No recalls found in NHTSA database
No NHTSA complaints found for Honda CR-V 2017-2023 with code P0456. This guide uses general automotive knowledge for the P0456 diagnosis on these vehicles and notes data limitations where applicable.
CODE MEANING AND SEVERITY
- What P0456 means: Evaporative Emission Control System Small Leak detected. The engine control module (ECM/PCM) detected a leak in the EVAP system that is too small for the system’s standard leak test to pass.
- Severity and impact:
- Not typically a safety issue or immediate drivability problem.
- Commonly causes a service engine soon / check engine light (MIL) and possible emissions test failure.
- Fuel economy impact is usually minor unless the underlying leak causes additional venting losses.
- In many cases, the fix is simple (e.g., gas cap) but could require more extensive EVAP system service if the leak is real and persistent.
COMMON CAUSES ON HONDA CR-V
- Gas cap issues:
- Loose, cracked, or damaged gas cap seal; fuel cap not torqued properly after refueling.
- Worn gasket or missing cap.
- EVAP hoses and fittings:
- Leaking or cracked hoses between the fuel fill neck, charcoal canister, and purge valve.
- Disconnected or pinched hoses due to road debris or improper service.
- EVAP purge valve/solenoid:
- Purge valve stuck open or closed, or electrical fault causing improper operation.
- Wiring/connectors degraded.
- Charcoal canister (evaporative canister) issues:
- Cracked or saturated canister due to prolonged exposure to fuel vapors.
- Canister saturation or damage increasing system leakage.
- Filler neck and lines:
- Cracked filler neck, damaged O-ring, or seal around the filler area.
- EVAP sensors and seals:
- Pressure sensor or leak detection pump (if equipped) failures or dirt/contamination on sensor.
- Secondary causes (less common but possible):
- Exhaust or intake vacuum leaks that affect EVAP monitor readings.
- ECM/PCM software not calibrating properly (rare; usually resolved with updates if applicable).
SYMPTOMS
- Check Engine Light / MIL illuminated (P0456 stored and/or pending).
- Gas cap warning light or fuel smell complaints (in some cases, a weak fuel vapor odor may be noticed).
- No obvious loss of engine power or drivability issues; MPG impact is usually small unless the leak is persistent.
- Infrequent drive-cycle rechecks: some vehicles may not trigger repeat cycles if the leak is intermittent or small.
- In some cases, the vehicle will pass a visual inspection but fail an evaporative emissions test due to a small leak.
DIAGNOSTIC STEPS
A thorough, logical approach improves the odds of locating a tiny EVAP leak. Use a scan tool capable of EVAP diagnostics and, if available, a smoke machine.
Step 1: Confirm and document
- Retrieve DTCs with a reliable OBD-II scanner; note any related codes (P0440–P0446, P0455). Record freeze-frame data and fuel-fill history if available.
- Clear codes and drive a short trip; see if P0456 reappears and after how many drive cycles.
Step 2: Inspect the gas cap system
- Check the gas cap for wear, cracks, or a loose fit. Replace with a genuine or OE-quality cap if in doubt.
- After replacing, reset the ECM/drive cycle and recheck. A cap issue is a common cause for P0456.
Step 3: Visual inspection of EVAP plumbing
- Inspect visible EVAP hoses from the filler neck to the canister and purge valve for cracks, splits, kinks, or disconnections.
- Look for signs of rubbing or contact with sharp edges that could cause wear over time.
- Inspect the charcoal canister for cracks or damage (look for fuel smells or damp spots around the canister area).
Step 4: Inspect purge valve and related hardware
- Test purge valve operation with a scanner to see if it is energizing/de-energizing as commanded.
- Check electrical connectors and wiring for corrosion or looseness.
- If accessible, perform a controlled resistance/continuity check per service data.
Step 5: System pressure/leak testing
- If a smoke machine is available, perform an EVAP smoke test to locate small leaks. Seal the system and introduce smoke; watch for smoke escaping at any joints, hoses, or canister cracks.
- If a smoke machine isn’t available, a supervised soapy-water leak test can help: with the system pressurized (engine off, ignition on if your tool allows), apply soapy water to suspected areas and look for bubbling.
- For some CR-Vs, a hand-held EVAP pressure tester can pressurize the system slightly and reveal leak points; follow tool instructions and vehicle specs.
Step 6: Component-by-component elimination
- If no leak is found visually, test the purge valve operation and the vent valve (if equipped) separately.
- Consider replacing the purge valve if it shows improper operation (even if there’s no apparent leak).
- If the leak persists and the system is pressurized without obvious leaks, a damaged canister or hidden hoses may be the culprit. Replacement of the canister or sections of EVAP tubing may be required.
Step 7: After repairs
- Clear the codes and perform multiple drive cycles to ensure the EVAP monitor completes without re-tripping.
- Monitor for any subsequent P0456 reoccurrence. If it returns, re-evaluate the canister, hoses, and purge/vent valves with more advanced diagnostics.
