OBD-II Diagnostic Trouble Code
P244C — Exhaust Gas Temperature Too Low Bank 1
During a regen, or when the ECM needed elevated exhaust temperature, the measured exhaust gas temperature on bank 1 stayed below the target. This is usually seen at the DOC inlet or outlet or the DPF inlet. It means the regen could not reach the heat it needs to burn soot.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Exhaust Gas Temperature Too Low Bank 1
Code
P244C
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
P244C on the Aftertreatment system is most often faulty or contaminated doc that is not lighting off the dosed fuel — 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 take too long or abort, rising soot load, frequent regen requests and DPF lamp warnings. A derate may follow if the DPF loads up. Some trucks also produce white smoke during regen attempts because of unburned dosing fuel.
Common causes
- CommonFaulty or contaminated DOC that is not lighting off the dosed fuel ($1200–$3500)
- CommonAftertreatment (7th) fuel injector or doser plugged or not delivering fuel ($300–$1200)
- OccasionalExhaust leak or missing insulation lowering exhaust temperature ($150–$700)
- OccasionalExhaust temperature sensor reading low ($120–$400)
- OccasionalLight-load duty cycle or low ambient temperature preventing heat buildup ($0–$200)
How to fix
Watch DOC inlet and outlet temperatures during a parked regen; the outlet should rise well above the inlet once dosing starts
When to use: First step, to decide between the DOC, the doser and the sensors
Test the aftertreatment doser or 7th injector for flow and clean or replace it
When to use: When DOC temperatures do not rise during dosing
Compare all exhaust temperature sensors at cold soak and replace any that disagree
When to use: When one sensor reads differently from the others
Replace the DOC if it is face-plugged or poisoned
When to use: When fuel is delivered but no exotherm occurs
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
- → P244D — Exhaust Gas Temperature Too High Bank 1
- → P245A — EGR Cooler Bypass Control Circuit/Open
- → P246E — Particulate Filter Active/Intrusive Injection Quantity Too Low Bank 1
Frequently Asked Questions
Can I drive with code P244C?
P244C 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 P244C on a commercial truck?
Total repair cost ranges varies depending on the root cause. The cheapest fix is usually the first one listed below — Faulty or contaminated DOC that is not lighting off the dosed fuel — 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 P244C fail a DOT inspection?
Yes — P244C 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 P244C and related codes?
P244C is closely related to: P244A (Diesel Particulate Filter Differential Pressure Too Low), P244B (Diesel Particulate Filter Differential Pressure Too High), P244D (Exhaust Gas Temperature Too High Bank 1), P245A (EGR Cooler Bypass Control Circuit/Open). 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 P244C is set without the companions, the issue is more isolated.
How do I prevent P244C from coming back after a repair?
For P244C (Exhaust Gas Temperature 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).