System: Powertrain (P-Code)
SAE Standard (Generic)
Family: EVAP Refueling Vapor Valve Circuit
Code P04B4: Refueling Vapor Control Valve Stuck Closed
Diagnostic & Technical Explanation
Code P04B4 (Refueling Vapor Control Valve Stuck Closed) sets when the ECM detects an open, shorted, out-of-range, or mechanically stuck condition from the refueling vapor control valve used by the onboard refueling vapor recovery (ORVR) system to route fuel vapor to the canister only during refueling. Causes are a failed valve solenoid coil, a corroded connector, a valve stuck open/closed from fuel-vapor gum buildup, or damaged wiring to the valve.
First-listed procedure
Rank #1
Inspect and reseat the refueling vapor control valve connector
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 3 procedure(s) are in the licensed dataset. Ordering context.
Full family: EVAP Refueling Vapor Valve Circuit
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)