P260A
Control Circuit /OpenP260A is a generic OBD-II powertrain diagnostic trouble code: Control Circuit /Open. 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 P260A means
P260A is set when the ECM/PCM detects an open circuit or loss of continuity in the control circuit for the reductant supply pump. The reductant pump is electrically driven and controlled by the ECM via a relay, dedicated driver, or direct H-bridge output depending on system design. An open-circuit condition means the ECM cannot complete the command path to energize the pump.
Without a functioning pump command circuit, the pump will not operate regardless of demand from the SCR dosing strategy. The ECM detects the open by monitoring circuit feedback, such as a voltage sense line or current return path, and finding no evidence of pump energization. This is a hard fault typically caused by a broken wire, open relay coil, or detached connector.
Loss of the reductant pump prevents all DEF delivery to the SCR catalyst. This will result in zero NOx conversion and will quickly accumulate NOx-related faults. On emissions-regulated vehicles this can trigger a derate after a defined number of non-compliant drive cycles.
Common causes
Most-frequently reported root causes when P260A is logged.
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1
Broken or disconnected wire in the pump control circuit.
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2
Open relay coil in the reductant pump relay.
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3
Blown fuse in the pump supply or control circuit.
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4
Detached or poorly seated connector at the pump module or relay.
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5
Corroded connector pins creating high resistance approaching an open.
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6
Faulty ECM output driver with an internal open on the pump command pin.
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7
Damaged wiring harness due to heat, chafing, or rodent damage near the pump.
Symptoms drivers notice
How to diagnose P260A
A typical diagnostic flow when this code is present.
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1
Read all DTCs and record any companion pump, pressure, or dosing system codes.
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2
Inspect the reductant pump relay and fuse; replace if open or blown.
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3
Visually trace the pump wiring harness for broken, chafed, or disconnected sections.
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4
Check for supply voltage at the pump module connector with the ignition on and pump commanded on.
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5
Measure continuity of the pump control wire from the relay or ECM to the pump connector.
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6
Inspect the pump module connector for pushed-back terminals or corrosion.
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7
If power and circuit continuity are confirmed at the pump but it does not run, the pump motor itself may be open and require pump module replacement.
Vehicles where we've handled P260A
Platforms in our catalogue with confirmed P260A coverage.
Related powertrain codes
Frequently asked questions
Will the pump run at all with P260A?
No. An open-circuit fault means the electrical command path is broken and the pump cannot receive power through the normal control circuit.
Can a blown fuse cause P260A?
Yes. A blown fuse in the pump supply circuit creates an open circuit that the ECM will detect as P260A. Always check the fuse before tracing wiring.
How do I confirm the relay is the fault?
Swap the reductant pump relay with a known-good relay of the same type, or bench-test the suspect relay by applying 12V to the coil terminals and checking for continuity across the switching contacts.
Is P260A different from P260C?
P260A indicates an open-circuit condition while P260C indicates a low-circuit condition (short to ground). They share the same circuit but represent different fault types requiring different diagnostic paths.
Disabling P260A in software
RaceTune can permanently disable P260A — 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 P260A 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 EDC17C50 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.
Got P260A in your scan?
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