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Eberspacher Fault codes.

Fault codes are generated by modern Eberspacher heaters (eg D*LC, D*LCC, Airtronics and Hydronics), these have a blue/white wire for connection to diagnostic testing equipment like the 801 and some 701 controllers.
Models prior to these have no diagnostics.
DO NOT wipe the fault codes without permanently recording them, this information can contain valuable clues for anyone diagnosing problems.
Some serious faults lock out the heater for safety reasons, always clear those faults before resetting.
Description 'open circuit' means no electrical path exists, like a wire disconnected or broken.
Description 'short circuit' means an electrical path exists, like two uninsulated wires touching together.
Connector S1 is on the cable from the Airtronic. Connector B1 joins this to the wiring loom.
Early model Airtronic ECUs have a plastic cable covering, later generation ECUs have a tape covering and are said to be more reliable.
Use the fault codes as a starting point, look at our other pages for more help if required.
Be aware that where the code shows a component has failed the ECU is unable to identify if it is the component itself that has failed or the electronic circuitry inside the ECU between the main microprocessor brain and the wiring is damaged.
If you have any faulty parts except for glowpin screens or gaskets please donate them to us for science, we learn a lot from faulty parts.

This fault table is for Airtronic and Hydronic models but most fault codes apply to other models.
I found the Fault code table in the Eberspacher D2 manual has many errors, mostly probably due to translation into English, that mean some of the explanations in the manual are almost meaningless to general users.
I used the information from that manual but I corrected obvious errors plus added material from our own experience.
This table will be updated as other water heater pages are added.
Fault codes greater than 99 do not exist, if displayed look at the Weird faults section on the Faults page.








1  Eberspacher Airtronic Fault Codes         letonkinoisvarnish.uk

Code
Faulty description
Comments and remedial action.

Fault table corrected plus additional information by
www.letonkinoisvarnish.uk
DO NOT wipe the fault codes without permanently recording them, this information can be valuable for anyone diagnosing problems.
Some serious faults lock out the heater for safety reasons, clear before resetting.
000
No faults

004
Short circuit fresh air output
Check wiring on Connector B1 pin 16 for short circuit to earth. 
   If ok replace ECU
005
Short circuit car alarm output
Check wiring on Connector B1 pin 15 for short circuit to earth.
   If ok replace ECU
009
Cut off ADR

This can also be a spurious fault code.
a)ADR shutdown B1 pin 13 or 14.  ADR is only used for vehicles carrying hazardous materials.
b)Fault code 09 can also be generated after a heater is disconnected from power with the heater switch in the on position. A typical cause is disconnecting a plug after the heater has failed to start without turning off the switch on the controller.
It can sometimes be erased by a diagnostic unit. Sometimes the code will not clear and a known fault needs to be introduced i.e. pull the fuel pump wires off and start the heater 5 times, this will move the fault to the end of the fault code memory and then it will be over written as the heater can only hold 5 faults.
If that fails replace the ECU.
010
Overvoltage cut off
Voltage over 16 volts continuously for at least 20 seconds,
(32 volt for 24 volt heaters)
Check alternator regulator or disconnect battery charger.
Possibly 12 volt heater connected to 24 volt battery but this could damage the ecu.
011
Undervoltage cut off
(Low voltage at heater)
Voltage under 10.5 volts continuously for at least 20 seconds
(21 volts for 24 volt heaters)
IMPORTANT measure at the heater, not at the battery terminals where the voltage can be a lot higher. Usually occurs during starting when glowpin is on.
Extremely common fault, usually due to a discharged battery but many other reasons described on our Low Voltage Faults page.
The measurement method described in the Eberspacher Airtronic fault code list is almost useless, the heater must be connected and switched on so drawing current.
012
Overheating at overheat sensor
(Software threshold value)
Temperature of the overheating sensor too high.
Check heating air path for crushed pipes or blockages, air outlets closed or blocked.
    Often caused by accidentally puting objects against heating outlets.
Check if air pipes are too long or have too many bends. (Just replacing a straight outlet hood with right angle version can often put the piping outside specification.)
Check pumped fuel volume.
Check Overheat sensor.
Check blower fan as fault code 33.
The heater can be reset from fault codes 012 and 013 by switching off and back on.
Overheating is a serious safety issue and can damage the ECU so find and eliminate the cause before resetting.
More info on our Faults Main page, mainly in the Faults when running section.
013
Overheating at flame sensor
(Software threshold value)
Temperature of the flame sensor too high.
Check as fault code 012. Check Flame sensor instead of overheat sensor.
014
Temperature difference between flame and overheat sensors too large
Temperature difference between flame and overheat sensors too large.
Check as fault code 012.
Check both Flame sensor and Overheat sensor.
015
Overheating lock out.
This code displayed when the heater is switched on after fault code 017 was displayed.
(I have no idea why this fault code is needed, code 017 covers the problem!
   On Hydronic water heaters the code is for 10 overheats in succession).
More info in fault code 017.
017
Overheating lock out.
(Hardware limit value)
The temperature exceeded the maximum the overheat sensor can measure.
The ECU is locked for safety reasons.
The ECU failed to recognise overheating fault code 012 or 013.
My explanation on why 017 occurs is on the Faults Main page.
Heat may have damaged the ECU, if not it can be unlocked using appropriate equipment.
IMPORTANT  Identify and clear the cause of overheating before trying to reset.  This lockout is for a very serious safety problem.
More info on our Faults Main page.
019*
Ignition energy too low
*New generation ECUs only.
The glowpin heats the burner during starting so the fuel can ignite. The flame sensor measured the temperature which is not high enough to ignite the fuel.
Check glowpin. Check vent hole is clear, Check exhaust and combustion air path.
Check pumped fuel supply volume. Check flame sensor.
If all ok replace ECU
020
Glowpin interruption
(Glowpin open circuit)
Check glowpin connector is fully pushed into ECU, plug has thick brown and white wires.
Check for broken wires.
Check glowpin resistance, 12 volt 0.42 to 0.7 ohms,  24 volt 1.2 to 2.5 ohm.
Measurement details and photos on Faults Main page and Airtronic Servicing page 2.
If all ok replace ECU
021
Glowpin short circuit to earth
Check glowpin resistance as in code 020
Check wiring for damage, usually close to glowpin due to removal without a modified socket.
Check for water in connectors and heater.
If all ok replace ECU
022*
Glowpin short circuit to battery positive supply
*New generation ECUs only.
Check wiring for insulation damage.
Check for water in connectors and heater.
If ok replace ECU.
025*
Diagnostic cable short circuit to battery positive supply
*New generation ECUs only.
Check blue/white wire is not damaged or loose and touching the +12 volt supply.
Check for water in connectors and heater.
This fault might only be read after the fault has cleared as it would disable the diagnostics signal.
031
Blower (fan) motor interruption.
(Blower open circuit)

