03/07/2026 6:12 am
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Automotive Q&A
DPF differential pressure is 3.2 kPa at idle and 18 kPa at 2,500 rpm
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A 2017 Ram 6.7 reports frequent regeneration requests. Differential pressure is 0.4 kPa key-on engine-off, 3.2 kPa at hot idle and 18 kPa at 2,500 rpm with no load. Calculated soot is moderate, but the pressure rises faster than expected. Both hoses look connected and there are no exhaust leaks ahead of the filter.
How can I tell whether this is true filter restriction or a biased sensor or hose?
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04/07/2026 6:49 am
Start with the key-off zero and compare the scan value to a known pressure source if the service procedure permits. Remove both sensor hoses and inspect them for soot, moisture, soft spots and restrictions; a plugged low-pressure hose can create a falsely high differential. Measure actual pressure at the filter ports with a suitable manometer if necessary.
Only judge DPF loading after the sensing path is proven. Compare measured restriction with calculated soot and ash history, and verify exhaust temperature data before any regeneration. A forced regen is not a diagnostic substitute and should not be run when restriction or safety prerequisites are unresolved.
Topic starter
05/07/2026 9:43 am
The downstream reference hose passed air but was restricted by a hard soot plug at the metal nipple. Cleaning the approved sensing passage and renewing the hose produced 0.0 kPa KOEO, 0.8 kPa at idle and 5.6 kPa at 2,500 rpm. Regeneration frequency returned to normal.