Diagnostic trouble code P0468 indicates that the evaporative emissions (EVAP) system is detecting a high input signal from the purge flow sensor circuit. This code is typically caused by a faulty purge flow sensor, but can also be caused by wiring issues or a problem with the powertrain control module (PCM).
Here are the steps to diagnose and repair the issue:
- Check the wiring and connectors for damage, wear, or corrosion. Repair or replace as necessary.
- Check the resistance of the purge flow sensor. Compare the reading to the manufacturer's specifications. If it is outside of the specified range, replace the sensor.
- Check the power and ground circuits to the purge flow sensor. Use a multimeter to test for voltage and continuity. Repair or replace as necessary.
- Check the PCM for a software update that may address the issue. If an update is available, follow the manufacturer's instructions to install it.
- If the issue is not resolved after following the above steps, replace the PCM.
It is recommended to have a professional mechanic perform these steps to properly diagnose and repair the issue.
