P258F
Reductant Pump Speed Sensor CircuitP258F is a generic OBD-II powertrain diagnostic trouble code: Reductant Pump Speed Sensor Circuit. 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 P258F means
P258F indicates that the ECM/PCM has detected a fault in the speed sensor circuit associated with the reductant supply pump. Many modern reductant pump modules incorporate an internal speed or rotation sensor that provides feedback to the ECM confirming the pump impeller is rotating at the commanded rate. This closed-loop feedback allows the system to detect pump stall, cavitation, or mechanical seizure.
When the ECM commands the pump to operate and does not receive valid speed sensor feedback within the expected range or timing, it logs P258F. The fault can be triggered by an open or shorted signal wire, a failed speed sensor inside the pump module, or contamination preventing the sensor from reading the rotating target.
Because this code indicates loss of pump feedback, the ECM cannot confirm accurate DEF delivery and may disable or limit SCR dosing to prevent over-injection. The root cause is most often the reductant pump module itself, as the speed sensor is typically integrated and not serviceable separately.
Common causes
Most-frequently reported root causes when P258F is logged.
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1
Integrated speed sensor inside the reductant pump module has failed.
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2
Open or shorted wiring in the pump speed sensor signal circuit.
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3
Corroded or damaged connector at the pump module or ECM.
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4
DEF contamination inside the pump module affecting sensor operation.
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5
Mechanical seizure of the pump impeller preventing rotation.
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6
Electrical noise or interference corrupting the speed sensor signal.
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7
ECM internal fault in the speed sensor input processing circuit.
Symptoms drivers notice
How to diagnose P258F
A typical diagnostic flow when this code is present.
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1
Read all DTCs and note any companion reductant pressure, flow, or pump circuit codes.
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2
Inspect the wiring harness and connector at the reductant pump for damage, corrosion, or loose pins.
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3
With the pump commanded on via scan tool, monitor the pump speed PID to confirm whether any signal is present.
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4
Measure signal circuit continuity from the pump connector to the ECM with the harness disconnected.
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5
Check for shorts to ground and shorts to voltage on the speed sensor signal wire.
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6
If wiring checks pass and the pump motor runs but no speed signal is produced, the pump module speed sensor has failed.
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7
Replace the reductant pump module as an assembly if the internal sensor is confirmed faulty.
Related powertrain codes
Frequently asked questions
Can I replace just the speed sensor, or must I replace the whole pump?
On most vehicles the speed sensor is integrated into the pump module and is not separately serviceable. Full pump module replacement is typically required.
Will the SCR system still dose with P258F active?
The ECM may disable or limit dosing because it cannot confirm pump rotation. This protects the catalyst from over-injection or under-injection events.
Can DEF crystallization cause P258F?
Yes. Heavy crystallization inside the pump module can mechanically impede impeller rotation, preventing the speed sensor from generating a signal.
Is P258F a common failure on high-mileage vehicles?
Pump module wear and DEF-related corrosion are known contributors to speed sensor failures on vehicles with extended mileage or infrequent DEF maintenance.
Disabling P258F in software
RaceTune can permanently disable P258F — 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.
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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