P1166 — Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded

What Does P1166 Mean?

P1166 is a manufacturer-specific diagnostic trouble code: Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded. This code applies to VOLKSWAGEN, ACURA, HONDA, INFINITI vehicles. Unlike generic OBD-II codes, manufacturer-specific codes are defined by the vehicle maker and may only apply to certain makes and models.

Symptoms of P1166

⚠️ Check Engine Light (MIL) illuminated
⚠️ Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded not functioning as expected
⚠️ Related system may be in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Faulty Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded
🔍 Wiring or connector issue in Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded circuit
🔍 Related mechanical or electrical fault
🔍 ECM/PCM issue (rare)

Frequently Asked Questions

What does P1166 mean?

P1166 indicates: Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded. The vehicle's computer has detected that the Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P1166?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P1166 for extended periods may cause additional problems.

How much does it cost to fix P1166?

Repair costs for P1166 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 Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded and related wiring
🔧 Replace faulty Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded

1
Find your vehicle above
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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.

P1166: Bank 1 Long Term Fuel Trim Range 2 Upper Rich Limit Exceeded