Trane air conditioner displays E5 and will not run or stops shortly after starting.

Safety first: Turn off power at the main breaker and outdoor disconnect. High voltage and stored energy in capacitors can be dangerous.

• Visual inspection: Remove the outdoor unit service panel. Look for burnt wires, melted insulation, or signs of arcing near the compressor terminals and contactor.
• Check capacitor condition: Inspect the dual run capacitor for bulging or leaks. Replace if deformed, using the exact µF and voltage rating specified on the Trane unit data plate.
• Inspect contactor: Examine the contactor contacts for heavy pitting or welding. Replace if badly worn, as this can cause overheating and overcurrent.
• Reset and test: After replacing any obviously failed components, restore power and call for cooling. If the compressor still trips immediately and E5 returns, the compressor may be mechanically locked or electrically shorted.

Compressor overcurrent issues often require professional diagnosis with an ammeter and megohmmeter. Contact a Trane technician for compressor testing and possible replacement.