace parts — try this first
P2002 on the Aftertreatment system is most often cracked or melted dpf — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Black soot at the tailpipe, check-engine light, possible derate, and low DPF differential pressure readings. Regens may happen less often than normal.
Common causes
- CommonCracked or melted DPF ($2000–$7000)
- CommonFaulty DPF differential pressure sensor ($200–$600)
- OccasionalCracked or disconnected pressure sensor hoses ($80–$300)
- OccasionalExhaust leak around the DPF ($150–$600)
- RareFaulty soot sensor (if fitted) ($300–$900)
How to fix
Check differential pressure readings and sensor hoses
When to use: First step
Inspect the DPF outlet and downstream pipe for soot
When to use: To confirm DPF failure
Replace the pressure sensor or hoses
When to use: When the sensor or hoses are bad
Replace the DPF and find the root cause of melting, such as excess soot from injector, EGR or turbo faults
When to use: When the DPF is cracked or melted
Affects most
- Ford F-3501 complaint mention this code
- RAM 35001 complaint mention this code
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P2003 — Diesel Particulate Filter Efficiency Below Threshold (Bank 2)
- → P2031 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2
- → P2032 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2 Low
- → P2033 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2 High
- → P2080 — Exhaust Gas Temperature Sensor Circuit Range/Performance Bank 1 Sensor 1
- → Complaints on Ford F-350
- → Complaints on RAM 3500
Frequently Asked Questions
Can I drive with code P2002?
Drive with caution. P2002 is severity 4 — stop within ~50 miles. Most commercial diesel codes at this severity (turbo, fuel rail, transmission solenoid) can damage adjacent expensive components if left unrepaired. Get to a service location before highway-speed loads.
How much does it cost to fix P2002 on a commercial truck?
Total repair cost ranges $80–$7000 depending on the root cause. The cheapest fix is usually the first one listed below — Cracked or melted DPF — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P2002 fail a DOT inspection?
Yes — P2002 is an emissions-related code, and DOT inspectors check emissions compliance. An active emissions code with a check engine light can result in an out-of-service violation under FMCSA Part 393. The truck typically can't be moved until the code is cleared. Repeated emissions violations escalate to CSA scores.
What's the difference between P2002 and related codes?
P2002 is closely related to: P2003 (Diesel Particulate Filter Efficiency Below Threshold (Bank 2)), P2031 (Exhaust Gas Temperature Sensor Bank 1 Sensor 2), P2032 (Exhaust Gas Temperature Sensor Bank 1 Sensor 2 Low), P2033 (Exhaust Gas Temperature Sensor Bank 1 Sensor 2 High). These codes share the same subsystem (aftertreatment) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P2002 is set without the companions, the issue is more isolated.
How do I prevent P2002 from coming back after a repair?
For P2002 (Diesel Particulate Filter Efficiency Below Threshold (Bank 1)), prevention centers on the aftertreatment system. Run quality DEF (verify supplier — BlueDEF, PEAK, Yara Air1). Don't skip parked regens — when the dash asks for one, do it. Avoid extended idle time which fouls the DPF. Replace NOx sensors at the OEM interval (typically 400K miles).