P00178
Carrier Transicold
Warning

Check UL1

Circuit failure for cylinder unloader number 1 (UL1).

Possible causes

  • Open UL1 coil
  • Wiring short to ground in harness
  • Bent solenoid stem

Recommended actions

  • Test UL1 coil with multimeter
  • Inspect wires for abrasion
  • Verify mechanical operation of unloader

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