Fuel Trim Cylinder Balance Bank 2

What this code means

The PCM detected a rich or lean cylinder-to-cylinder air/fuel ratio imbalance on Bank 2. This is the Bank 2 counterpart to P1174 and the underlying causes are identical. The two codes frequently appear together.

Symptoms

• Check Engine Light
• Rough idle
• Poor fuel economy
• Hesitation during acceleration
• Intermittent misfires
• Engine stalling (severe cases)

Common causes

• Clogged or restricted fuel injector(s)
• Faulty upstream O2 sensor Bank 2
• Vacuum leak on Bank 2
• Dirty MAF sensor
• Cylinder misfire on Bank 2
• AFM lifter failure (V8 engines)

Diagnostic steps

1. Check fuel trim values with scan tool
2. Perform injector balance test
3. Inspect for vacuum leaks
4. Clean or replace MAF sensor
5. Test upstream O2 sensor Bank 2
6. Check for cylinder misfires

Repair notes

Same diagnostic approach as P1174. Clogged injectors are a common GM issue per TSB #03-06-04-030F. Try high-octane fuel with injector cleaner additive first.

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