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P0171 and P0174 Fault Diagnosis for 2001 V6 3.8L Camaro - Vacuum System Issue?

Model: 2001 V6 3.8 Camaro Fault Code: P0171 Posted: 2007-07-24 11:27

Some suggest replacing the brake booster and check valve as part of the vacuum system to resolve the P0171 and P0174 lean mixture codes in my 2001 V6 3.8L Camaro. While this may address a vacuum leak, I'm unsure if it's the root cause. The fuel trims remain off-normal, so further diagnostics are needed.

Related fault codes

P0171P0174

Comments (2)

Anonymous 2007-07-24 11:34

If the brake booster were the issue, simply plugging the vacuum line should resolve it — and the fuel trim values should normalize. I recommend checking fuel pressure as well to rule out other engine performance factors.

Anonymous 2007-07-25 15:31

Confirmed: the root cause was a vacuum leak in the brake booster. After repair, both P0171 and P0174 codes cleared. My braking has improved significantly — now I barely tap the brakes and stop instantly. No more lean mixture warnings.