P0457 on Dodge: How to Diagnose & Fix
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
2 Dodge models · 2 documented issues · $25-$500 repair
P0457 on Dodge by model: symptoms, diagnosis and fix
The Dodge Challenger's evaporative emissions (EVAP) leak-detection device — the Evaporative System Integrity Module/Monitor (ESIM), the successor to Chrysler's older NVLD (Natural Vacuum Leak Detection) pump — is a very common failure point across the LX/LA platform (2008-2023). The ESIM is a mechanical, non-solenoid device (housing, two check valves/weights, a diaphragm, and a switch) bolted to the charcoal canister behind the rear passenger fender-well liner. It performs an engine-off non-intrusive test for small leaks and an engine-running test for medium/large leaks, and the PCM relies on it for ALL EVAP leak diagnostics. When the ESIM's diaphragm or switch fails, the PCM falsely concludes the sealed EVAP system is leaking and sets P0456 (small leak), P0455 (large leak), or a generic P0440, illuminating the check-engine light. Because the code description points to a leak, the part is repeatedly misdiagnosed: owners and shops replace the gas cap (sometimes multiple times), get a clean smoke test showing no actual leak, yet the code returns. Multiple forum threads document owners chasing this for months — replacing the gas cap, then the purge/canister valve — before the ESIM ("vapor leak detection pump") is finally identified as the real fault. One owner reported spending roughly $2,500 over repeated visits before the issue was resolved. In some cases the leak-detection pump was simply found unplugged behind the wheel-well liner.
Common Symptoms
- Check-engine light (MIL) on with no driveability problems
- P0456 (small EVAP leak), P0455 (large EVAP leak), or P0440 stored, sometimes intermittently together
- Code returns shortly after clearing or after replacing the gas cap
- Smoke test shows no actual leak yet the code persists
- Gas-cap / 'tighten fuel cap' warning message that won't clear
- Faint fuel-vapor smell in some cases
- May cause an emissions/inspection test failure
How to Fix
Don't just keep replacing the gas cap. First inspect/tighten the cap and, if replacing, use only an OEM Mopar cap (e.g., P/N 52030377AB) since aftermarket caps frequently re-trigger the code. Then have a smoke test performed: if the smoke test shows NO leak but P0455/P0456/P0440 persist, the ESIM (leak detection pump) itself is the cause and should be replaced. The ESIM is located on the charcoal canister behind the rear passenger-side fender-well liner. DIY replacement takes roughly 40-45 minutes: a 22mm socket to pull the rear wheel, a clip/push-pin tool plus a 10mm socket to pull the liner, then unclip and swap the module. Also confirm the ESIM electrical connector is fully seated — several owners found it unplugged. After replacement, clear the codes and complete a drive cycle so the EVAP monitor can re-run and verify the fix. The ESIM part itself is inexpensive (~$25-$90 OEM/aftermarket, e.g., APDTY 160319), making this a low-cost DIY repair; a shop diagnosis-plus-replacement typically runs $100-$500 (dealer quotes can reach ~$800).
