U0298 indicates that the engine control module (PCM/ECM) has lost communication with the DC-DC converter control module, which manages voltage conversion between high-voltage traction battery and low-voltage electrical system in hybrid/electric vehicles. This code typically points to a network or power supply issue rather than a failed PCM.
Corrosion, broken pins, or damaged harness between the module and CAN bus or power/ground circuits are the most common cause.
A break or short in the Controller Area Network (CAN) high/low wires can prevent communication with the DC-DC converter module.
Missing 12V power or ground at the module due to blown fuse, relay, or corroded connection will cause loss of communication.
Internal module failure (e.g., water damage, component burnout) can stop it from communicating on the network.
Insufficient voltage can disrupt module operation and network communication, especially in hybrid systems.
A genuine PCM failure is uncommon for this code; it should only be considered after all other causes are ruled out.
Almost never. U0298 is a communication code, and the PCM is usually the module reporting the fault, not the cause. The issue is almost always in the DC-DC converter module itself, its wiring, or its power/ground supply.
Yes, a weak or failing 12V battery can cause intermittent communication loss with modules, including the DC-DC converter. Always check battery voltage and condition before replacing any module.
Yes, this code specifically refers to the DC-DC converter control module, which is a component in hybrid and electric vehicles that steps down high-voltage traction battery power to charge the 12V battery and run low-voltage accessories.
It depends. If the vehicle still operates normally, short trips may be possible, but the 12V battery may not charge properly, leading to a stall or no-start. It's best to diagnose and repair promptly to avoid being stranded.