Jeep code
P0456: on a Jeep
How much to fix P0456 on a Jeep? Typically $5 to $95 for gas cap replacement, the most common fix. This is an estimate, not a quote.
P0456 is a very small leak in the fuel vapor system, roughly a pinhole. Jeeps set it often because the vapor lines run near the frame, close to rocks, salt and mud.
General meaning of P0456: After the car is shut off, the computer seals the fuel-vapor system and checks whether pressure holds. This code means it leaks down very slowly, about as much as a hole the size of a pin. Because the leak is tiny, it is the slowest of the vapor codes to track down. See the full P0456 page.
Models to know about
| Model | Years | What to know |
|---|---|---|
| Wrangler | 2007 to 2018 | Open-air design and many owner mods mean more places for a vapor leak. |
| Grand Cherokee | 2005 to 2019 | Fuel filler neck seals and the leak detection parts. |
| Cherokee | 2014 to 2019 | Plastic vapor lines. |
| Compass | 2007 to 2017 | Smaller tank with fewer parts. |
Common causes on a Jeep
- Gas cap with a worn seal or a missing tether.
- Cracked or rusted vapor line near the frame rail.
- Leak detection pump or its filter, on older Jeeps that use that design.
- Fuel filler neck seal that dried out.
NHTSA's public complaint file shows how owners describe this kind of trouble: the 2012 Jeep Wrangler has 835 complaints on file, and 45 of them use wording like EVAP, evaporative, fuel vapor, P0456; the 2012 Jeep Grand Cherokee has 1,644 complaints on file, and 77 of them use wording like EVAP, evaporative, fuel vapor, P0456. Complaints are owner reports, not proof of a cause.
Check this first
- Replace the gas cap first with a good OEM one and drive three to five days.
- Look at lines near the rear axle and tank for rust or rub marks.
- Ask for a smoke test.
Wide range: this job varies a lot. Itemize your quote for a better answer.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $8 | $40 |
| Labor: 0 to 0.3 hours × $110 to $150 an hour | $0 | $45 |
| Fees: shop supplies, disposal, diagnostics | $0 | $10 |
| Total, rounded | $5 | $95 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in the US, $27.13 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
The cap costs little. A leak detection pump is a modest part but the fuel tank-area access adds labor. Line repair depends on whether the line is rusted through.
Other repairs that may be involved
| Repair | Typical range, US |
|---|---|
| Gas cap replacement | $5 to $95 |
| EVAP purge valve replacement | $80 to $240 |
| EVAP vent valve replacement | $110 to $330 |
Questions to ask the shop
- Did you do a smoke test?
- Is the repair a cap, a line or the pump?
- Is a part under recall or warranty?
Got a quote already? Check it against the range. Wondering if a recall touches this problem? See Jeep recalls by model or check a VIN.
P0456 on a Jeep: questions
Is P0456 safe to drive?
Yes. It will fail an emissions test but it is not a safety issue.
Why does my Jeep set it after off-roading?
Because dirt, rocks or water can damage vapor lines or the canister.
How much does it cost to fix P0456 on a Jeep?
The most common fix, gas cap replacement, has a typical range of $5 to $95 across the US. That is an estimate built from parts prices and local labor wages, not a quote. Your model, engine and shop move it.
P0456 on other makes
Sources
- NHTSA complaints, 2012 Jeep Wrangler
- NHTSA complaints, 2012 Jeep Grand Cherokee
- NHTSA recall lookup by VIN
Written from public NHTSA data, owner-reported patterns and general repair knowledge, in our own words. Model lists are examples, not a full list, and patterns are not a diagnosis. Prices updated October 2026. Not a repair shop, estimates only.