Error Code P085A is defined as Gear Shift Control Module “B” Communication Circuit. Error Code P085A is a generic trouble code, meaning it applies to all cars with the OBD-II system, especially those made from 1996 up to the present. Specifications on the definition, troubleshooting, and repairs, of course, vary between make, model, and powertrain configuration.
The PCM (powertrain control module, also known as ECM or engine control module) monitors the gear shift control module. It sets the error code if it sees a problem communicating with the gear shift control module.
Check Engine light or Service Engine Soon Warning light on.
Check for the possible causes listed above; inspect all related wirings, connectors, and harness.
Then, check for damaged components such as bent, broken, pushed out, and corroded connector pins.
Make sure you test drive your 2008 Saturn Vue after completing any repairs to see if the condition is fixed.
Don’t forget to erase all P code(s) first before taking your 2008 Saturn Vue for a test drive. This will turn the Check Engine light off, which will give you a good idea if your repairs worked as the Check Engine light will be activated if the problem remains.
This is a serious and complicated problem, which means it must be addressed by an expert technician as soon as possible.