P20EE: SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1

Severity

Medium

System

Powertrain

Last reviewed: Jan 1, 0001 Last updated: Jan 1, 0001

Methodology: We combine code standards with complaint and reliability patterns, then review for clear, vehicle-first diagnosis steps.

Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).

Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.

What Does P20EE Mean?

P20EE is a diagnostic trouble code indicating: SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P20EE

⚠️ Check Engine Light (MIL) illuminated
⚠️ SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1 not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Faulty SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1
🔍 Wiring or connector issue in SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1 circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does P20EE mean?

P20EE indicates: SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1. The vehicle's computer has detected that the SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1 is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P20EE?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P20EE for extended periods may cause additional problems.

How much does it cost to fix P20EE?

Repair costs for P20EE typically range from $80 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Inspect SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1 and related wiring
🔧 Replace faulty SCR NOx Catalyst Efficiency Below Threshold Bank 1 Catalyst 1

1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.