Category
Powertrain → Aftertreatment / DPF System
What it means (plain English)
The ECM sees the DPF pressure sensor “B” signal voltage lower than expected. This often means the sensor is stuck reading near zero, or there’s an electrical issue pulling the signal low.
Symptoms
- MIL on
- Regen disabled or failing
- Possible derate/limp mode
- Excess soot buildup
- Engine may run normally until soot overload forces limp
Priority Level
High — regen logic depends on this sensor.
Common Causes
- Short-to-ground in signal circuit
- Open 5V reference or signal return
- Failed pressure sensor “B”
- Disconnected or cracked sensor tubing
How Pros Diagnose It
- KOEO check — sensor should read ~0 PSI; if stuck low, suspect fault.
- Voltage test — check reference, ground, and signal.
- Inspect hoses — disconnected or frozen lines mimic “low” signal.
- Compare to sensor “A” readings.
Likely Fixes
- Replace sensor “B”
- Repair harness short-to-ground
- Replace hoses/tubes
- Clean connector corrosion
Related/Companion Codes
- P2462 — Circuit Malfunction
- P2465 — Circuit High
- P2452–P2455 (Sensor A group)
Tech Notes
- Ford 6.7L: wiring rub-through near turbo common.
- Duramax LML: condensation in hoses can freeze and trigger “low” codes.
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