P0456 on Jeep
Evaporative Emission Control System Leak Detected (Very Small Leak)
P0456 on Jeep vehicles indicates evaporative emission control system leak detected (very small leak). Au7o has documented this code across 2 Jeep models — most commonly on Grand Cherokee, Wrangler. This emissions code means the evaporative emission (EVAP) control system has detected a very small leak — even tinier than the one flagged by P0442, roughly equivalent to a 0.020-inch hole. The EVAP system traps fuel vapors from the tank and prevents them from escaping into the atmosphere, and the computer tests for leaks by sealing the system and watching for pressure or vacuum loss. Because the leak is so small, the cause is often subtle, but a loose or worn gas cap is still the most common and easiest to check. It generally indicates a minor seal, hose, or valve leak somewhere in the fuel vapor system. Typical repair costs on Jeep range from $25 to $450, depending on the specific model and root cause.
Common Causes of P0456
- •Loose, worn, or faulty gas cap or cap seal
- •Cracked or loose EVAP hose or line
- •Leaking vent valve or purge valve not sealing
- •Damaged O-ring or seal at the fuel filler neck
- •Small crack or leak in the charcoal canister
- •Leaking fuel tank or sending unit gasket
- •Loose or corroded EVAP component connection
P0456 on Jeep by Model
Jeep Grand Cherokee(1 issue)
- 2015 P0455/P0456 From a Split Purge Hose - TSB 25-002-15 Rev. A2015
FCA TSB 25-002-15 Rev. A covers a narrow population of 2015 WK Grand Cherokee vehicles built on or after November 16, 2014 and on or before January 17, 2015. On a covered vehicle with P0455 and/or P0456, a split evaporative-emissions purge-valve hose can prevent the system from sealing. The bulletin specifies 68189075AE for the 3.6L ERB engine and 68189065AD for the 5.7L EZH engine. It does not support the old card's blanket 2005-2021 claim that these codes are an ESIM failure.
Jeep Wrangler(1 issue)
- EVAP Leak Detection Pump / ESIM Module Failure Triggers P0455, P0456 & P0457 (Often Misdiagnosed as Gas Cap)2007-2018
The JK-generation Jeep Wrangler uses Chrysler's Natural Vacuum Leak Detection (NVLD) approach for its evaporative emissions (EVAP) system, implemented through a leak detection device commonly called the ESIM (Evaporative System Integrity Module) or leak detection pump (LDP). Rather than an active vacuum pump, this module monitors natural temperature-induced pressure/vacuum changes in the fuel/EVAP system to confirm the system is sealed. The ESIM is a known, high-frequency failure point: its internal diaphragm/seal hardens or cracks (or the housing cracks), causing the ECM to falsely detect an EVAP leak even when the system is actually sealed. The result is a check-engine light and one of several EVAP leak codes. Because the very first thing the code points the owner toward is the fuel cap, this failure is routinely misdiagnosed: owners (and shops) replace the gas cap one or more times, the light returns, and the actual culprit is the cheap ESIM/leak-detection module bolted to the charcoal canister. The module is a small white rectangular unit that twists/mounts onto the EVAP charcoal canister, located beneath the vehicle near the fuel tank / just ahead of the rear axle (driver side on most JKs). It is non-safety, non-drivability affecting, but it will cause a persistent CEL and an emissions/smog-test failure. This affects the 3.8L V6 (2007-2011) and 3.6L Pentastar (2012-2018) JK Wranglers, including 2-door and Unlimited 4-door.
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View P0456 across all makes →Frequently Asked Questions
What does P0456 mean on Jeep?▼
P0456 stands for "Evaporative Emission Control System Leak Detected (Very Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a very small leak — even tinier than the one flagged by P0442, roughly equivalent to a 0.020-inch hole. The EVAP system traps fuel vapors from the tank and prevents them from escaping into the atmosphere, and the computer tests for leaks by sealing the system and watching for pressure or vacuum loss. Because the leak is so small, the cause is often subtle, but a loose or worn gas cap is still the most common and easiest to check. It generally indicates a minor seal, hose, or valve leak somewhere in the fuel vapor system. On Jeep specifically, this code is documented across 2 models.
What causes P0456 on Jeep vehicles?▼
Common causes on Jeep: Loose, worn, or faulty gas cap or cap seal, Cracked or loose EVAP hose or line, Leaking vent valve or purge valve not sealing, Damaged O-ring or seal at the fuel filler neck, Small crack or leak in the charcoal canister. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0456 on a Jeep?▼
Repair costs on Jeep range from $25 to $450, depending on the specific model and root cause.
Which Jeep models have P0456 documented?▼
Au7o has documented P0456 on 2 Jeep models: Grand Cherokee, Wrangler.