Common Toyota Denso ECU problems include faulty wiring or poor connections, sensor malfunctions, and firmware updates issues 1. A malfunctioning ECU can cause various symptoms such as reduced power, stalling, rough idle, decreased fuel efficiency, and erratic instrument cluster behavior 2. Additionally, transmission issues like harsh shifting and delayed shifts may also indicate ECU problems 2. Rodent damage, bad past repairs, and worn mechanical parts can also contribute to ECU malfunctions 3.
If you suspect ECU issues, it's essential to retrieve error codes using a diagnostic scanner to identify the underlying problems 1