Hello, U codes are module/network communications codes. So, if a U0101 was stored in the engine computer (ECM/PCM) and a traction control light is on, including these other symptoms you mentioned, there is most likely going to be other codes stored in other modules. So, a full system scan should be done to see what other modules have for codes in them, it might be that something is affecting the data bus network causing these issues. At least one module is setting a communications code, and most vehicles these days have multiple networks built into them.
It also looks like this is a hybrid vehicle, correct? So having a shop scan the vehicle with a capable scan tool would be the next step, you don't want to mess around with any high voltage wiring that hybrids carry, it's enough voltage to harm a person or worse. The high voltage wires are bright orange to avoid them. Theres a few technical service bulletins listing this code which do mention the transmission control modules harness and ground locations being checked at contact locations where the harness may have rubbed threw and possibly be making contact with the engine block. That would explain why the reverse camera may not be working as well, since it's triggered on by being put into Reverse.
So, the transmission control module might not be communicating correctly, or another module on its network is sending out corrupt data packets, affecting all the modules on the high-speed data bus. When network faults like this occur, it usually affects more than one system in the vehicle, so that's probably why you are experiencing multiple issues at once. But do avoid the high voltage system if you are not trained to work on them.
Apr 30, 2025 at 3:46 PM
