Handling Of Electronic Parts

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Do not open the cover or case of the ECU unless absolutely necessary. If the IC terminals are touched, the IC may be rendered inoperative by static electricity.
To disconnect electronic connectors, pull the connector itself, not the wires.

Fig 1: Precaution While Handling Electronic Parts
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Be careful not to drop electronic components, such as sensors or relays. If they are dropped on a hard surface, they should be replaced.
When cleaning the engine with steam, protect the electronic components, air filter and emission-related components from water.
Never use an impact wrench to remove or install temperature switches or temperature sensors.
When checking the resistance of a wire connector, insert the tester probe carefully to prevent terminals from bending.