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Thermo King SR Controller Alarm Codes (00, 04, 17)

Likely causes

Alarm 00 — High-pressure switch trip: poor condensing

Check: Check condenser coil fin blockage → verify cooling fan rotation and current → confirm discharge pressure normal value

What to do: Reverse-blow condenser coil fins with air gun → replace cooling fan motor if faulty → reset alarm and restart

Alarm 04 — Low-pressure switch trip: refrigerant shortage or evaporator over-frost

Check: Measure refrigerant pressure — if suction pressure abnormal check for leaks; visually inspect evaporator for over-frosting

What to do: Repair refrigerant leak and recharge → manually defrost evaporator if over-frosted → verify defrost timer settings

Alarm 17 — Engine high temp: low coolant or broken fan belt

Check: Check coolant level → inspect fan belt tension and condition → verify radiator fin cleanliness

What to do: Top up coolant → replace fan belt → clean radiator fins → pressure test entire cooling system

Field tip

Identifying repeating alarm code patterns from history is key — access codes with SET+ZONE 3 seconds and always photograph the alarm list for service records.

All 565 cases work offline in R-Pro, with error codes for 62 brands and P-T data for 108 refrigerants.

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