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Mopar 4861962AD Evaporative System Integrity Module
Replace the ESIM after cap/connector inspection and a smoke test shows no external leak but the EVAP monitor still implicates the module Fitment: Live fitment lists 2008-2023 Challenger 3.5L, 3.6L, 5.7L, 6.1L, 6.2L and 6.4L; supersedes 4…
- Genuine Mopar 5278632AG fuel filler cap
Early-car cap branch when seal inspection confirms the cap itself is leaking or damaged Fitment: 2008-2010 Challenger 3.5L/5.7L/6.1L only; the solution's example 52030377AB should not be treated as the universal Challenger number $31.46 …
- Genuine Mopar 52030389AB fuel filler cap
Later cap branch only when inspection or smoke testing identifies the cap seal as the leak Fitment: 2011-2019 Challenger; supersedes 68139752AA and 52030389AA $26.62 and Add to Cart on the live OEM product page when checked
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Sources for this issue (2)
A very common and frequently misdiagnosed problem on the Dodge Charger is failure of the EVAP (evaporative emissions) leak-detection device, which causes the PCM to log P0456 (small EVAP leak), P0455 (large EVAP leak), and/or P0457 (leak detected / fuel cap loose) and illuminate the check-engine light. On 2011-and-newer Chargers the system uses an ESIM (Evaporative System Integrity Module) — a natural-vacuum-based switch (the same NVLD-style monitoring concept) mounted directly on the charcoal/EVAP canister behind the passenger-side rear wheel well. With the EVAP system sealed, the PCM watches the ESIM/NVLD switch; if the switch's internal mechanical diaphragm fails or its external O-ring seal degrades, the switch fails to close within the calibrated time and the PCM falsely reports an EVAP leak. The classic giveaway is that a smoke test shows NO actual leak yet the code keeps returning. Because the code is almost always assumed to be a loose or failed gas cap, owners (and shops) often chase the wrong part first — replacing the gas cap and purge valve before discovering the real culprit is the inexpensive ESIM module. The code is low-severity (no driveability or engine damage, only a slight fuel-economy effect) but will fail an emissions/smog test and leaves the CEL on. In a worst-case escalation, the same codes can be caused by a pinhole leak on top of the fuel tank near a fuel-pump lock ring, which requires fuel-tank replacement. On 2022+ cars, Mopar TSB 18-094-23 addresses an over-sensitive EVAP monitor that can falsely set P0455/P0456/P0440/P0441 and is corrected with a PCM software update rather than a part.
Common Symptoms
- Check-engine light (MIL) illuminated
- Stored code P0456 (small EVAP leak), P0455 (large EVAP leak), or P0457 (leak detected / fuel cap loose)
- Code returns after clearing even with a new or tight gas cap
- Smoke test shows no visible leak yet the code keeps coming back
- Occasional faint fuel odor
- Slight decrease in fuel economy
- Failed state emissions / smog test
- CEL often reappears roughly every 100 miles / per drive cycle
How to Fix
Do NOT just replace the gas cap. Start by confirming the gas cap is tight and undamaged and clearing the code; if it returns, perform a smoke test. If the smoke test shows no leak but the code persists, the failed part is almost always the ESIM (Evaporative System Integrity Module / NVLD leak-detection switch) on the charcoal canister. Replace it: OEM Mopar part number 04861962AC / 4861962AD, roughly $30-$90 for the part. It is a DIY job (about 40-45 minutes): disconnect the battery, remove the passenger-side rear wheel (22mm) and fender-well liner (10mm nut plus push-pin clips), expose the EVAP canister, unplug the ESIM connector and the fresh-air filter hose, then swap the module and reseal the O-ring. If the ESIM is good, check the EVAP purge valve/solenoid (can stick open) and inspect EVAP hoses for cracks. On 2022+ Chargers, check for Mopar TSB 18-094-23 and apply the PCM software update before replacing parts. If all of the above are ruled out and the leak is real, inspect the top of the fuel tank for a pinhole near the fuel-pump lock rings — this is rare but requires fuel-tank/O-ring replacement and can run $2,000+.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- AutoLine Pro HyperSmoke standard kit with gas-cap and cone adapters
Perform the named low-pressure smoke-test step before replacing the ESIM or other EVAP components Fitment: Universal diagnostic tool; use only its 0-1 PSI EVAP mode and follow safe vapor-system procedures $69.99, in stock and Add to Cart…
- Dorman 310-215 Evaporative System Integrity Module
Aftermarket ESIM alternative for the compatible later application after exact fitment confirmation Fitment: Direct product, but buyer must select the exact Charger year/engine before purchase; not presented for every 2006-2023 car Live U…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (2)
P0457 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0457 mean on a Dodge?
P0457 stands for "Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)." This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. On Dodge it is documented across 2 models: Challenger, Charger.
What are the most common causes of P0457?
The most common causes of P0457 are: Loose, missing, or improperly tightened fuel cap, Worn or cracked fuel cap seal/gasket, Damaged fuel filler neck or sealing surface, Cracked or disconnected EVAP hose, Stuck-open purge or vent valve, Faulty fuel cap that won't hold pressure, Leaking charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0457 on a Dodge?
Published repair estimates on Dodge range from $25 to $500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0457 on a different make?
View P0457 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.