Toyota Tundra 2005 Service - Repair - Maintenance page 3494

5. ECU (ELECTRONIC CONTROL UNIT)
Many ECUs are mounted in this vehicle.
Take the following precautions during body repair to prevent damage to the ECUs.
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Before starting electric welding operations, disconnect the negative (-) terminal cable from the battery.
When the negative (-) terminal cable is disconnected from the battery, memory of the clock and audio systems will be
cancelled. So before starting work, make a record of the contents memorized by each memory system. Then when work is
finished, reset the clock and audio systems as before.
When the vehicle has tilt and telescopic steering, power seat and outside rear view mirror, which are all equipped with
memory function, it is not possible to make a record of the memory contents.
So when the operation is finished, it will be necessary to explain this fact to the customer, and request the customer to
adjust the features and reset the memory.
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Do not expose the ECUs to ambient temperatures above 80SC (176SF).
NOTICE: If it is possible the ambient temperature may reach 80S (176SF) or more, remove the ECUs from the vehicle
before starting work.
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Be careful not to drop the ECUs and not to apply physical shocks to them.
INTRODUCTION - Handling Precautions on Related Components IN-9