Fault Code Lookup

HVAC Sales Master
E4
Temperature sensor fault (T3/T4/T5/Th/T3L/Tf)
This code typically points to
  • Open or shorted sensors
  • Wrong sensor connections
  • Ambient beyond operating range

Next checks to confirm
  1. Ohm all suspect sensors
  2. Check wiring
  3. Verify operating conditions

Escalation
Multiple sensors to check — isolate specific sensor.
Reset behavior
Clears when sensor reads correctly.
Service Soon
Schedule repair
Need deeper detail?
Retrieve the subcode for this platform:
  1. Connect the IDS system in EasyAir App
  2. Use the contractor view to monitor heat pump health
  3. Review real-time alerts, fault codes, and checkpoint values
  4. For on-site work, use Bluetooth-enabled access to system data and historical fault codes
  5. Calculate superheat/subcool within the app for diagnostic verification
  6. Bluetooth access is retained on-site even without continued remote subscription
Tool required: Bosch EasyAir App
Source
Bosch IDS 2.0 service documentation