Code Definition

P1309 — Rough road sensor voltage too high

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

About P1309

P1309 is a manufacturer-specific powertrain diagnostic trouble code recorded for Hyundai vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1309 is stored, the module has detected a signal or supply voltage higher than the expected operating range; 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.

P1309 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 rough road sensor, a body mounted accelerometer or G sensor, feeds the Engine Control Module a voltage representing road surface vibration so the misfire monitor can be suspended on rough ground. DTC P1309 is set on Hyundai and Kia vehicles when the ECM sees the rough road sensor signal voltage above the normal operating range for too long. A persistently high voltage typically points to the signal circuit shorting to the reference or to battery voltage, an open ground letting the signal float high, or a sensor that has failed in a high output state. As with the other rough road faults, th...

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