Indoor unit stops shortly after starting, display shows E1 and outdoor unit does not run.

Safety first: Isolate power to both indoor and outdoor units at the breaker. Verify with a non-contact voltage tester before touching terminals.

Steps:

• Check terminal block wiring: Remove the front cover of the indoor unit and the service cover of the outdoor unit. Confirm that terminals 1–2–3 (or L–N–S depending on model) are wired identically at both ends and that screws are tight.
• Inspect cable: Follow the interconnecting cable between indoor and outdoor units. Look for crushed insulation, rodent damage, or splices. Repair or replace damaged cable with the same gauge and type recommended by Blaupunkt.
• Verify polarity: Ensure live (L), neutral (N), and signal (S or 3) are not swapped. Incorrect polarity is a common cause of E1 on Blaupunkt split systems.
• Test continuity: With power off, use a multimeter to check continuity of each conductor between indoor and outdoor terminals. Resistance should be near zero ohms.
• Board diagnosis: If wiring is correct and E1 persists, either the indoor or outdoor main PCB communication circuit may be defective. At this point, replacement of the suspect PCB (starting with the indoor board) is usually required.