TK 56433-5-MM-EN
11
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.
