Chevrolet P1134: HO2S-11 (Bank 1 Sensor 1) Transition Time Ratio

Is your scanner showing Chevrolet P1134?
No worries. We'll show you what it means and how to deal with it.

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Randy Worner

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Chevrolet P1134: HO2S-11 (Bank 1 Sensor 1) Transition Time Ratio

OVERVIEW

Severity

Medium

DIY Difficulty Level

Intermediate

Repair Cost

$100-$200

Can I Still Drive?

Yes (Short-term only)

What Does The Chevrolet P1134 Code Mean?

The PCM continuously monitors the heated oxygen sensor (H02S) activity. The PCM counts the number of times that the H02S responds from rich to lean and from lean to rich and adds the amount of time it took to complete all transitions during the 100 second test period. With this information, an average time for all transitions can be determined. The PCM then divides the rich to lean average by the lean to rich average to obtain a ratio. If the H02S transition time ratio is not within range, OTC P1134 will be set, indicating that the oxygen sensor is not responding as expected to changes in exhaust oxygen content.

What Are The Symptoms Of The Chevrolet P1134 Code?

The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
The PCM will store conditions which were present when the OTC set as Freeze Frame/Failure Records data.

What Are The Potential Causes Of The Chevrolet P1134 Code?

Below are some potential causes of this DTC:

Air leaks present in the exhaust manifold or the exhaust pipes
Fuel pressure is too high (i. e. , causing a rich air fuel mixture)
HO2S may be contaminated (due to improper fuel or silicone)
HO2S signal high or low reference circuit has high resistance

How Can You Fix The Chevrolet P1134 Code?

Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.

Poor terminal connection

Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.

Damaged harness

Inspect the wiring harness for damage. If the harness appears to be OK, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display may indicate the location of the fault.