# P0498: Evaporative Emission System Vent Valve Control Circuit Low **Verdict:** Safe to drive Emissions - Generic OBD-II code, applies to all gasoline cars and light trucks sold in the US since 1996. - **Typical cost:** $100-$450 - **Urgency:** Keep driving - **Most likely:** Failed vent valve or shorted wiring - **DIY?:** Steps 1-3 ## Quick answer P0498 means the engine computer has found that the voltage on the EVAP vent valve control circuit is lower than it should be. The vent valve lets the fuel vapor system breathe fresh air and closes during leak tests. The usual causes are a wire shorted to ground, a failed vent valve, or a corroded connector near the charcoal canister. ## What does P0498 mean? The EVAP vent valve, sometimes called the canister vent solenoid, sits on or near the charcoal canister, usually under the vehicle close to the fuel tank. It stays open most of the time so the canister can draw in fresh air during purging and let air out as the tank fills. When the engine computer runs a leak test, it energizes the valve to close it and seal the system. On most designs the valve receives power through a fused feed, and the computer controls the ground side. The computer watches the control wire and knows what voltage to expect when the valve is switched off. P0498 sets when that voltage reads too low, which on many vehicles means the control wire is shorted to ground, the power feed is open, or the coil has failed, though the exact logic varies by maker. It can set on the first trip, and leak tests are usually suspended until it is fixed. ## What are the symptoms of P0498? - Check engine light on with normal driving - EVAP monitor not ready, or a failed emissions test - Fuel nozzle clicking off early when refueling if the valve stays closed - Other EVAP codes such as P0446 or P0449 stored at the same time - Blown fuse affecting other parts on the same circuit on some vehicles ## What causes P0498? Ranked from most to least likely. Check them in this order: the cheap, common causes first. 1. **Failed vent valve coil** (most common). The vent valve's solenoid lives in one of the harshest spots on the vehicle, near the fuel tank and open to spray and dust. Water or debris can get inside, and the coil can short or open after years of heat cycles. Measuring the coil's resistance and comparing it with the specification confirms a failed valve. 2. **Chafed wire shorted to ground** (common). The vent valve harness runs along the frame to the rear of the vehicle, exposed to stones, water, and road salt. Chafed insulation lets the control wire touch metal and pulls the voltage low. This is especially common on older trucks and SUVs and on vehicles driven on gravel or salted winter roads. 3. **Corroded or water-filled connector** (common). The connector at the vent valve takes road spray, and its seals harden with age. Water and corrosion inside can create a low-resistance path or a poor contact that the computer reads as a low circuit. Cleaning the pins and fitting a new connector pigtail often fixes the code without replacing the valve. 4. **Blown fuse or open power feed** (less common). If the fuse or the feed wire to the vent valve fails, the control wire loses its voltage and reads low on many designs. Since that fuse is often shared with other parts, a short in another component can blow it too. Check the fuse and test for battery voltage at the valve with the key on. 5. **Engine computer driver fault** (rare). A shorted vent valve can overload the engine computer's internal driver for that circuit, so the code stays even after the valve is replaced. This is rare. A shop should confirm that the wiring and valve are good, and check for software updates, before repairing or replacing the computer. ## How do you diagnose P0498? 1. Check related fuses and note any other circuit codes stored at the same time. 2. Locate the vent valve, usually at the canister near the fuel tank, and inspect its connector and harness. 3. Measure the valve's coil resistance and compare it with the service manual value. 4. With the key on, check for battery voltage at the connector, then check the control wire for a short to ground. 5. Command the valve closed and open with a scan tool and confirm it clicks and the circuit reads correctly. ## How do you fix P0498, and what does it cost? | Fix | Typical cost | What it involves | | --- | --- | --- | | Repair chafed wiring or connector | $100-$350 | Includes tracing the short along the frame. | | Replace EVAP vent valve | $120-$450 | Higher when the valve is sold only with the charcoal canister. | ## Is it safe to drive with P0498? > **Safe to drive.