Check blower (fan) motor plug is fully pushed into ECU, plug has black and white wires.  Photos on Airtronic servicing page 2.
Check wiring for damage.
Check resistance of the motor is roughly 0.5 ohms.
Worn motor brushes can give intermittent connections that do not show up on this test. Faulty motor segments may only show up while slowly rotating the shaft by hand.
If ok replace ECU. Before doing so connect a short circuit across the ECU fan connector pins and restart. If fault code changes to 032 fault is not ECU, probably intermittent motor.
032
Blower (fan) motor short circuit to earth or drawing excessive current.
Check wiring to fan for insulation damage.
Check for water in connectors and heater.
Check motor is free to rotate and not catching on case or ECU.
Check bearings are not starting to seize.
Check resistance of the blower motor is roughly 0.5 ohms.
Do not try to dismantle blower without reading Airtronic servicing and Blower pages.
Eberspacher say test the motor with an 8 volt 20 amp supply, not 12 volts.
Few users will have a suitable 8 volt supply so a dealer may be needed to diagnose.
After 40 seconds if current is more than 6.5 amps motor is faulty, otherwise replace ECU.
033
Blower (fan) not rotating or rotating at wrong speed
Speed deviation greater than 10% from specified for more than 30 seconds.
Check blower is free to rotate and not catching on case or ECU.  Sometimes glowpin wires can cause ECU to be pushed slightly towards the fan.
Check blower motor plug is fully pushed into ECU, plug with black and white wires.
The detector for the magnet is inside the ECU so check ECU is fitted correctly.
Measure the Blower speed using a non contact rpm meter / tachometer, one cost under 7.30 including post from China April 2016.
D2  Power 4800 140 rpm, High 4000 120 rpm, Medium 2800 80 rpm, Low 2000 60 rpm
D4  Power 4400 130 rpm, High 3500 100 rpm, Medium 2600 80 rpm, Low 1600 50 rpm
D5  Speeds are not quoted in manual
D1LCC  Power  5000 rpm, High 4400 rpm,  Medium 3000 rpm    Low 3000 rpm
D3LCC  Power  4200 rpm, High 4200 rpm,  Medium 2200?rpm   Low 3000 rpm    
If RPM is too high, check if magnet in impeller is mounted properly, photo Airtronic service page 2. The detector for the magnet is inside the ECU.
If RPM is too low, check air path for restrictions or blockage.
Check wiring for breaks, loose connections, faulty insulation.
Check as code 032.
Erratic blower speed can be caused by ECU earthing, see Faults page Weird faults section.
Blower brushes or bearings worn, replace blower.
Do not try to dismantle blower without reading Airtronic servicing and Blower pages.
If ok replace ECU.
034*
Blower (fan) motor short circuit to +12 volts
*New generation ECUs only.
Check for water in heater.
Manual says check wires for damage but unlikely to be cause in Airtronics as no +12v close.
If ok replace ECU.
047
Fuel metering pump short circuit to earth or overload current
Disconnect the wires on the pump connector, if fault code 048 is displayed pump is faulty.
(If the pump has to be replaced please donate the faulty one to us for science.)
If code 47 remains displayed also disconnect the main loom connector B1 and then check the wiring to the pump with a test meter for a short circuit. Most likely cause is mechanical damage to the insulation where cables are clipped in position or uninsulated connectors on older Eberspacher pump types touching the chassis.
Check for water in connectors and heater.
If ok replace ECU.
048
Fuel metering pump interruption
(Fuel pump open circuit)
Pump connector not fully pushed home or making a bad connection.
Common after disconnecting pump. Airtronic pumps use a locking spring, press it in whilst inserting connector, push fully home.
Disconnect the wires on the pump connector and measure the resistance of the pump.
The resistance of an Eberspacher D1LCC, D2, D4 or D5 pump should measure 10 0.5 ohms (24v 36 1.8 ohms). If not ok check connections for corrosion, replace pump, see code 047.
If ok reconnect the pump and disconnect the main Eberspacher loom connector B1.
Measure resistance across the connector pins 5 and 10 going to the pump.
If not ok wiring to pump is faulty, if ok check connectors S1 B1 for corrosion, replace ECU.
If no test meter is available the pump can be connected to a 12 volt battery, it should make a loud click each time it is connected. (Make sure the pump is disconnected before doing this test or you can destroy the ECU. Also take care not to accidentally short circuit the battery).
More info Fuel 2 page.
If ok replace ECU.
049*
Fuel metering pump short circuit to positive battery
*New generation ECUs only.
Check for pump wires loose or with damaged insulation.
Check for water in connectors and heater.
Check for incorrect wiring connections on new installations.
If ok replace ECU
050
Too many start attempts.
ECU locked out.
The ECU locks out after 255 consecutive start attempts (Airtronic heaters).
The count is reset if any other fault occurs during this time so code 050 indicates serious problems.
It can be unlocked with appropriate equipment.
051
Flame detected during switch on
(time exceeded blowing cold)
Flame sensor resistance above 1274 ohms at switch on indicates the temperature is above 70 degrees C and the fan runs to cool it down.
If  temperature does not fall below 70 degrees within aprox 15 minutes heater is switched off.
Check flame sensor, if ok replace ECU.
052
Safety time exceeded.
Unit failed to start on both start attempt sequences.
No flame was detected during the two start attempt sequences, unit shut down after a cooling down cycle.
This is simply a standard failure to start fault indication.
The causes are detailed in Faults Main page.
053
Flame cutout in Power stage
The flame extinguished during the Power stage.
The causes are detailed in Faults Main page in the section "Eberspacher starts normally but stops whilst running, it may try to restart."
054
Flame cutout in High stage
The flame extinguished during the High stage. Causes same as fault 053
055
Flame cutout in Medium stage
The flame extinguished during the Medium stage. Causes same as fault 053.
056
Flame cutout in Low stage
The flame extinguished during the Low stage. Causes same as fault 053.
060
External temperature sensor interruption  (open circuit)
External temperature sensor disconnected while heater was running.
If still open circuit it will be ignored during starting and heater will use its internal sensor.
Disconnect connector B1 and measure resistance between B1 pins 6 and  12
If greater than 7175 ohms check grey and brown/white wires and extensions for breaks.
Check Sensor resistance, it should be between 1600 and 2100 ohms (0 to +30 degrees C)
If ok ECU is faulty but it probably can still be used with the internal sensor.
061
External temperature sensor
short circuit
Disconnect connector B1 and measure resistance between B1 pins 6 and  12
If less than 486 ohms check grey and brown/white wires + extensions to sensor for damage.
Disconnect & check sensor, it should be between 1600 and 2100 ohms (0 to +30 degrees C)
062
Temperature control interruption
(open circuit)
Heater received the switch on signal from the controller but could not read the controller temperature setting.
Check grey/red wire for a break or loose connection.
For a rheostat type controller only, disconnect S1 B1 and measure resistance between B1 pin 6 and pin 7, the control should adjust from 1750 to 2180 80 ohms.
If ok replace ECU, otherwise with B1 still disconnected measure across rheostat pins with grey/red and brown/white wires. If not ok replace controller.
For more modern types of controller follow instructions on Faults Main page in section "Stage 2 Pre start failure".
063
Temperature control short circuit
Fault recognised only if it occurs in heating mode.
If heater switched on with this fault ventilation mode is selected, (no fault code).
Detailed instructions on Faults Main page in section "Stage 2 Pre start failure".
(The methods quoted in the manual will not work for some diagnostic equipment which need the controller on/off switch, eg the 801 controller.)
Fault code indicates resistance value was less than 486 ohms.

