P0468 indicates the powertrain control module has detected a voltage signal from the evaporative emission purge flow sensor that exceeds the calibrated maximum threshold. This typically means the sensor circuit is shorted to voltage, the sensor has failed internally, or there is an intermittent high-resistance connection causing the signal to float high.
The signal wire may be chafed against the engine or frame and contacting a voltage source, or shorted to the 5V reference circuit, causing the PCM to see maximum voltage.
Internal short to power within the sensor can cause a constant high voltage output regardless of actual purge flow conditions.
Moisture intrusion, bent pins, or poor terminal tension at the sensor or inline connectors can create abnormal resistance that drives the signal voltage high.
A loose, broken, or corroded ground wire can cause the signal voltage to float high instead of returning to the proper low-reference level.
Rarely, the PCM's internal analog-to-digital converter or input processing circuit may incorrectly interpret a normal signal as high voltage; this should only be considered after wiring and sensor have been verified.
Yes, short-term driving is generally safe, though fuel economy may suffer slightly and evaporative emissions may increase.
No. PCM failure is an unlikely cause for this specific circuit code; thorough testing of wiring and the sensor should be completed before considering the control module.
It is a device that measures the volume or rate of fuel vapor flowing from the charcoal canister to the intake manifold during the purge cycle; not all vehicles use this specific sensor type.
Yes, an active P0468 will typically cause a failed emissions test because it indicates a malfunction in the evaporative emission control system.