The reason of P165A is system wiring, connectors, or other electrical components are also subject to failure. When this code is set, it is imperative that the transmission be checked prior to further vehicle operation.
This will help to determine whether or not the malfunction is intermittent. After the codes are cleared, test drive the vehicle to see if the code returns
If the resistance level does not decrease with heat and increase as it cools, replace the sensor. If everything has checked out thus far, turn the key to the "ON" position and test for the presence of a voltage (and a ground signal) at the exhaust gas temperature/pressure (or heated oxygen) sensor electrical connector
Many vehicle applications utilize an electronically controlled valve in the automatic transmission cooler lines to regulate the flow of fluid to the cooler itself
If the fuel shutoff switch and all system circuitry checks out, suspect a defective PCM (or other related controller)
Auxiliary Emission Controls
Low Coolant Circuit
TFP Valve Position Switch-Drive Without Drive Ratio
When you put your foot down on the brakes you expect your car to quietly slow down and come to a stop. The power your foot applies on the brake pedal is assisted by hydraulic pressure. Your foot's force engages a piston and caliper with brake pads attached (bonded abrasive and heat resistance metal or ceramic) to put pressure on the rotor. P165A OBD2 specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.
How to turn off P165A check engine light ?
There are two ways to turn off the check engine light:
A repair technician can do so once repairs have been made.
The OBD II can automatically turn it off when it fails to detect the problem after several diagnostic cycles.