P2405

Evaporative Emission System Leak Detection Pump Sense Circuit Low

P2405 is a generic OBD-II powertrain diagnostic trouble code: Evaporative Emission System Leak Detection Pump Sense 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
P2405
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2405 means

P2405 is stored when the ECM detects that the voltage on the EVAP leak detection pump sense circuit is lower than the expected minimum threshold. This is a companion code to P2404 (range/performance) and P2406 (high), indicating a specific low-voltage or short-to-ground condition on the sense circuit rather than an implausible range.

A low-voltage reading on the sense circuit typically means the signal wire is shorted to ground, the sense element inside the pump is internally shorted, or there is a fault in the ECM input. Because the ECM uses this signal to determine whether the pump has successfully pressurised the EVAP system, a stuck-low signal will prevent successful EVAP leak testing.

The diagnostic approach is to isolate the pump from the harness and check whether the low voltage exists at the harness connector (pointing to a wiring short) or at the pump terminals (indicating an internal pump fault). Resistance checks between the sense pin and chassis ground at the harness side help confirm a wiring short before condemning the pump assembly.

Common causes

Most-frequently reported root causes when P2405 is logged.

  • 1
    Short to ground in the EVAP pump sense signal wiring.
  • 2
    Internally shorted sense element within the EVAP leak detection pump.
  • 3
    Damaged harness chafing against the chassis or exhaust and grounding the sense wire.
  • 4
    Moisture ingress into the pump connector causing a low-resistance path to ground.
  • 5
    Faulty ECM sense input pulled to ground internally.
  • 6
    Incorrect aftermarket or replacement pump with incompatible sense circuit.

Symptoms drivers notice

MIL illuminated.
EVAP monitor unable to complete.
Possible mild fuel vapour odour if a real EVAP leak is also present.
No engine performance or driveability effects.

How to diagnose P2405

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool and document all DTCs and freeze-frame data.
  2. 2
    Inspect the EVAP pump wiring harness and connector for chafing, moisture, or visible shorts.
  3. 3
    With the pump connector disconnected, measure voltage on the sense circuit at the harness side.
  4. 4
    Check resistance between the sense pin and chassis ground at the harness connector to locate a short.
  5. 5
    Measure resistance of the sense circuit at the pump connector to check for an internal short.
  6. 6
    Repair any wiring short found; if wiring is clean, replace the EVAP leak detection pump assembly.
  7. 7
    Clear DTCs and run the EVAP monitor to confirm the repair.

Vehicles where we've handled P2405

Platforms in our catalogue with confirmed P2405 coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

What is the difference between P2404 and P2405?

P2404 indicates the sense signal is out of the expected range or performing implausibly, while P2405 specifically identifies a low-voltage (short to ground) condition on the same circuit.

Can I repair the wiring myself?

If you can locate and access the shorted section of harness and have basic wiring repair skills, yes; however, confirm the short location before cutting into the harness.

Will P2405 affect fuel economy?

No. EVAP monitor faults relate to emissions control and do not affect combustion efficiency or fuel consumption directly.

How long can I drive with P2405?

The vehicle will run normally from a performance standpoint, but an active MIL will fail an OBD-II emissions test; repair should be made before the next inspection.

Disabling P2405 in software

RaceTune can permanently disable P2405 — 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 P2405 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
  • Bosch EDC17CP09 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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