P20F6Reductant Injection Valve Stuck Open (Bank 1 Unit 1)
The DEF injection valve at bank 1 unit 1 does not close when commanded — DEF flows continuously into the SCR. Risk of crystallisation in the catalyst and over-dosing.
Can I keep driving? NO
STOP the vehicle in a safe place. Continuing to drive may cause serious engine damage or put your safety at risk.
Sistema Afectado
Motor · Powertrain
La falla pertenece al grupo motopropulsor (motor y gestión electrónica).
Espacio para vendedores de repuestos
Aún no hay un anunciante en este espacio.
Symptoms You Will Notice
What you may observe when this code appears
- Check engine light or NOx warning on AdBlue/DEF level or quality warning Possible no-start countdown after ignore period Failed emissions inspection (NOx)
Possible Causes
The components or conditions that trigger this code
- 1Valve seat eroded or contaminated Valve plunger seized open Carbon or debris buildup preventing free movement
How to Fix It — Step by Step
Recommended diagnostic and repair procedure
- 1Difficulty: hard. Estimated time: 1-4 hours. Estimated cost: €200-€
- 2Professional repair recommended
Note: This information is for general reference. For precise diagnostics and safety repairs, always consult a certified mechanic.
Estimated Cost
Approximate range in USD (varies by region and shop)
Varies by diagnosis
* Diagnosis only: $50–$150
Quick Info
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