P0498: EVAP System Vent Valve Control Circuit Low

The evaporative emission (EVAP) system stores fuel vapour from the tank in a charcoal canister; a purge valve lets the engine draw it off, and a vent valve opens the canister to fresh air. The vent valve is normally open and switched to ground by the module; P0449 (open), P0498 and P0499 form the newer code scheme for its circuit, used mainly by GM and Saab models with GM engines, while Ford uses P0446. P0498 means the control wire is shorted to ground: GM sees 0.5 Ω or less to ground with the driver off (20 of 25 samples), Saab below 2.6 V – MIL after two trips. The valve is then permanently energised and closed, so the tank is not vented and refuelling becomes difficult.

Low severity. Can I keep driving?Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

Symptoms

Check engine light on
Refuelling difficult, nozzle clicks off
Vacuum noise when opening the fuel cap

Most likely causes

Vent valve control wire chafed against ground (underbody, tank area)
Vent valve coil shorted internally
Corrosion or water in the connector
Driver in the engine module

What to check, in order

Start with the simplest. You can tick off each step.

Start with the fuel cap: tighten it fully and check its seal
With the connector unplugged, check whether the signal wire is making contact with ground.
Inspect the hoses and connections around the tank and the charcoal canister
Use the scanner to test the purge and vent solenoid valves
Run a smoke test to find small leaks

Good to know

Repair difficulty: easy
It affects emissions.

What each character of P0498 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
4: Emissions
98: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0498?

Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

What causes code P0498?

The most common causes are: vent valve control wire chafed against ground (underbody, tank area); vent valve coil shorted internally; corrosion or water in the connector.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.