K1O Factory-verified

Chevrolet · Regular Production Option

Engine air filtration monitor

Years 2022–27 Models 7 Factory citations 31

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Also described as Filter monitor, engine airAir filtration monitoringEngine air filter monitorEngine, air filtration monitor

Also documented for Buick Cadillac GMC

Documented applications

Blazer — C1XX (2019–2026)

2025–2026 Factory-verified

2LT, 3LT, RS: S; Premier: S (2025 only); letter O in the code as GM prints it; GM prints no zero form

GM factory document — 2025 chevrolet blazer fleet order guide rpo codes, p.1.
GM factory document — 2025 chevrolet blazer fleet order guide, p.8.
GM factory document — 2026 chevrolet blazer fleet order guide rpo codes, p.1.
GM factory document — 2026 chevrolet blazer fleet order guide, p.6.

Colorado — Third generation (2023–2027)

2023–2027 Factory-verified

S on all trims

GM factory document — 2023 chevrolet 23colorado electrical body builder, p.11.
GM factory document — 2024 chevrolet 24colorado electrical body builder manual 18272478 2023oct09, p.12.
GM factory document — 2025 chevrolet colorado fleet order guide, p.49.
GM factory document — 2026 chevrolet colorado fleet order guide, p.56.
GM factory document — 2027 chevrolet colorado fleet order guide, p.54.

Silverado HD (T1XX, 2020–2027)

2023, 2025–2027 Factory-verified

only in: 2500 HD, 3500 HD, 3500 HD chassis cab

GM factory document — 2023 chevrolet 23silverado 2500 3500hd electrical body builder sm en us 2022oct12, p.11.
GM factory document — 2025 chevrolet silverado 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 chevrolet silverado 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2027 chevrolet silverado 2500 hd retail and fleet fleet order guide rpo codes, p.1.

Suburban — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2025 chevrolet new suburban fleet order guide, p.7.
GM factory document — 2026 chevrolet suburban fleet order guide, p.7.
GM factory document — 2027 chevrolet suburban fleet order guide, p.7.
GM factory document — 2022 chevrolet 22 suburban tahoe electrical body builder sm u 2021oct08, p.11.
GM factory document — 2023 chevrolet 23 suburban tahoe electrical body builder sm en us 2022sep13, p.11.
GM factory document — 2026 chevrolet suburban tahoe electrical body builder manual service manual 2026 en us, p.7.

Tahoe — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2025 chevrolet new tahoe retail and fleet fleet order guide, p.6.
GM factory document — 2026 chevrolet tahoe retail and fleet fleet order guide, p.7.
GM factory document — 2027 chevrolet tahoe retail and fleet fleet order guide, p.7.
GM factory document — 2027 chevrolet tahoe police package and special service fleet order guide, p.6.
GM factory document — 2022 chevrolet 22 suburban tahoe electrical body builder sm u 2021oct08, p.11.
GM factory document — 2023 chevrolet 23 suburban tahoe electrical body builder sm en us 2022sep13, p.11.
GM factory document — 2026 chevrolet suburban tahoe electrical body builder manual service manual 2026 en us, p.7.

Trailblazer — First generation, VSS-F (2021–2027)

2025–2027 Factory-verified

all trims: S

GM factory document — 2025 chevrolet trailblazer fleet order guide, p.7.
GM factory document — 2026 chevrolet trailblazer fleet order guide, p.7.
GM factory document — 2027 chevrolet trailblazer limited fleet order guide, p.8.

Trax — Second generation, VSS-F (2024–2026)

2025–2026 Factory-verified

all trims: S; the code is printed with a letter O; GM prints no zero form

GM factory document — 2025 chevrolet trax fleet order guide, p.8.
GM factory document — 2026 chevrolet trax fleet order guide, p.8.

This page aggregates every documented appearance of K1O in the Chevrolet reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.