Code Definition

P1261 — Cylinder #1 High To Low Side Short

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

About P1261

P1261 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1261 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; a signal or supply voltage lower than the expected operating range; and a signal or supply voltage higher than the expected operating range.

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.

P1261 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

The Powertrain Control Module (PCM) fires each fuel injector using a high side driver that supplies voltage and a low side driver that completes the circuit to ground. DTC P1261 sets when the PCM detects a short between the high side and low side of the cylinder 1 injector circuit, meaning an unwanted low resistance path is allowing current to flow when it should not. To protect the output the PCM may shut down the affected injector driver, and because injectors are often grouped on a shared driver, more than one cylinder can be affected. The driver typically notices a misfire on cylinder 1, r...

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