P0456 on 2012-2019 Dodge Journey: Causes and Fixes for Small EVAP Leaks

What's Unique About the 2012-2019 Dodge JOURNEY

On the Dodge Journey and other Chrysler/Dodge vehicles of this era, the EVAP system uses an Evaporative System Integrity Monitor (ESIM) switch, which is a common failure point that can trigger a P0456 code. This component can get stuck or fail electronically, falsely reporting a leak. Additionally, several Technical Service Bulletins (TSBs) indicate that this code can sometimes be triggered by a software glitch in the Powertrain Control Module (PCM), which can be resolved with an update from a dealership instead of replacing parts.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light is on
• Gas cap warning light may appear on the dashboard.
• A faint smell of gasoline, particularly after refueling or while the vehicle is parked.
• A whooshing sound from the fuel tank area when opening the gas cap if the system is not venting properly.

Most Likely Causes

1. Loose or Faulty Gas Cap 🔴 High Probability The gas cap seal is a rubber component that degrades over time from exposure to fuel vapors and weather, typically between 50,000 and 100,000 miles, causing it to lose its sealing ability. Many owners in forums report that only an OEM Mopar cap will solve the problem, as some aftermarket caps do not seal correctly.
   How to confirm: Inspect the gas cap for cracks or damage to the rubber O-ring. Ensure it is tightened until it clicks at least once. A visual inspection of the fuel filler neck for rust or debris is also recommended, as a clean sealing surface is critical.
   Typical fix: Replace the gas cap. It is highly recommended to use an OEM Mopar gas cap (Part # 52124512AA, which may be superseded by 52030433AB) to ensure a proper seal.
   Est. part cost: $15-$40
2. Faulty EVAP Purge Valve/Solenoid 🟡 Medium Probability
   How to confirm: The purge valve is located in the engine bay, typically near the back corner. 🎬 Watch: How to identify a failed purge valve solenoid. It is normally closed. You can remove it and try to blow through it; if air passes, it is stuck open and needs replacement. A handheld vacuum pump can also be used to see if it holds a vacuum.
   Typical fix: Replace the purge valve. This is a relatively simple repair involving disconnecting two hoses and an electrical connector. The Mopar part number is often 04891731AC.
   Est. part cost: $25-$70
3. Faulty EVAP System Integrity Monitor (ESIM) Switch 🟡 Medium Probability This component, also called a leak detection pump, is a known high-failure item on many Dodge/Chrysler products including the Journey and its platform mates like the Grand Caravan. It can get stuck internally or fail electronically, falsely reporting a leak even when none exists.
   How to confirm: The ESIM is located on the charcoal canister under the vehicle, near the spare tire. Diagnosis often involves ruling out other causes first or performing a smoke test. Due to its high failure rate, it is often replaced when a new gas cap and purge valve do not resolve the code.
   Typical fix: Replace the ESIM switch. This involves lowering the spare tire for access, disconnecting a hose and electrical connector, and twisting the switch counter-clockwise 🎬 See this walkthrough for diagnosing and replacing the ESIM. to remove it from the canister.
   Est. part cost: $30-$70
4. Cracked or Disconnected EVAP Hoses ⚪ Low Probability
   How to confirm: Visually inspect all accessible EVAP hoses in the engine bay and under the vehicle between the engine and the fuel tank for cracks, brittleness, or loose connections. A smoke test is the most effective way to find a hard-to-see leak.
   Typical fix: Replace the cracked section of hose or the entire hose assembly. Small rubber connectors can often be replaced with a generic piece of vacuum hose of the correct diameter.
   Est. part cost: $10-$50
5. Powertrain Control Module (PCM) Software Update Needed ⚪ Low Probability
   How to confirm: This can only be confirmed by a Dodge dealership or a qualified shop with access to OEM service information. They can check if your vehicle's VIN has any pending software updates related to the EVAP system by referencing TSBs like #18-081-17, #18-086-16, or #18-080-17.
   Typical fix: A technician flashes the PCM with the latest software version using a wiTECH scan tool. This is not a parts replacement and typically takes less than an hour.
   Est. part cost: $0 (if under warranty) - $200

Rare But Worth Checking

• Cracked EVAP Charcoal Canister: The canister body itself can develop a hairline crack, creating a small leak. This is usually found with a smoke test after all other components have been checked.
• Leaking Fuel Filler Neck: Rust or corrosion on the metal tube where the gas cap seals can prevent a proper seal, even with a new gas cap. The surface must be clean and smooth.
• Leaking Fuel Tank Sending Unit Gasket: A user on a Dodge Journey forum mentioned that it is possible for the gasket that attaches the fuel-sending unit to the gas tank to deteriorate, reducing tank pressure and triggering the code.