RELATED CODES
- P0440 Evaporative Emission Control System Malfunction
- P0441 Evaporative Emission Control System Incorrect Purge Flow
- P0442 Evaporative Emission Control System, Small Leak Detected
- P0443 Evaporative Emission Control System Malfunction (Note: model/ year dependent)
- P0444 Evaporative Emission Control System Purge Flow
- P0455 EVAP System Large Leak Detected
- P0457 Evaporative Emission Control System Small Leak Detected (often at a different threshold)
Note: P0456 is the listed small leak code; multiple EVAP codes are related and can appear if the system is at fault beyond just a tiny leak.
REPAIR OPTIONS AND COSTS (2025 PRICES)
Prices shown are approximate ranges for parts and labor in 2025 and vary by region, shop, and vehicle condition. They are intended as a guide only.
Gas cap replacement
- Parts: $12–$40
- Labor: $15–$40
- Total: $27–$80
- Notes: Most affordable fix. If the cap is the root cause, this resolves P0456 quickly.
EVAP hose(s) and clamps repair
- Parts: $5–$60
- Labor: $40–$120
- Total: $45–$180
- Notes: Common when hoses crack or become loose. Easy DIY when accessible.
Purge valve (solenoid) replacement
- Parts: $60–$180
- Labor: $80–$180
- Total: $140–$360
- Notes: A frequent source of EVAP issues; replace with OEM/quality part.
Canister (charcoal canister) repair or replacement
- Parts: $150–$450
- Labor: $200–$400
- Total: $350–$850
- Notes: More involved; may be required if the canister is cracked or saturated.
EVAP system test/diagnostic service (smoke test or pressure test)
- Parts: N/A (test equipment rental or use)
- Labor: $100–$250
- Total: $100–$250
- Notes: Many shops charge for the diagnostic process; a smoke test is highly effective for locating tiny leaks.
Miscellaneous hardware (hoses, valves, sensors)
- Parts: $5–$150
- Labor: $40–$140
- Total: $45–$290
- Notes: Depending on what’s found, multiple small parts may need replacement.
Total repair cost range (typical scenarios)
- Cap or small hose fix: $30–$200
- Purge valve or single-hose fix: $140–$450
- Canister-related fix: $350–$900
- Full EVAP system diagnostic with smoke test: $100–$300 (plus any parts)
DIY VS PROFESSIONAL
DIY-friendly options:
- Check and replace gas cap if damaged or not sealing properly.
- Tighten or replace visually damaged EVAP hoses with basic hand tools; fix loose clamps.
- Inspect accessible hoses and fittings for obvious signs of wear or cracks.
- If you have the right tools (hand-held EVAP pressure tester or smoke machine) and experience, you can perform leak testing and some hose/valve resealing.
When to call a professional:
- The gas cap is not the problem, and there are no obvious hose leaks.
- You do not have access to a smoke machine or EVAP pressure tester.
- The leak is intermittent, internal, or located in hard-to-reach areas (near the canister, underbody lines, or behind the rear wheel well).
- You suspect a faulty purge valve, vent valve, or damaged charcoal canister.
- Repeated drive cycles do not clear the code after fixes.
- Emissions compliance or warranty concerns require accurate verification.
Tips if you DIY:
- After any EVAP repair, drive the vehicle normally for several miles and then do a longer drive to allow the EVAP monitor to run its checks.
- Disconnecting the battery to clear codes may reset some learning; recheck after a few cycles.
- Ensure replacement parts are compatible with the 2017–2023 CR-V (Honda OEM or equivalent quality).
PREVENTION
- Use good fuel and avoid consistently filling to the very brim; this reduces vapor pressure stress on the EVAP system.
- Always ensure the gas cap is properly tightened after fueling.
- Inspect the EVAP system during routine maintenance, especially if you notice a fuel odor or after recent service near the fuel system.
- Address cracked or brittle hoses early; replacement before leaks worsen saves money and time.
- If you operate in harsh climates or expose the vehicle to road debris, inspect the EVAP lines more frequently for cracks or abrasion.
- When replacing EVAP components, prefer OEM or high-quality equivalents and ensure proper torque on clamps and fittings to prevent leaks.
Data limitations
- The provided data indicates no recalls or owner complaints for this exact vehicle/issue combination in the NHTSA database. No recalls found in NHTSA database. The guide uses general EVAP knowledge and typical CR-V EVAP behavior to outline diagnosis and repair approaches. Actual conditions, regional regulations, and dealer/service policy can vary. If you have warranty coverage, verify with the dealer for any applicable service bulletins or updates not captured in this data excerpt.
If you’d like, tell me your CR-V’s mileage, whether the MIL is steady or flashing, whether you notice any fuel odor, and if you’ve recently refueled or replaced any EVAP-related parts. I can tailor the diagnostic plan and cost estimates more precisely to your situation.