What does P1191 mean on a Chevy?

P1191. Intake Air Duct Air Leak. Applies to Equinox, Malibu, Traverse, Silverado, Colorado.

What causes P1191 on a Chevy?

Cracked intake air duct between MAF and throttle body Loose duct clamps drawing unmetered air Collapsed or delaminated intake resonator Missing or torn PCV fresh-air tube at the duct Warped airbox lid breaking the duct seal

How do I fix P1191 on a Chevy?

Visually flex the intake duct while the engine idles and listen for hiss Spray carb cleaner sparingly around duct joints and watch fuel trims Tighten or replace duct clamps and reseat the resonator Inspect the PCV fresh-air hose connection at the duct Replace the duct only if cracks are found, then clear and verify trims normalize

Code

P1191

Intake Air Duct Air Leak

Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: Equinox, Malibu, Traverse, Silverado, Colorado
Related: No single generic twin. See OBD Codes List

What it means

P1191. Intake Air Duct Air Leak. This Chevy-enhanced code applies to Equinox, Malibu, Traverse, Silverado, Colorado.

Findings, check these first

Cracked intake air duct between MAF and throttle body
Loose duct clamps drawing unmetered air
Collapsed or delaminated intake resonator
Missing or torn PCV fresh-air tube at the duct
Warped airbox lid breaking the duct seal

Standard procedure

Visually flex the intake duct while the engine idles and listen for hiss
Spray carb cleaner sparingly around duct joints and watch fuel trims
Tighten or replace duct clamps and reseat the resonator
Inspect the PCV fresh-air hose connection at the duct
Replace the duct only if cracks are found, then clear and verify trims normalize

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Sources and review

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Last updated 2026-09-13.

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