OBD-II Diagnostic Trouble Code
P246E — Particulate Filter Active/Intrusive Injection Quantity Too Low Bank 1
During an active regen the ECM commanded extra fuel, either through post-injection or a dedicated aftertreatment doser, to heat the DOC. The measured response, usually the DOC temperature rise or doser pressure, showed less fuel was delivered than commanded. The exact monitoring strategy differs by OEM.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Particulate Filter Active/Intrusive Injection Quantity Too Low Bank 1
Code
P246E
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
P246E on the Aftertreatment system is most often aftertreatment doser or 7th injector clogged with carbon — 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 regens that fail or take too long, rising soot load, a DPF lamp, and possible derate. There is usually no smoke, but regens may happen more often.
Common causes
- CommonAftertreatment doser or 7th injector clogged with carbon ($300–$1200)
- OccasionalLow fuel supply pressure to the doser from a restricted filter, a weak lift pump or a failing shutoff valve ($150–$800)
- OccasionalDOC contaminated so the delivered fuel does not produce heat ($1200–$3500)
- OccasionalDoser wiring or valve fault ($100–$600)
How to fix
Check fuel filters and supply pressure to the doser block
When to use: First step
Run the OEM doser flow or purge test and measure the delivered quantity
When to use: To confirm the doser is delivering fuel
Clean or replace the doser nozzle and shutoff valve
When to use: When flow is low
Check DOC exotherm during a parked regen, and replace the DOC if it does not light off
When to use: When fuel delivery is good
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 P246E?
P246E 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 P246E on a commercial truck?
Total repair cost ranges $100–$3500 depending on the root cause. The cheapest fix is usually the first one listed below — Aftertreatment doser or 7th injector clogged with carbon — 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 P246E fail a DOT inspection?
Yes — P246E 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 P246E and related codes?
P246E 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 P246E is set without the companions, the issue is more isolated.
How do I prevent P246E from coming back after a repair?
For P246E (Particulate Filter Active/Intrusive Injection Quantity Too Low 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).