U0163 indicates that the engine control module (PCM/ECM) has lost communication with the navigation control module over the vehicle's network. This typically points to a wiring, power, or module fault rather than a PCM failure.
Damaged, corroded, or loose wires in the Controller Area Network (CAN) bus between the PCM and navigation module are the most common cause.
Internal failure of the navigation module itself can prevent it from communicating on the network.
A weak battery, loose battery terminals, or a bad ground connection can disrupt module communication.
Improperly installed aftermarket audio, navigation, or telematics equipment can damage the network or cause communication errors.
While possible, the PCM is rarely the cause. This should only be considered after all other possibilities are ruled out.
Not necessarily. Wiring issues, poor connections, or low battery voltage are more common causes. Only replace the module after thorough electrical testing confirms it is defective.
Yes, in most cases the vehicle will still drive normally. However, the navigation system will not work, and the check engine light will stay on. If other communication codes are present, drivability may be affected.
No. The PCM is rarely at fault for this code. Many drivers are incorrectly told to replace the PCM, but the issue is almost always in the navigation module circuit or the module itself.
Use a professional scan tool to attempt direct communication with the module. If the tool cannot establish contact and all wiring, power, and ground tests pass, the module is likely faulty.