What Does P1426 Mean?
The evaporative emission system's tank ventilation valve (purge valve or vent valve) has an open circuit detected by the ECM. This means electrical continuity is broken between the ECM and the valve, preventing proper fuel vapor control.
Common Causes
35%
Damaged or broken wiring harness to the tank ventilation valve
30%
Failed tank ventilation/vent solenoid valve
20%
Corroded or disconnected electrical connector at the valve
10%
ECM internal driver circuit failure
5%
Blown fuse or fusible link in the EVAP control circuit
Diagnostic Steps
1
Step 1: Visually inspect the tank ventilation valve and connector for damage, corrosion, or disconnection
2
Step 2: Check for blown fuses in the EVAP control circuit
3
Step 3: Measure resistance across the valve solenoid terminals (typically 20-40 ohms when disconnected)
4
Step 4: Test continuity of wiring between ECM connector and valve connector using a wiring diagram
5
Step 5: If wiring and valve are good, test ECM output voltage/ground signal to the valve during commanded operation
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
The evaporative emission system's tank ventilation valve (purge valve or vent valve) has an open circuit detected by the ECM. This means electrical continuity is broken between the ECM and the valve, preventing proper fuel vapor control.
The most common cause of P1426 (Tank Ventilation Valve Open Circuit) is: Damaged or broken wiring harness to the tank ventilation valve
Typical repair costs for P1426 range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive but will fail emissions testing. Fuel vapors may not be properly controlled, causing odor.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1426 to identify the root cause.
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Quick Info
Category
Powertrain
System
Evaporative Emissions
Difficulty
Type
Manufacturer
Recommended Tools
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