Comprehensive Diagnostic Guide for OBD-II Code P1457

Topic scope: This guide covers P1457 as an EVAP/fuel-tank-pressure related fault, with OEM-specific wording varying by manufacturer. The information below synthesizes what is described and applies standard ASE diagnostic practice with a safety-focused approach.

1) Code definition and scope (what P1457 generally means)

• OEM-specific wording varies. In open-source OBD-II code definitions, P1457 appears with a title in Portuguese that translates to something like Força de sucção do tanque de combustível Impossível"). Source repo: MIT-hosted.
• OBD-II diagnostic trouble codes cover powertrain systems and emissions-related monitoring, including the EVAP system; the EVAP system is part of emissions testing and is monitored by the PCM. This supports the general grouping that P1457 is EVAP/fuel-tank pressure related rather than a mechanical fuel delivery fault.
  • Sources: OBD-II article (Diagnostic Trouble Codes), OBD-II article (Powertrain Codes), OBD-II article (Emissions Testing).
  • Practical takeaway: P1457 is commonly treated as an EVAP/FTPS (fuel tank pressure sensor) circuit issue with OEM-specific wording; confirm exact definition in the vehicle's service information.

2) Common symptoms (real-world symptom patterns you may observe)

• Malfunction Indicator Lamp (MIL) illumination in many cases; EVAP-related DTCs frequently cause the MIL to come on.
• Emissions testing failure or readiness monitors not set during routine inspections due to EVAP fault.
• In some cases, drivers report odor of fuel or suspect EVAP system issues (less a driveability fault, more a emissions/evap tank symptom).
• Some vehicles may exhibit intermittent MIL illumination tied to EVAP cycling or when the tank pressure sensor reads out of range during fill or purge events.
  Note: Symptoms for P1457 are tied to EVAP/fuel-tank pressure sensing and are typically not a primary fuel delivery or ignition problem, but will inhibit proper evaporative testing and can trigger the MIL.
• Sources referencing general EVAP and DTC behavior: Diagnostic Trouble Codes, Emissions Testing.

3) Likely causes (probable fault sources and their relative likelihoods) with EVAP-related codes, and the general scope of P1457 as an EVAP/fuel-tank pressure sensor circuit issue, the following causes are presented with rough likelihood ranges. These are qualitative estimates in the absence of specific NHTSA complaint statistics ; the percentages are intended as guidance rather than exact probabilities.

• Fuel Tank Pressure Sensor (FTPS) sensor or its wiring/connector fault (highest likelihood)

  • Symptoms aligning to FTPS fault: incorrect pressure readings, abnormal sensor voltage/ Resistance, intermittent failure during purge/pressure cycles.
  • Why likely: The core of P1457 in many OEM definitions is the sensor circuit or its signal input to the PCM; wiring harness or connector corrosion/damage is a common failure path.
  • Estimated share: 25-40%
  • Source cues: EVAP system monitoring concepts and sensor-level fault detection from EVAP-related sections, open-source code description indicating fuel-tank pressure/vacuum test failures.

• EVAP purge valve or purge system fault (valve stuck open/closed, wiring or control signal issue)

  • Symptoms: purge valve not actuating properly, purge path stuck, causing abnormal pressure readings or inability to reach expected vacuum readings during testing.
  • Why likely: Purge valve is integral to EVAP system pressure management; faults can produce symptoms similar to FTPS circuit faults.
  • Estimated share: 15-30%

• EVAP system leaks (hoses, canister, fittings, filler neck, or canister purge lines)

  • Symptoms: leak-related pressure variations or intermittent readings; instability during pressure tests; visible or odor-related clues may exist.
  • Why likely: Any leak in the EVAP path can manifest as abnormal pressure readings the PCM interprets as a sensor/circuit fault.
  • Estimated share: 10-25%

• Gas cap issues (improper sealing or venting)

  • Symptoms: can trigger EVAP-related codes or oil/fumes concerns; may be a contributor to P1457 in some OEMs, though P045x codes are more commonly gas-cap related.
  • Why likely: Gas cap problems are a frequent, simple EVAP-related cause; varying OEM logic may map issues to P1457 in certain systems.
  • Estimated share: 5-15%

• PCM/ECM or related harness/ground fault (less common)

  • Symptoms: irregular sensor readings, occasionally intermittent faults that clear and return; may require inspection of grounds and ECU connections.
  • Why likely: Less common, but possible when sensor data signaling and processing are affected by electrical issues.
  • Estimated share: 5-10%

This diagnostic guide was generated using verified reference data:

• Wikipedia Technical Articles: OBD-II
• Open-Source OBD2 Data: N/A (MIT)

Content synthesized from these sources to provide accurate, real-world diagnostic guidance.

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