P0317 indicates the powertrain control module has detected that the rough road hardware input is not present or is not communicating as expected. The rough road sensor (typically an accelerometer) is used by the PCM to distinguish genuine engine misfires from vibrations caused by rough road surfaces. When this input is missing, the PCM may disable certain misfire detection functions.
The rough road sensor itself may have failed internally or may have been removed and not reinstalled during prior service. A failed sensor is the most common root cause for this code.
Chafed, broken, or corroded wiring between the rough road sensor and the PCM can interrupt the signal. Harness damage near the sensor or along the chassis routing is common.
Corroded, bent, or pushed-back pins in the sensor or PCM connector can cause an open circuit. This is especially common in vehicles exposed to moisture or road salt.
If the PCM was recently reprogrammed or replaced with an incorrect calibration that expects rough road hardware not present on that specific vehicle configuration, this code can set.
An internal fault in the PCM's input circuit for the rough road signal is rare and should only be considered after all sensor, wiring, and connector checks have been conclusively ruled out.
In most cases there is no noticeable drivability impact. The primary concern is that misfire detection may be partially disabled, which means a real misfire could go undetected and potentially damage the catalytic converter over time.
Short-term driving is generally safe, but the code should be addressed because the PCM may not detect misfires while the rough road input is unavailable. Extended operation risks undetected misfire damage to emissions components.
No. Replacing the PCM is rarely the correct fix for P0317. The vast majority of cases involve a faulty or missing rough road sensor, damaged wiring, or a connector problem. PCM replacement should be a last resort only after all other causes have been conclusively eliminated.
The rough road sensor helps the PCM tell the difference between crankshaft speed variations caused by actual engine misfires and those caused by driving over bumps. Without it, the misfire monitor can produce false readings on uneven surfaces.