Thermo King SGCO 3000, Manual

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131
Mechanical Diagnosis
NOTE: This diagnosis guide applies to units equipped with TK486 engines. For major repair of TK486
engines, refer to Overhaul Manual, TK 50136.
Diagnosing Unit Conditions
Condition Possible Cause Remedy
Unit switch On; controller
display does not come on Corroded battery cable connections Clean and tighten
Batteries discharged Charge or replace batteries
Fuse SI3 open (blown) Check for short circuit and replace fuse
Defective On/Off switch Check switch
Open circuit Check 2, 2B, 2C and 8 circuits
Unit switch On (controller
display is On) but engine
does not crank Batteries discharged Charge or replace battery
Corroded battery connections Clean and tighten
Defective starter relay or open circuit Replace relay; check 2A, 8S, SR and
PSR circuits
Defective starter solenoid Replace solenoid
Defective starter Repair starter
Water in cylinders Check for hydrostatic lock. Remove
injectors and turn engine slowly
Starter motor turns but
engine does not crank Starter clutch defective Replace
Engine cranks but fails to
start Fuel solenoid not energized Check fuse SI1, 8D and 8DP circuits,
fuel pull relay (RL1), and fuel hold relay
(RL2).
Fuel solenoid valve defective or stuck Replace
No fuel or wrong fuel Fill with proper fuel
Air cleaner clogged Clean and refill oil reservoir on oil bath
air cleaner; or replace dry air cleaner
filter
Exhaust plugged Clear exhaust system
Air heater defective Replace defective air heater
Air in fuel system Bleed air
Fuel pump defective Replace pump
Incorrect timing Adjust timing
Injection nozzles defective Repair or replace nozzles
Injection pump defective Replace pump
Compression low Overhaul engine