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064
Flame sensor interruption
(open circuit)
Detailed instructions on Faults Main page in section "Stage 2 Pre start failure".
Fault code indicates resistance value was greater than 7175 ohms.
065
Flame sensor short circuit
Detailed instructions on Faults Main page in section "Stage 2 Pre start failure".
Fault code indicates resistance value was less than 486 ohms.
071
Overheat sensor interruption
(open circuit)
Detailed instructions on Faults Main page in section "Stage 2 Pre start failure".
Fault code indicates resistance value was greater than 223k ohms.
072
Overheat sensor short circuit
Detailed instructions on Faults Main page in section "Stage 2 Pre start failure".
Fault code indicates resistance value was less than 183 ohms.
Remove blue connector from ECU, if code 071 is displayed replace combi sensor.
If code 072 continues to be displayed replace ECU.
074
ECU defective
Overheating threshold not detected by ECU, replace ECU
090
ECU problem
Sometimes it can be reset with appropriate equipment, if not replace ECU
091
External interference voltage
ECU affected by interfering voltages from vehicles electrical system.
Possible causes poor battery or battery charger.
Leisure batteries, especially ones continuously float charged, can deteriorate with no other obvious signs unlike engine batteries which fail to start the engine so are quickly replaced.
Simple voltage checks may still show ok even if battery is bad.
092
ECU defective (Rom error)
Memory inside ECU failed, replace ECU
093*
ECU defective
*New generation ECUs only.
Replace ECU
094
ECU defective EEPROM error
Programmable memory failed, replace ECU
095*
ECU defective
*New generation ECUs only.
Replace ECU
096
Internal temperature sensor faulty
Use an external sensor. Full details on the Remote Sensor page.
If the installation must use an internal sensor wire up an external sensor, feed the wires back into the case and fix the external sensor close to the original internal sensor.
097
ECU defective
Replace ECU
098*
ECU defective
*New generation ECUs only.
Replace ECU
099*
Too many resets in sequence
*New generation ECUs only.
Voltage short term drops below 5 - 6 volts (for 12 volt) or 7 - 8 volts (for 24 volt).
Check +12 volt and earth (0 volts) from the battery for loose or corroded connections.
Check fuse and fuseholder, check battery terminals, check battery cables for damage.
Check battery condition. Leisure batteries, especially ones continuously float charged, can deteriorate with no other obvious signs unlike engine batteries which fail to start the engine so are quickly replaced. Simple voltage checks may still show ok even if battery is bad. 
Locate and clear cause before trying to reset, this fault may damage the ECU.


