Diesel Particulate Filter Differential Pressure High
Indicates high differential pressure across the diesel particulate filter (DPF).
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The DPF collects soot from the exhaust gases. When it gets too full, it can’t filter properly, leading to high pressure readings across the filter.
What the computer is actually seeing
The engine control module (ECM) monitors the pressure before and after the DPF. A difference of over 5 inches of water column (inH2O) indicates a problem.
What a healthy reading looks like
Pressure differential should be below 5 inH2O during normal operation.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check for exhaust leaks near the DPF and upstream sensors.
- 2Inspect DPF for obvious physical damage or signs of soot accumulation.
- 3Test differential pressure sensor voltage and ground integrity; should be near 0.5V at idle and increase with RPM.
- 4If differential pressure exceeds 5 inH2O at idle, initiate regeneration; monitor to see if values decrease post-regeneration.
- 5If pressure stays high after regeneration and sensor checks out, consider replacing DPF or inspecting for upstream restrictions.
Common causes
- Clogged DPF
- Faulty pressure sensors
- Exhaust leaks
- Failed active regeneration process
- Intake restrictions
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
It's best to avoid driving until resolved, as it can lead to reduced power and potential engine damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will return.
Why does this code link with DPF regeneration issues?
High pressure often means the DPF is too full to self-clean properly, preventing effective regeneration.
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