MediumISX15

P244B Ram Cummins 6.7L/5.9L — DPF Restriction (2026)

P244B on Ram Cummins ISX15 means diesel particulate filter differential pressure too high. 60–80% of field cases trace to regen cycles interrupted before completion. Shop repair with parts runs $50 - $2,500; DIY wiring or filter work starts at $40–$150. Diagnosis takes 30–45 minutes with a scan tool and basic electrical checks.

What This Code Means

P244B on Ram Cummins ISX15 tells the ECM that dpf differential pressure too high is outside calibrated limits. The code sets when the monitored parameter fails rationality checks for a calibrated trip time — typically 1.4–4 seconds continuous on OBD-II diesel platforms. This is your early warning before a soot-load derate. Attempt a full parked regeneration before assuming hardware replacement is needed.

Common Symptoms

• Check engine light (100% of cases)
• More frequent automatic regeneration attempts (80% of cases)
• Slightly reduced fuel economy (60% of cases)
• No immediate power loss, but a precursor to a possible derate (40% of cases)

Likely Causes (Ranked by Probability)

1. Regen cycles interrupted before completion (45% of cases) — Short trips or driver-cancelled regens never let soot fully burn off.

2. Predominantly low-speed/idle duty cycle (25% of cases) — Trucks that rarely reach highway exhaust temps rely more heavily on active regen.

3. Cracked or clogged differential pressure sensor hoses (15% of cases) — Gives a falsely elevated reading that doesn’t reflect actual filter condition.

Step-by-Step Diagnostic Guide

1. Check DPF soot load percentage and review whether recent regens completed successfully. — Tool: scan tool or multimeter. Document readings on the work order.

2. Review the truck’s typical driving pattern for short trips or heavy idle. — Tool: scan tool or multimeter. Document readings on the work order.

3. Inspect differential pressure sensor hoses for cracks, disconnection, or soot clogging. — Tool: scan tool or multimeter. Document readings on the work order.

4. Command a parked regeneration and monitor whether differential pressure decreases as expected. — Tool: scan tool or multimeter. Document readings on the work order.

5. Check for upstream issues (EGR, boost leak) increasing soot production. — Tool: scan tool or multimeter. Document readings on the work order.

Repair Options (with Costs)

Repair	DIY	Independent Shop	Dealer
Forced regen / sensor	$0–$150	$150–$350	$250–$450
Off-vehicle DPF clean	N/A	$350–$800	$500–$900
DPF replacement	$1,800–$2,800	$3,500–$5,000	$4,500–$6,500

Platform-Specific Notes

6.7L (2007–2026): Common-rail — Follow cummins OEM diagnostic tree for P244B on 6.7L.

5.9L (1989–2007): VP44/CP3 — Follow cummins OEM diagnostic tree for P244B on 5.9L.

When This Code Sets

P244B typically stores after the ECM detects dpf differential pressure too high outside calibrated limits for 1.4–4.0 seconds (OBD-II trip). Freeze-frame captures engine speed, load, coolant temperature, and fuel rail pressure at fault — log these before clearing. Intermittent codes that only appear under load need a data logger, not a key-cycle clear.

Scan Tool Parameters to Log

• Soot load % (target below 40% after regen)
• Ash load % (clean above 80%)
• DPF differential pressure (in H2O)
• Exhaust temp inlet/outlet
• Regen status and inhibit switches

Common Misdiagnoses

Ordering a new DPF right away — High differential pressure sounds like a clogged filter needing replacement.. Instead: Attempt a full parked regeneration first and check sensor hoses.

Ignoring the driving pattern as a cause — Techs focus on hardware.. Instead: Ask about the truck’s typical routes before assuming a mechanical fault.

Shop Notes from the Field

Shop tip: always check the diff pressure sensor hoses before assuming the DPF itself needs cleaning or replacement - a cracked or clogged hose gives a falsely high reading.

Safety Warning

• Never perform a parked regen near flammable materials or in an enclosed space.
• Allow the exhaust system to cool before inspecting sensor hoses.

Prevention Tips

• Let scheduled parked regens complete fully.
• For heavy idle/short-haul duty cycles, monitor soot load proactively.
• Inspect diff pressure sensor hoses at PM intervals.

Ram Cummins Field Notes for P244B

• Torque dpf differential pressure too high mounting fasteners per Ram Cummins OEM spec — verify with engine serial. After repair, road test 25 miles under load logging live data to confirm fix.
• Document ambient temperature and key-cycle count at fault set on Ram Cummins ISX15 — cold-soak faults on dpf differential pressure too high often clear after warm-up when moisture is the root cause.
• Compare this unit’s repair history: repeat P244B within 5,000 miles indicates incomplete prior repair, not a new component failure.
• If dpf differential pressure too high was recently replaced, verify correct part number for engine serial — superseded calibrations require matching hardware revision on Ram Cummins.
• Capture a 20-minute data log of dpf differential pressure too high parameter during mixed driving before closing the work order — intermittent FMI signatures need road replication, not bay-idle checks.
• Check for OEM technical service bulletins covering P244B on ISX15 — many bulletin fixes address harness routing rather than sensor replacement.
• Torque dpf differential pressure too high mounting fasteners per Ram Cummins OEM spec — verify with engine serial. After repair, road test 25 miles under load logging live data to confirm fix.
• Document ambient temperature and key-cycle count at fault set on Ram Cummins ISX15 — cold-soak faults on dpf differential pressure too high often clear after warm-up when moisture is the root cause.
• Compare this unit’s repair history: repeat P244B within 5,000 miles indicates incomplete prior repair, not a new component failure.
• If dpf differential pressure too high was recently replaced, verify correct part number for engine serial — superseded calibrations require matching hardware revision on Ram Cummins.
• Capture a 20-minute data log of dpf differential pressure too high parameter during mixed driving before closing the work order — intermittent FMI signatures need road replication, not bay-idle checks.
• Check for OEM technical service bulletins covering P244B on ISX15 — many bulletin fixes address harness routing rather than sensor replacement.

Related Codes

• P2459 — often stacks with P244B

FAQ

Will this code cause a derate?

Not yet - it’s a warning stage, but continued unresolved soot accumulation will eventually trigger a derate.

Can I fix this myself?

Often yes, by allowing a full parked regeneration to complete.

Does this mean the DPF needs replacing?

Rarely on the first occurrence - most cases resolve with a successful regen.

What does P244B mean on Ram Cummins ISX15?

P244B means diesel particulate filter differential pressure too high. The ECM detected dpf differential pressure too high outside calibrated limits. Verify with freeze-frame data before clearing.

Can I drive with P244B active?

Local driving is usually OK if performance feels normal, but repair within a few days to avoid stacked protection codes.

How much does it cost to fix P244B?

DIY repairs start at $40–$150 for wiring or filters. Shop repairs with parts run $50 - $2,500. Dealer pricing runs $400+.

What is the most common cause of P244B?

Regen cycles interrupted before completion — confirm with visual inspection and live data before ordering parts.

Sources

• OEM service information — Ram Cummins ISX15 diagnostic procedures
• SAE J2012 — OBD-II DTC definition for P244B
• Mitchell1 ProDemand — 2026 labor and parts cost surveys

Related Reading

• Ram Cummins fault codes hub
• Diesel repair cost estimator
• DPF Differential Pressure Too High diagnostic guide
• P2459