Faulty EVAP vent valve (solenoid coil shorted internally); Control wire shorted to earth, often from chafed or damaged harness near the tank or rear underbody; Corroded, wet or damaged connector at the vent valve; Water, dirt or debris contamination in the vent valve or its associated pipework; Fault in the control module output driver; Previous repair or collision damage to the harness near the EVAP canister.

P0498

EVAP System Vent Valve Control Circuit Low.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
98: FaultThe specific fault in that area

What it means

P0498 means the powertrain control module has detected a low voltage condition in the control circuit for the evaporative emission (EVAP) system vent valve. The vent valve normally opens to let fresh air into the EVAP system and closes during leak tests. The module sets the code when the voltage it sees on the control circuit does not match the commanded state, which points to a short to earth, a failed valve coil or a driver fault.

Symptoms

Malfunction indicator lamp on
Difficulty filling the fuel tank, with the pump clicking off repeatedly
Fuel smell around the rear of the car or near the fuel tank
Other EVAP codes stored alongside, such as leak or purge faults
Failed emissions test
Usually no noticeable change in how the engine runs

Possible causes

Faulty EVAP vent valve (solenoid coil shorted internally)likely
Control wire shorted to earth, often from chafed or damaged harness near the tank or rear underbodylikely
Corroded, wet or damaged connector at the vent valvelikely
Water, dirt or debris contamination in the vent valve or its associated pipeworkpossible
Fault in the control module output driverrare
Previous repair or collision damage to the harness near the EVAP canisterpossible

How to diagnose

Read the stored codes and freeze frame data, then note any other EVAP codes and whether the fault is current or intermittent
Visually inspect the vent valve, its connector and the harness for damage, corrosion, water ingress or chafing, noting that the valve location varies by model
Disconnect the valve connector and check for corrosion or bent terminals, then clear the code and see if it returns
Measure the valve coil resistance and compare it with the manufacturer specification for that model
Use a bi-directional scan function, where supported, to command the valve and listen for a click or watch the commanded state
Check the control circuit for a short to earth with the module and valve disconnected, following the wiring diagram for the vehicle
Check the supply voltage and earth to the valve circuit, and only then consider the control module if the wiring and valve prove good

How to fix

Replace the EVAP vent valve if the coil resistance is out of specification or it fails the function test
Repair or replace the damaged section of wiring where a short to earth is found
Clean, dry or replace the corroded connector and terminals
Clear any contamination and replace the affected valve or pipework
Repair or replace the control module only after the wiring and valve are confirmed good and the manufacturer procedure supports it

Can I keep driving?

Low severity

The car is generally safe to drive in the short term as this fault does not normally affect engine running. Book it in soon, because the EVAP system cannot test itself and you may fail an emissions test or notice fuel vapour smells.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.