P2412

Fuel Cap Sensor/Switch Circuit Low

P2412 is a generic OBD-II powertrain diagnostic trouble code: Fuel Cap Sensor/Switch 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
P2412
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2412 means

P2412 is the low-circuit counterpart to P2408 for the fuel cap presence sensor or switch. The PCM logs this code when the sensor or switch signal voltage falls below its calibrated lower threshold, suggesting an open circuit, short to ground, or failed sensor that cannot maintain the expected signal level.

In EVAP systems that use a cap-installed confirmation input, a missing or consistently low signal may cause the PCM to interpret the fuel cap as absent, which can interfere with the EVAP large-leak test. The sensor is typically a simple switch or voltage divider located in the filler neck area and is vulnerable to moisture ingress and mechanical damage.

Circuit diagnosis should begin at the sensor connector: verify reference voltage is present and the ground path is intact, then measure the signal voltage. A reading near zero with the cap installed points to either a short to ground in the signal wire or a failed sensor. Correct the circuit fault before condemning the PCM.

Common causes

Most-frequently reported root causes when P2412 is logged.

  • 1
    Short to ground in the fuel cap sensor signal wire.
  • 2
    Open reference voltage circuit preventing the sensor from producing a signal.
  • 3
    Failed fuel cap sensor with a shorted or open internal element.
  • 4
    Corroded connector causing high resistance in the supply or signal line.
  • 5
    Broken wire in the harness between the sensor and PCM.
  • 6
    Moisture ingress into the sensor housing degrading the internal switch.
  • 7
    PCM input circuit fault reading the signal as low when it should be within range.

Symptoms drivers notice

MIL illuminated with P2412 stored.
EVAP monitors may report incomplete or set companion EVAP codes.
No drivability impact in most cases.
Possible interference with other EVAP diagnostic routines requiring cap-installed confirmation.

How to diagnose P2412

A typical diagnostic flow when this code is present.

  1. 1
    Read all stored DTCs and note any companion EVAP codes.
  2. 2
    Inspect the fuel cap sensor connector and wiring harness for moisture, corrosion, or damage.
  3. 3
    Measure the reference supply voltage at the sensor connector; it should match the specified level.
  4. 4
    Measure the ground circuit resistance; it should be near zero ohms.
  5. 5
    Measure the signal voltage with key on and cap installed; compare to specification.
  6. 6
    Trace the signal wire from connector to PCM for shorts to ground or open circuits.
  7. 7
    After repair, clear codes and confirm the EVAP monitor completes successfully.

Vehicles where we've handled P2412

Platforms in our catalogue with confirmed P2412 coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

Does P2412 mean my fuel cap is missing?

No. P2412 is a circuit-low fault in the sensor that detects cap presence. The fuel cap may be correctly installed but the sensor circuit is not producing the expected signal.

Can water cause P2412?

Yes. The filler neck area is exposed to the elements, and moisture in the sensor connector can cause a short to ground that produces a low-circuit reading.

How is P2412 different from a fuel cap EVAP leak code?

EVAP leak codes are set by pressure or flow testing. P2412 is purely an electrical circuit fault in the cap sensor circuit, unrelated to EVAP pressure results.

Can I drive with P2412?

The vehicle should be drivable, but the MIL will remain on and EVAP readiness may not complete, affecting emissions testing.

Disabling P2412 in software

RaceTune can permanently disable P2412 — 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 P2412 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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