** Yes, P0498 is safe to drive with, because it affects the emissions system rather than engine performance. If the fuel nozzle keeps clicking off when you refuel, the valve may be stuck closed, which makes filling up slow. Fix it before an emissions test. ## Will P0498 fail an emissions test? P0498 fails an OBD-based emissions test in most states while the check engine light is on. Because the vent valve must close for the EVAP leak tests, the EVAP monitor usually stays not ready until the circuit is repaired. Clearing the code right before a test leaves the monitor incomplete, so repair it and drive several days first. ## After the repair: clearing P0498 Clear the code after the repair and command the vent valve closed and open with a scan tool to confirm it responds. Then drive normally for several days, including overnight cool-downs, so the EVAP leak test can run. The fix worked when P0498 stays away, refueling is normal, and the EVAP monitor reads ready. ## How to prevent P0498 - Rinse the underbody in winter to slow corrosion around the canister and its wiring. - Make sure harness clips under the car are refastened after any tank or exhaust work. - Avoid deep standing water and rough gravel where possible, since both batter the canister area. - Stop fueling at the first click so liquid fuel does not soak the canister and vent valve. ## Codes often seen with P0498 - [P0446](/codes/p0446): Evaporative Emission System Vent Control Circuit - [P0449](/codes/p0449): Evaporative Emission System Vent Valve/Solenoid Circuit - [P0455](/codes/p0455): Evaporative Emission System Leak Detected (large leak) - [P0442](/codes/p0442): Evaporative Emission System Leak Detected (small leak) - [P0440](/codes/p0440): Evaporative Emission System ## Frequently asked questions ### Can I drive with a P0498 code? Yes, P0498 does not affect how the engine runs, so it is generally safe to drive. You will keep the check engine light on and will likely fail an emissions test. If refueling becomes difficult because the nozzle keeps clicking off, have the vent valve checked soon. ### What does EVAP vent valve control circuit low mean? It means the voltage on the wire the engine computer uses to control the vent valve is lower than expected. On many vehicles that points to a wire shorted to ground, a failed valve coil, or a lost power feed. It is an electrical fault, not a vapor leak. ### How much does it cost to fix P0498? Most P0498 repairs cost $100 to $450 at an independent shop. Repairing chafed wiring or a corroded connector runs about $100 to $350. A new vent valve costs $120 to $450 installed, at the higher end when the valve is only sold together with the charcoal canister. ### Where is the EVAP vent valve? On most vehicles it is mounted on or near the charcoal canister, which usually sits under the car close to the fuel tank. On some models it is near the rear axle or behind a splash shield. A parts diagram for your exact model shows its location. ### What is the difference between P0498 and P0449? P0449 is a general fault in the vent valve circuit, while P0498 specifically means the circuit voltage reads low. Some makers use one code and some the other, depending on how their software checks the circuit. The testing steps, starting at the valve and its wiring, are similar. ### Can a bad vent valve make it hard to fill the gas tank? Yes, if the vent valve stays closed, air cannot escape the tank as fuel goes in, so the pump nozzle keeps clicking off. With some faults behind P0498, such as a control wire shorted to ground, the valve can stay energized and closed. A clogged vent filter does the same. ### Can I replace an EVAP vent valve myself? Often yes, if you can reach it safely under the car. Most valves unclip or unbolt from the canister with one connector and a hose. Support the vehicle on stands, never just a jack, and inspect the harness while you are there, since wiring is a common cause too. ### Will P0498 fail an emissions test? Yes, in most states P0498 fails an OBD-based test while the light is on. The EVAP monitor also cannot run its leak test until the vent valve works, so it may show not ready. Repair the circuit and drive several days before testing. ### Why does P0498 come back after replacing the vent valve? If the code returns, the problem is usually in the wiring, connector, or fuse rather than the valve. A chafed wire under the car may only short when wet or when the body flexes over bumps. Rarely, the engine computer's driver circuit is damaged and needs repair. ### Does P0498 mean there is a fuel leak? No, P0498 is an electrical circuit code and does not mean fuel is leaking. However, until it is fixed, the computer cannot test the EVAP system for vapor leaks. If you smell raw fuel or see drips under the car, have that checked separately and promptly. ## Sources - [SAE J2012: Diagnostic Trouble Code Definitions](https://www.sae.org/standards/content/j2012_201812/) - [EPA: On-Board Diagnostics (OBD)](https://www.epa.gov/state-and-local-transportation/vehicle-emissions-board-diagnostics-obd) ## Other emissions codes - [P0443 Evaporative Emission System Purge Control Valve "A" Circuit](https://diagxcar.com/codes/p0443) - [P0446 Evaporative Emission System Vent Control Circuit](https://diagxcar.com/codes/p0446) - [P0449 Evaporative Emission System Vent Valve/Solenoid Circuit](https://diagxcar.com/codes/p0449) - [P0451 Evaporative Emission System Pressure Sensor/Switch "A" Circuit Range/Performance](https://diagxcar.com/codes/p0451) - [P0452 Evaporative Emission System Pressure Sensor/Switch "A" Circuit Low](https://diagxcar.com/codes/p0452) - [P0455 Evaporative Emission System Leak Detected (large leak)](https://diagxcar.com/codes/p0455) - [P0456 Evaporative Emission System Leak Detected (very small leak)](https://diagxcar.com/codes/p0456) - [P0457 Evaporative Emission System Leak Detected (fuel cap loose/off)](https://diagxcar.com/codes/p0457) - [P0491 Secondary Air Injection System Insufficient Flow Bank 1](https://diagxcar.com/codes/p0491) - [P0496 Evaporative Emission System High Purge Flow](https://diagxcar.com/codes/p0496) --- Source page: https://diagxcar.com/codes/p0498 Updated: 2026-11-03 General information, not a substitute for a qualified mechanic.