Diagnosis Steps

1. Check the Gas Cap: Remove, inspect the seal for damage, and reinstall it, ensuring it clicks several times. Clear the code. If the light returns, replace the cap with an OEM Mopar part (e.g., 52124512AA).
2. Visual Inspection: Check the EVAP purge valve and its hoses in the engine bay for any obvious cracks or loose connections. The valve is typically in the rear corner of the engine compartment.
3. Inspect Under the Vehicle: Visually inspect the EVAP hoses running to the charcoal canister and the ESIM switch for any visible damage. The canister and ESIM are located under the vehicle, usually accessible by lowering the spare tire.
4. Test/Replace Purge Valve: If the gas cap is not the issue, the purge valve is the next most accessible part. Remove it and test if it's stuck open by blowing through it. If air passes, replace it (Mopar P/N 04891731AC).
5. Test/Replace ESIM Switch: If the code persists, the ESIM switch on the charcoal canister is the next logical part to replace, given its high failure rate.
6. Check for TSBs: Contact a dealer with your VIN to see if any software updates, like those mentioned in TSBs #18-081-17, #18-086-16, or #18-080-17, apply to your vehicle.
7. Smoke Test: If the leak is still not found, a smoke test is the definitive way to find the source. This involves injecting pressurized smoke into the EVAP system (often through the purge valve line) 🎬 Watch: A professional smoke test and diagnosis for P0456. and looking for where it escapes.

Parts You'll Likely Need

• Gas Cap (OEM #52124512AA (superseded by 52030433AB)) — This is the most frequent cause of a P0456 code due to the natural wear of the rubber seal. Using an OEM cap is strongly recommended.
  Trusted brands: Mopar
  OEM price range: $25-$40
  Aftermarket price range: $15-$25
• EVAP Purge Valve / Solenoid (OEM #04891731AC) — This valve can get stuck open, creating a constant small leak. It's a common failure point in the EVAP system.
  Trusted brands: Mopar, Standard Motor Products (SMP), Bosch
  OEM price range: $40-$70
  Aftermarket price range: $25-$50
• Evaporative System Integrity Monitor (ESIM) Switch (OEM #4861962AD) — This switch is a very common failure point on Dodge/Chrysler vehicles. It can fail electronically and falsely report a leak, even when a smoke test shows no leaks.
  Trusted brands: Mopar
  OEM price range: $50-$75
  Aftermarket price range: $30-$50

Related Codes That Often Appear With This One

• P0441 — P0441 (EVAP Purge System Performance) often appears with P0456, as both can be caused by a faulty purge valve or a PCM software issue. TSB #18-081-17 lists both codes as being resolved by a PCM update for the 2015 model year.
• P0455 — This code indicates a large EVAP leak. Sometimes a component failure can initially present as a small leak (P0456) and worsen into a large leak (P0455). A YouTube video shows a 2011 Journey with both codes, which was fixed by replacing the ESIM.
• P0457 — This code indicates a leak detected due to a loose fuel cap. It is very similar to P0456 and points directly to the gas cap as the primary suspect. A video guide for a 2009 Journey shows an ESIM replacement fixing both P0456 and P0457.

Technical Service Bulletins (TSBs) & Recalls

• 18-081-17: For 2015 models with 2.4L or 3.6L engines, this TSB involves a PCM software update to address several codes, including P0456, P0441, and P0443.
• 18-086-16: For 2014 models, this TSB reprograms the PCM to fix multiple issues, including P0456.
• 18-080-17: For 2016 models, this TSB updates PCM software to correct several potential DTCs, including P0456.
• 18-050-16 REV. A: For 2012 models, this TSB provides a PCM software update that addresses P0456 among other codes.
• 9003801: A 2017 communication advises technicians to contact a specific engineer before repairing a P0456, suggesting an ongoing investigation or specific diagnostic need at the time.
• 1804823: A 2023 TSB that provides updated procedures for using the dealer scan tool (wiTECH) to perform the small leak verification test, which is used to confirm a P0456 leak.

