P260C

Reductant Pump Control Circuit Low

P260C is a generic OBD-II powertrain diagnostic trouble code: Reductant Pump Control Circuit Low. 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.

Code
P260C
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P260C means

P260C is stored when the ECM/PCM detects that the reductant pump control circuit is exhibiting a voltage or signal level that is lower than expected, indicating a short to ground condition. The ECM monitors the pump command line and expects a specific voltage state when the pump is commanded on or off; a persistently low voltage when the circuit should be high indicates an unwanted ground path exists.

A short to ground in the pump control wiring pulls the circuit voltage down, which the ECM interprets as a circuit-low fault. This condition typically causes the pump driver or relay to detect an abnormal state and may result in the pump being disabled by the ECM to protect the driver from sustained overcurrent. Unlike an open circuit, a short to ground can allow partial or no pump operation depending on where in the circuit the fault exists.

Diagnosis focuses on finding the unintended ground path in the wiring harness between the ECM and the pump module or relay. Heat damage, chafing against the chassis or exhaust, and connector corrosion are the most frequent physical causes.

Common causes

Most-frequently reported root causes when P260C is logged.

  • 1
    Wiring harness chafed against the vehicle chassis or exhaust creating a short to ground.
  • 2
    Crushed or pinched pump control wire with insulation breach.
  • 3
    Corroded connector with a conductive bridge between the signal pin and a ground pin.
  • 4
    Faulty reductant pump module with an internally grounded control input.
  • 5
    Water ingress into the pump connector shorting control lines to the module housing.
  • 6
    Incorrect routing of the pump harness after a previous repair.
  • 7
    ECM internal fault causing the output driver to pull low continuously.

Symptoms drivers notice

MIL illuminated with P260C stored.
Reductant or SCR system fault warning on the instrument cluster.
Reductant pump may not operate or may operate erratically.
SCR dosing inactive or unreliable.
Possible companion open-circuit code if the fault is intermittent.

How to diagnose P260C

A typical diagnostic flow when this code is present.

  1. 1
    Read all DTCs and freeze-frame data, noting any companion circuit or dosing system codes.
  2. 2
    Disconnect the reductant pump module connector and measure voltage on the control wire with the ignition on; a voltage near ground confirms a short to ground in the harness.
  3. 3
    Visually inspect the pump control wiring harness for chafing, crushing, or heat damage, particularly near exhaust or chassis contact points.
  4. 4
    Check the connector for moisture intrusion, corrosion, or bridging between pins.
  5. 5
    If the harness is clear, check continuity from the control wire to chassis ground with the pump disconnected to isolate whether the short is in the harness or the pump module.
  6. 6
    If the short is in the pump module, replace the pump module; if in the harness, repair or replace the damaged section.
  7. 7
    Clear codes and verify repair with a drive cycle, monitoring pump operation and pressure via scan tool.

Vehicles where we've handled P260C

Platforms in our catalogue with confirmed P260C coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

What is the difference between P260A and P260C?

P260A is an open-circuit fault where the circuit is broken, while P260C is a short-to-ground fault where the circuit has an unintended path to ground. They require different diagnostic approaches.

Can a short to ground damage the ECM?

ECMs have driver protection circuitry, but a prolonged hard short can stress the output driver. Diagnose and repair the short promptly to reduce risk to the ECM.

If the pump harness looks fine visually, where else should I check?

Check inside the pump module connector carefully for pin-to-pin bridging, and verify the internal resistance of the pump module control input is within specification after disconnecting the harness.

Can P260C set during normal operation or only at startup?

P260C can set any time the ECM commands the pump and detects a circuit-low condition. It may be most apparent during cold starts when the pump is first energized.

Disabling P260C in software

RaceTune can permanently disable P260C — 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.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECUs with a P260C 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.

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