Bosch Mini Split E5 Error Code

Updated 2026-08-29 · review status: manual-verified Last verified: 2026-08-29

Quick answer

E5 means an indoor coil temperature sensor error on Bosch Climate 5000 Gen 2 / legacy single-zone systems - the evaporator (T2) thermistor is open, shorted, or reading outside its allowed window, so the control stops the system. On multi-zone Bosch outdoor boards E5 instead means over-voltage or under-voltage protection; confirm which display you are reading.

Severity: medium · DIY difficulty: simple

Safety

Only a power-cycle reset and visual checks you can do without removing any panel. Do not open covers, unplug or test sensors, spray anything into the unit, connect gauges, or replace PCBs - high-voltage inverter components and refrigerant work are technician-only.

What E5 means

E5 means an indoor coil temperature sensor error on Bosch Climate 5000 Gen 2 / legacy single-zone systems - the evaporator (T2) thermistor is open, shorted, or reading outside its allowed window, so the control stops the system. On multi-zone Bosch outdoor boards E5 instead means over-voltage or under-voltage protection; confirm which display you are reading.

Code meaning varies by series

  • Bosch Climate 5000 Gen 2 / legacy single-zone: Indoor coil (evaporator, T2) temperature sensor open circuit or short circuit (indoor LED: 5 off) - Gen 3 equivalent EH 61
  • Bosch multi-zone outdoor board: Over-voltage or under-voltage protection (indoor shows P1)

Causes, ranked

  1. 1. Transient sensor reading after a power disturbance occasional diy-ok

    Check: Turn the system off with the remote, power cycle once at the breaker for 2-3 minutes, restart.

    Fix: One reset only. If E5 returns, stop resetting - the sensor circuit needs service.

  2. 2. Evaporator T2 thermistor open circuit or short circuit (broken wire, drifted element, or connector corrosion) occasional pro-only

    Check: Technician only: sensor resistance measured against the Bosch resistance-temperature chart.

    Fix: Technician: replace the evaporator coil thermistor with the correct Bosch part.

  3. 3. Loose, damaged, or corroded sensor connector or harness occasional pro-only

    Check: Technician only: connector seating and harness continuity behind the indoor panel.

    Fix: Technician: reseat/repair the connector and harness.

  4. 4. Indoor PCB input misreading the sensor circuit occasional pro-only

    Check: Technician only: verify PCB input after the sensor tests in spec.

    Fix: Technician: replace the indoor main PCB.

  5. 5. Multi-zone reading: supply voltage out of range (over/under-voltage protection) occasional diy-ok

    Check: Check the breaker is fully on and sized correctly; note whether other large equipment shares the circuit.

    Fix: Persistent voltage issues -> electrician or technician; do not keep restarting.

Related codes

bosch/e4 · bosch/e1 · bosch/ec51

Commonly searched as: "bosch e5" · "bosch error code e5" · "bosch air conditioner e5"

Sources

  • Heat Pump Answers - Bosch Mini Split Error Codes (Gen 2 table: E5 indoor coil T2 sensor) — verified 2026-08-29
  • SplitAtlas Bosch E5 page (indoor coil temperature sensor error, Climate 5000 A/B) — verified 2026-08-29
  • HVAC Laboratory - Bosch error code guide (E5 in sensor-fault group E2/E3/E5/E6) — verified 2026-08-29