Espar (Eberspächer) Furnace: “012”

warning RV furnace fault codes

Safety Treat any overheat warning seriously and restore full airflow before reuse. Do not bypass temperature sensors. If exhaust odour ever enters the living space, stop the heater and ventilate, due to carbon monoxide risk.

What it means

Overheating detected by software: the outlet (heat-exchanger) temperature exceeded the software-defined limit, even though the hardware overheat sensor has not yet tripped. The control unit reacts to protect the heat exchanger.

Most likely causes

Reduced air throughput from partially blocked intake or outlet ducting most likely
Outlet/overheat temperature sensor reading high or out of spec common
Cable fault between sensor and control unit less common

Safe checks you can do yourself

Check warm-air intake and outlet for any restriction and clear it.
Confirm ducting is not kinked or excessively restricted.
Let the unit cool and restart, watching whether the fault returns.

How to reset / clear 012

Let the heater cool fully.
Switch off and back on at the controller.
If it persists, the outlet sensor should be tested by an installer.

When to call a technician

If the fault recurs after airflow is confirmed clear, or if a faulty outlet sensor is suspected.

Applies to

Airtronic D2 · Airtronic D4 · Airtronic D4S · Airtronic B4

FAQ

What does Espar (Eberspächer) Furnace code "012" mean?

How do I reset Espar (Eberspächer) Furnace 012?

Let the heater cool fully. Switch off and back on at the controller. If it persists, the outlet sensor should be tested by an installer.

What is the most common cause of 012 on a Espar (Eberspächer) Furnace?

The most likely cause is reduced air throughput from partially blocked intake or outlet ducting.

Related · Espar (Eberspächer) furnace

017
Overheat shutdown. The temperature measured at the overheat … 019
Glow plug (glow pin) energy too low: the glow plug is not de… 020 / 021 / 022
Glow plug electrical fault: 020 = open circuit / interruptio… 047 / 048
Metering (fuel dosing) pump fault: 047 = short circuit / ove… 050
Operating lockout: too many unsuccessful start attempts. Aft… 052
Unsuccessful start (no flame established). The heater attemp…

Sources

Eberspacher Airtronic Fault Codes — Airtronic fault code list, code 012 (Le Tonkinois (independent Eberspacher reference))
Find and clear Espar Airtronic fault codes and Eberspacher Hydronic fault codes — Overheating detection, P000115 (012) (Heatso)

Note: Newer controllers report this as P000115. Distinct from hardware overheat (017).

● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.