enbgde
P1456 Manufacturer-specific Basic entry

Evap Emission Control Sys Vent Control Valve Circuit

Updated 2026-10-02 · Manufacturer-specific powertrain

Severity
Low
Typical repair cost
60 – 500 EUR
System
Powertrain

This is a manufacturer-specific code. Its exact meaning can differ between makes; the definition below follows the most common usage.

What it means

P1456 is defined as "Evap Emission Control Sys Vent Control Valve Circuit". the engine control module stores it when the monitored condition for this component or system is outside the limits programmed by the manufacturer.

This entry is compiled automatically from the standard definition and typical diagnostic practice for this type of fault. A detailed, reviewed article is in preparation.

Advertisement728 × 90

Symptoms

  • Check engine light on
  • Rough or unstable idle
  • Hesitation or poor acceleration
  • Increased fuel consumption
  • Possible limp mode with reduced power

Common causes

  1. Evap Emission Control Sys Vent Control Valve Circuit worn, contaminated or out of calibration
  2. Mechanical problem in the system the sensor measures
  3. Air, vacuum or exhaust leak influencing the reading
  4. Wrong or low-quality replacement part
  5. Wiring resistance causing a small voltage offset

How to diagnose

  1. Compare the live Evap Emission Control Sys Vent Control Valve Circuit reading with a known-good value or a second sensor at idle and at 2500 rpm
  2. Check for air, vacuum or exhaust leaks that could skew the reading
  3. Inspect the component for contamination and clean it if the design allows
  4. Verify the part number is correct for the engine
  5. Replace the Evap Emission Control Sys Vent Control Valve Circuit if the reading remains out of specification

Frequently asked questions

Can I keep driving with P1456?

Yes. The fault does not affect safety or driveability, but it will keep the warning light on and may fail an inspection.

Will clearing P1456 fix it?

No. Clearing only erases the stored code; it returns as soon as the monitor runs again unless the cause is repaired.

Related codes

P1454P1455P1457

Nearby codes in this group