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Eberspacher fault finding 1.
Many if not most Eberspacher faults can be identified and solved by a reasonable DIYer, saving expensive dealer repairs.
Our pages are aimed at owners who do not have a diagnostic tool to help them identify the fault.
Much of the information here is readily available from the Eberspacher manuals and from other sources.
Although the pages are for D1LC Compact, D2 and D4 Airtronic models most sections apply to other models.
Before doing any tests ensure the battery is well charged and in good condition.
Also check all connections for corrosion.
The most common Eberspacher faults
The commonest faults are due to:-
1 Poor electrical connections, low voltage or no power
Poor electrical connections.
Many intermittent problems are caused by corroded or loose connections or switch contacts.
They are one of the major fault causes for older heaters as they have had more time to corrode.
Low Voltage is not just caused by the battery being uncharged.
Usual symptom - Eberspacher shuts off 20 to 40 seconds after switch on.
It is important to realise that it is the voltage at the heater that matters, not at the battery terminals.
Eber Low Voltage page deals with solving low voltage problems in far more detail than any other web source.
No power is covered on the Eber Faults 2 page, Stage 1 faults.
Usual symptom - Nothing happens when switched on, no controller light.
2 Eberspacher in need of a mechanical service.
Usual symptom - Heater starts with difficulty, often on second attempt and / or smokes whilst starting.
Annual Service
As a first step replace the glow pin screen, it should be replaced annually and can be done without removing the heater.
Older generation heaters D1L D3L D5L do not use a screen.
Also check the the glow pin chamber breather hole and the fuel filter.
Full service
Heaters should be serviced every 2000 hours or every 2 years for low usage heaters.
D1L D3L D5L heaters are probably better off being left alone until problems arise.
Service may need to be done more often for some fuel types.
Eber Service page shows DIY servicing details.
3 Fuel supply
Various symptoms - the most common being flame out shutdowns.
As a first step check you have sufficient fuel, then check the fuel filter if not already done.
Eber Fuel Problem page deals with checking the pump, fuel filter and many other fuel supply faults.
4 Air and exhaust pipes and silencer obstructed or partially blocked.
Usual symptom - Difficulty starting. Overheat shutdown - heater does not try to restart until switched off and on again.
Check air inlet and output ports and pipes for obstruction or crushing.
Check combustion air inlet and exhaust pipes for obstructions.
Check silencer, this can be blocked with carbon deposits even if exhaust pipe looks reasonably clear.
These are probably responsible for more than 8 out of 10 Eberspacher faults and do not require much expertise to solve.
Hence they can be a easy point to start troubleshooting before doing the more detailed fault investigations on the next page.
Even if you do not find the fault and have to go to an Eberspacher dealer you will have lost nothing except a little time and effort.
Faults Page 2 shows more detailed Eberspacher troubleshooting and fault diagnosis
Eberspacher D1LC lockouts.
According to Eberspacher only the D1LC and some early D1LC Compact heaters produced between 1990-1998 have the lock out after 5 unsuccessful physical start attempts (each attempt means two automatic starts to give the 10 starts before lock out).
If the heater starts during these attempts it cancels previous non start fault codes and five new attempts are now available.
However should the heater lock out after these five unsuccessful physical start attempts then you will need to get it unlocked.
It can also lock out after 3 successive overheat faults.
I don't know how common these lock outs are but most people will try several times to start the heater when they have a problem.
We have several reports from users who had no lockouts despite doing many start attempts so would have expected problems.
In fact we have not met a locked out heater which leads us to suspect it may not be as much a problem as expected.
A locked heater usually has to be unlocked by an Eberspacher dealer or someone with a diagnostics tool.
We have a diagnostic unit with reset facilities for this purpose.
It seems to be very poor engineering design by Eberspacher to not provide a simple way of resetting without special tools.
Eberspacher information has the following advice.
Note that the features below are determined by software in heater’s ECU and may be different in some revisions of heaters:
In the event that a heater is not locked out, but simply fails one of the startup tests the heater will not run in ‘Heat’ mode, but may however run in ‘Vent’ mode. If the Mini-controller or Digi – controller is not available, vent mode can be accessed by ‘jumping’ the grey/red wire to the brown/white wire, then ‘jumping’ the red wire to yellow wire (order is important). If blower starts up and runs, then ECU is not locked. Otherwise it may or may not be locked.
If heater is able to start in ventilation mode, but can not run in heating mode:
check fuel metering pump for open or short circuit;
check glow pin for open or short circuit;
check overheat sensor for open circuit;
If heater does not work in either heat and vent modes:
check flame sensor for open or short circuit;
check overheat sensor for short circuit;
Eberspacher Airtronic D2 lockouts.
The D2 will lock out after 255 identical faults. Any different fault before lockout occurs will reset the counter.
It can also lock out in 'Overheat with excessive temperature' fault conditions, details on next page.
Providing no other components are damaged the ECU can be reset with equipment like the diagnostic unit or an 801 controller.
Page 2 continues with more detailed Eberspacher troubleshooting and fault diagnosis.