TK 61555-2-MM-EN
13
Microprocessor Service Precautions
Take precautions to prevent electrostatic discharge when servicing the microprocessor and its
related components. Even tiny amounts of current can severely damage or destroy electronic
components.
Observe the following precautions when servicing a microprocessor control system to avoid
damaging electronic components. Refer to the appropriate microprocessor diagnosis manual for
more information.
•
If the microprocessor has a power switch, turn it OFF before connecting or disconnecting the
battery.
•
Disconnect power to the unit.
•
Avoid wearing clothing that generates static electricity (wool, nylon, polyester, etc.).
•
Wear a wrist strap (P/N 204-622 or equivalent) with the lead end connected to the
microprocessor’s ground terminal. These straps are available from most electronic
equipment distributors. DO NOT wear these straps with power applied to the unit.
•
Avoid unnecessary contact with the electronic components.
•
Store and ship electronic components in antistatic bags and protective packaging.
•
Leave electronic components in their antistatic packing materials until you’re ready to use
them.
•
After servicing any electronic components, check the wiring for possible errors before
restoring power to the unit.
•
Never use a battery and a light bulb to test circuits on any microprocessor-based equipment.
Welding Precautions
Take precautions before electrically welding any portion of the unit or the vehicle to which it is
attached. Verify that welding currents are not allowed to flow through the unit’s electronic
circuits.
Observe the following precautions when welding to avoid damaging electronic components.
•
If the microprocessor has a power switch, turn it OFF before connecting or disconnecting the
battery.
•
Disconnect power to the unit.
•
Disconnect all wire harnesses from the microprocessor. Disconnect the ECU and the battery
charger if so equipped.
•
If there are any electrical circuit breakers in the control box, switch them OFF.
•
Close the control box.
•
Components that could be damaged by welding sparks should be removed from the unit.
•
Use normal welding procedures, but keep the ground return electrode as close to the area
being welded as practical. This will reduce the likelihood of stray welding currents passing
through any electronic circuits.
