Indoor unit shows E1 and the system will not start cooling or heating

Safety first: Isolate power to both indoor and outdoor Camry units at the breaker before opening any covers.

• 1. Verify wiring connections: Remove the indoor unit front panel and outdoor electrical cover. Confirm that terminals L, N, and S (or 1, 2, 3 depending on model) are wired identically at both ends and that screws are tight.
• 2. Check for polarity errors: Ensure live (L) and neutral (N) are not swapped between indoor and outdoor units. Incorrect polarity can cause E1 communication errors.
• 3. Inspect communication cable: Look for cuts, crushed insulation, rodent damage, or signs of overheating on the interconnecting cable. Replace the cable if any damage is found, using the same gauge and type specified by Camry.
• 4. Measure continuity: With power off, use a multimeter to check continuity of the communication core(s) from indoor to outdoor terminals. Any open circuit or short to earth must be corrected.
• 5. Power cycle both units: After correcting wiring, turn power back on and wait 5–10 minutes to see if E1 clears.

When to call a technician: If wiring and cable are confirmed good and E1 remains, the communication circuit on either the indoor or outdoor PCB is likely defective and the corresponding Camry control board should be replaced by a professional.