P280D
Reductant Pump PerformanceP280D is a generic OBD-II powertrain diagnostic trouble code: Reductant Pump Performance. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.
What P280D means
P280D is stored when the reductant pump is electrically commanded but fails to deliver the expected DEF flow or pressure. Unlike circuit-high or circuit-low faults that indicate a wiring or driver issue, P280D is a performance or rationality fault: the pump receives its commanded drive signal but the system cannot confirm adequate fluid delivery through pressure, flow, or dosing feedback sensors.
Common causes include a worn or cavitating pump that can no longer develop adequate pressure, a blocked filter or strainer restricting suction, an air lock in the DEF supply line, or a DEF level low enough that the pump inlet is partially exposed. Crystallized DEF in the pump body or connecting hoses can also obstruct flow without triggering a simple circuit fault.
The MIL is illuminated and, without sufficient DEF delivery, the SCR system will be unable to maintain NOx conversion efficiency. A derate is likely to follow if the performance fault persists across qualifying drive cycles. Checking DEF level, inspecting the filter, and performing a priming cycle are appropriate first steps before condemning the pump assembly.
Common causes
Most-frequently reported root causes when P280D is logged.
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1
Worn reductant pump no longer capable of developing adequate pressure or flow.
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2
Blocked pump inlet filter or strainer restricting DEF suction.
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3
Air lock in the DEF suction line preventing the pump from priming.
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4
Very low DEF level causing the pump inlet to draw air.
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5
Crystallized DEF in the pump body or supply line partially blocking flow.
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6
Kinked or collapsed DEF supply hose reducing inlet flow.
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7
Failed check valve in the DEF circuit allowing pressure bleed-down between cycles.
Symptoms drivers notice
How to diagnose P280D
A typical diagnostic flow when this code is present.
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1
Check DEF level first; if low, top up with certified fluid and re-evaluate.
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2
Read all DTCs and check for companion circuit, injector, or SCR efficiency codes.
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3
Perform a DEF system prime and pressure test using the scan tool functional test mode.
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4
Inspect the DEF supply line and filter for kinks, blockages, or crystallized deposits.
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5
Check the pump inlet strainer inside the DEF tank module for contamination or clogging.
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6
Monitor live system pressure during a commanded pump cycle and compare to specification.
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7
If pressure remains low with clear lines and adequate fluid, replace the reductant pump assembly.
Vehicles where we've handled P280D
Platforms in our catalogue with confirmed P280D coverage.
Related powertrain codes
Frequently asked questions
Does P280D mean the pump has failed?
Not necessarily. A blocked filter, low DEF level, or air lock can cause the same performance symptom. Rule those out before replacing the pump.
Can crystallized DEF cause P280D?
Yes. DEF crystals forming in the pump, lines, or filter can restrict flow enough to set a performance fault without causing an electrical circuit code.
How is P280D different from a circuit-low or circuit-high pump fault?
Circuit faults indicate an electrical problem with the driver or wiring. P280D means the electrical signal is correct but fluid delivery performance is inadequate.
Will adding more DEF resolve P280D?
If low fluid level was the cause, yes. If the pump, filter, or lines are the issue, refilling alone will not resolve it.
Disabling P280D in software
RaceTune can permanently disable P280D — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.
ECUs with a P280D disable in our catalogue
Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.
- Bosch EDC17C56 verified 1 software version
- Bosch MD1CP002 verified 1 software version
- Bosch MD1CS001 verified 1 software version
Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.
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