Platform-Specific Known Issues

• An owner of a 2017 Journey reported the "GAS CAP LIGHT" coming on, followed by the Check Engine Light with code P0456, but noted the vehicle remained drivable. [ODI #11065743]
• Multiple Technical Service Bulletins (#18-081-17, #18-086-16, #18-080-17) exist for this year range, indicating that a P0456 code can be caused by a software issue in the Powertrain Control Module (PCM) and may be fixed with a software update rather than parts replacement.
• A detailed repair story on DodgeForum.com for a 2014 Journey with P0456 involved first checking the gas cap (no help), then testing the purge valve (was OK), and finally replacing the ESIM switch (which was stuck open), which solved the problem.
• A user on the Dodge Journey Forum with a 2017 model reported that after replacing the gas cap, purge valve, and leak detection pump, the code persisted, highlighting that diagnosis can sometimes be complex.

Mechanic-Grade Diagnostic Values

• EVAP Purge Valve Solenoid Resistance — expected: 14-30 Ohms. Failure: A reading significantly outside of this range indicates a faulty internal coil.

Scan Tool Commands That Help

• wiTECH: Small Leak Verification Test (SLVT) — According to TSB #1804823, this test is mandatory when diagnosing P0456. It must be run before repairs to verify a leak is present and after repairs to confirm the fix, as a road test will not immediately confirm the repair.

Wiring & Ground Locations

• G904 — Right rear of the engine compartment.. This is a primary engine-area ground. A poor connection here could potentially affect the operation of nearby components like the EVAP purge solenoid.
• G304 — Under the driver's seat.. This is a major chassis ground point. While not directly tied to the EVAP system, poor grounds can cause unpredictable electrical issues throughout the vehicle.
• EVAP Purge Solenoid Location — Left rear corner of the engine compartment.. This is the physical location for visual inspection and testing of the purge solenoid.
• ESIM Switch Location — On the charcoal canister, located under the vehicle near the spare tire. Requires dropping the spare tire for access.. This is the physical location for inspection and replacement of the ESIM, a common failure point.

Real Owner Repair Stories

• DodgeForum.com user (2014 Dodge Journey) — Check engine light with P0456 and 'check gas cap' message.
  ❌ Tried (didn't work) Replaced gas cap, Removed and tested the EVAP purge valve in the engine bay (it tested OK)
  ✅ What actually fixed it The ESIM switch (also called canister purge valve or vapor leak detection pump) located on the charcoal canister under the spare tire was stuck open. Replacing the ESIM resolved the code.
• Reddit user skulnick1244 (2018 Dodge Journey GT 3.6L with 80k miles) — P0455, P0456, P0457 codes.
  ❌ Tried (didn't work) Replaced gas cap with a non-OEM part., Ordered an EVAP canister purge valve.
  ✅ What actually fixed it After replacing the non-OEM gas cap and the purge valve, and performing multiple battery disconnects and ignition cycles over two months, the codes eventually went away and did not return. This suggests one of the replaced parts was the culprit, but the system took a long time to reset and confirm the fix.

"I Checked Everything" — The Actual Cause

• In many cases with Chrysler/Dodge vehicles, a smoke test will show no leaks, yet the P0456 code persists. This is a strong indicator that the ESIM switch has failed electronically. The switch itself is not leaking, but it is incorrectly reporting a leak to the PCM. A technician demonstrated that a bad ESIM will fail a simple bench test even though it holds pressure, while a good one will correctly signal when pressure or vacuum is applied.

OEM Part Supersession History

• 4861962AA → 4861962AB, 4861962AC, 4861962AD — Standard part revisions by the manufacturer.
  Heads up: The most current part number is 4861962AD. This part is also listed as replacing 4891685AA and 4891685AB.