Loss of the Diesel Particulate Filter (DPF) Pressure Sensor Signal
The DPF pressure sensor is reporting a loss of signal.
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What it means (plain English)
The DPF pressure sensor measures the pressure before and after the DPF to monitor its efficiency. If it loses signal, the computer can’t tell if the filter is clogged, leading to potential performance issues.
What the computer is actually seeing
The DPF pressure sensor should produce a voltage signal between 0.5V to 4.5V based on the pressure difference. A loss of signal typically shows as a constant 0V or a voltage outside the normal range.
What a healthy reading looks like
Pressure differential should be around 0-15 psi, translating to an appropriate voltage signal from the sensor.
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.
- 11. Inspect the wiring and connectors for the DPF pressure sensor: Look for breaks, corrosion, or loose connections.
- 22. Check the DPF pressure sensor voltage while the engine is running. You should see a voltage response between 0.5V to 4.5V. If you don't, replace the sensor.
- 33. If the sensor seems fine, perform a back pressure test on the DPF using a manometer. Check for excessive back pressure, which should be below 15 psi.
- 44. If back pressure is normal, check the Engine Control Module (ECM) for faults and update the software if necessary.
- 55. If all checks are good, consider further diagnosis of the exhaust system for blockages or pinches.
Common causes
- Broken or corroded wiring to the sensor
- Faulty DPF pressure sensor
- Moisture or debris in the sensor connector
- Exhaust back pressure issues
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not ideal. Drivability might be affected, and you could risk damage to the DPF if it's truly clogged.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will likely return.
Why is this code paired with others like SPN 4044?
These codes often appear together because they relate to the same sensor and its operation in the DPF monitoring system.
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