Code Definition

P1134 — 5 Volt Reference 2 Voltage Low, or O2 Sensor Bank 1 Sensor 1

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1134

P1134 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1134 is stored, the module has detected a signal or supply voltage lower than the expected operating range; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; and a sensor-related fault — the reported value from the named sensor is out of spec.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1134 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This General Motors specific code carries two published definitions, a low voltage condition on the number 2 five volt reference circuit, or a fault relating to the Bank 1 Sensor 1 oxygen sensor. Many GM PCMs supply more than one regulated 5V reference bus to share sensor loads, and Reference 2 feeds a group of sensors such as the MAP, throttle position or pressure sensors depending on the platform. P1134 in the reference form sets when the PCM measures the 5V Reference 2 circuit pulled below its expected value, which usually means a short to ground or an overloaded reference shared by several...

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