OBD-II Diagnostic Trouble Code
P246F — Particulate Filter Active/Intrusive Injection Quantity Too High Bank 1
The ECM detected more regen fuel being delivered than commanded, usually from an excessive DOC temperature rise or a doser pressure that does not hold. This typically means the doser or 7th injector is leaking or stuck open. Excess fuel can overheat the DOC and DPF.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Particulate Filter Active/Intrusive Injection Quantity Too High Bank 1
Code
P246F
Category
Powertrain
Subsystem
Aftertreatment
Truck-relevant
Yes
What this means for truckers
Service within a few days on a Cummins X15, Detroit DD15, PACCAR MX-13. Performance is likely degraded. Continuing to drive without service risks additional component damage.
Before you replace parts — try this first
P246F on the Aftertreatment system is most often doser or 7th injector nozzle leaking or stuck open — 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
Expect high exhaust temperatures, white smoke or a raw fuel smell, high-temperature codes, and possible DPF damage. Fuel consumption is higher, and derate or a regen inhibit may follow.
Common causes
- CommonDoser or 7th injector nozzle leaking or stuck open ($300–$1200)
- OccasionalDoser shutoff valve leaking ($200–$700)
- OccasionalEngine injector leaking during post-injection ($600–$3000)
- RareFaulty temperature or pressure sensor misreporting ($120–$400)
How to fix
Run the OEM doser leak test and inspect the DOC face for raw fuel
When to use: First step
Replace the leaking doser nozzle or shutoff valve
When to use: When the leak test fails
Perform injector leakdown or contribution tests
When to use: When the doser tests good but fuel is still present
Inspect the DPF for damage after overtemperature events
When to use: After high-temperature conditions
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P244A — Diesel Particulate Filter Differential Pressure Too Low
- → P244B — Diesel Particulate Filter Differential Pressure Too High
- → P244C — Exhaust Gas Temperature Too Low Bank 1
- → P244D — Exhaust Gas Temperature Too High Bank 1
- → P245A — EGR Cooler Bypass Control Circuit/Open
Frequently Asked Questions
Can I drive with code P246F?
P246F is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix P246F on a commercial truck?
Total repair cost ranges $120–$3000 depending on the root cause. The cheapest fix is usually the first one listed below — Doser or 7th injector nozzle leaking or stuck open — 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 P246F fail a DOT inspection?
Yes — P246F 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 P246F and related codes?
P246F is closely related to: P244A (Diesel Particulate Filter Differential Pressure Too Low), P244B (Diesel Particulate Filter Differential Pressure Too High), P244C (Exhaust Gas Temperature Too Low Bank 1), P244D (Exhaust Gas Temperature Too High Bank 1). 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 P246F is set without the companions, the issue is more isolated.
How do I prevent P246F from coming back after a repair?
For P246F (Particulate Filter Active/Intrusive Injection Quantity Too High 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).