P2409

Leak Detection Pump Control Circuit High

P2409 is a generic OBD-II powertrain diagnostic trouble code: Leak Detection Pump Control Circuit High. 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
P2409
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2409 means

P2409 is set when the powertrain control module (PCM) detects an unexpectedly high voltage on the control circuit of the evaporative emission (EVAP) leak detection pump. The leak detection pump is used to pressurize or draw a vacuum on the fuel tank and EVAP system so that the PCM can identify leaks as small as 0.020 inches in diameter.

A high circuit condition typically points to a short to voltage on the signal or control wire, an open in the low-side driver circuit, or an internal fault in the pump relay or solenoid. The PCM monitors the actual circuit state against the commanded state; when the circuit reads high while the pump is commanded off, the fault is logged.

Although the vehicle usually remains driveable with this code set, the EVAP system will not complete its self-test, which means other EVAP faults may go undetected and the emissions readiness monitor will not set to ready. Repair should be prioritized to restore full emissions compliance.

Common causes

Most-frequently reported root causes when P2409 is logged.

  • 1
    Short to voltage in the leak detection pump control wiring harness.
  • 2
    Faulty leak detection pump solenoid with internal winding short.
  • 3
    Defective PCM driver circuit for the pump control output.
  • 4
    Corroded or backed-out connector pins at the pump or PCM.
  • 5
    Damaged wiring routed too close to exhaust or moving components.
  • 6
    Failed pump relay supplying unswitched power to the control line.

Symptoms drivers notice

MIL (Check Engine light) illuminated.
EVAP system monitor does not complete (not ready for inspection).
No noticeable driveability concerns in most cases.
Possible fuel vapor odor if a real EVAP leak is also present but undetected.

How to diagnose P2409

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool and record all stored and pending DTCs before clearing anything.
  2. 2
    Inspect the leak detection pump wiring harness and connector for chafing, corrosion, or shorts to voltage.
  3. 3
    Measure voltage on the pump control circuit with the pump commanded off; voltage should be near zero.
  4. 4
    Check for proper ground reference at the pump connector.
  5. 5
    Test the pump solenoid resistance against manufacturer specification; replace the pump if out of range.
  6. 6
    If wiring and pump check out, inspect the PCM connector for corrosion and test the driver output before suspecting PCM failure.

Vehicles where we've handled P2409

Platforms in our catalogue with confirmed P2409 coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

Can I drive with P2409 set?

The vehicle is generally driveable, but the EVAP monitor will not complete and an underlying leak may go undetected, so repair should not be delayed.

Will P2409 cause a failed emissions test?

Yes, an incomplete EVAP readiness monitor will cause a failure in most inspection programs even if no other fault is present.

Is the leak detection pump the same as the EVAP canister purge valve?

No. The leak detection pump is a separate component dedicated to pressurizing or drawing a vacuum on the EVAP system for leak testing; the purge valve controls vapor flow to the intake.

Can a low battery voltage cause P2409?

A severely discharged battery can cause erratic circuit readings, but P2409 specifically points to a high-circuit condition; low battery is an unlikely sole cause.

Disabling P2409 in software

RaceTune can permanently disable P2409 — 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 P2409 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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