What does P1134 mean on a Chevy?

P1134. HO2S Transition Time Ratio Bank 1 Sensor 1. Applies to Silverado, Sierra, Tahoe, Yukon, Malibu, Colorado, TrailBlazer.

What causes P1134 on a Chevy?

Aging Bank 1 Sensor 1 oxygen sensor with slow rich-to-lean transitions Contaminated HO2S element from coolant consumption or improper RTV sealant Exhaust leak ahead of the Bank 1 upstream sensor skewing transition timing HO2S heater feed fault delaying closed-loop response on cold starts

How do I fix P1134 on a Chevy?

Monitor HO2S Bank 1 Sensor 1 voltage transitions on a Tech2 or GDS2 at 1200-3000 RPM Rule out exhaust leaks ahead of the sensor before condemning it Inspect the sensor tip for white powdery silicon contamination and fix the source first Test HO2S heater ignition feed and ground circuits for intermittents Replace Bank 1 Sensor 1 only on failed transition-time tests, then clear and road test

Code

P1134

HO2S Transition Time Ratio Bank 1 Sensor 1

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

What it means

P1134. HO2S Transition Time Ratio Bank 1 Sensor 1. This Chevy-enhanced code applies to Silverado, Sierra, Tahoe, Yukon, Malibu, Colorado, TrailBlazer.

Findings, check these first

Aging Bank 1 Sensor 1 oxygen sensor with slow rich-to-lean transitions
Contaminated HO2S element from coolant consumption or improper RTV sealant
Exhaust leak ahead of the Bank 1 upstream sensor skewing transition timing
HO2S heater feed fault delaying closed-loop response on cold starts

Standard procedure

Monitor HO2S Bank 1 Sensor 1 voltage transitions on a Tech2 or GDS2 at 1200-3000 RPM
Rule out exhaust leaks ahead of the sensor before condemning it
Inspect the sensor tip for white powdery silicon contamination and fix the source first
Test HO2S heater ignition feed and ground circuits for intermittents
Replace Bank 1 Sensor 1 only on failed transition-time tests, then clear and road test

Look up another code

Press / to jump to the box. Chevy-enhanced powertrain, body, chassis and network codes.

Sources and review

Review: no source links are recorded for this entry.

Last updated 2026-09-19.

Report a correction for P1134. Include your vehicle, the issue and a source if you have one.