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Code
Faulty description
Comments and remedial action.

Fault table corrected plus additional information by
www.letonkinoisvarnish.uk
DO NOT wipe the fault codes without permanently recording them, this information can be valuable for anyone diagnosing problems.
Some serious faults lock out the heater for safety reasons, clear before resetting.
000
No faults

005
Warning
Burglar alarm short circuit
*Hydronic II only.
Not normally used, check wiring & connectors.
009
ADR shutdown
*Hydronic II models.   ADR is only used for vehicles carrying hazardous materials.
010
Overvoltage cut off
Voltage over 16 volts continuously for at least 20 seconds,
    32 volts for 24 volt heaters.
    *Hydronic II models 15 or 30 volts for 10 seconds.
Check alternator regulator or disconnect battery charger.
12 volt heater connected to 24 volt battery.
011
Undervoltage cut off
(Low voltage at heater)
Voltage under 10.5 volts for at least 20 seconds without interruption.
    21 volts for 24 volt heaters.    *Hydronic II models 10 , 20 volts.
IMPORTANT measure at the heater, not at the battery terminals where the voltage can be a lot higher. Usually occurs during starting when glowpin is on.
Extremely common fault, usually due to a discharged battery but many other reasons described on our Low Voltage Faults page.
The measurement method described in the Eberspacher Hydronic fault code list is almost useless, the heater must be connected and switched on so drawing current.
012
Overheating at overheat sensor
(Software threshold value)
Temperature of the overheating sensor greater than 125 deg C.
Heater can be restarted by switching off and on again.
This is a safety issue so do not keep restarting if it continues to occur.
Check all hoses for water leaks.
Check water circuit is properly vented, ie no air.
Check header tank water level.
Check valves, especially isolating valves, have not been shut off or turned down.
Check for blockages in water circuit.
Check water pump functions.
Check if installing thermostat and non return valve that position and direction is correct.
Measure resistance of overheat and temperature sensors.
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
    If value is a great deal larger replace that sensor.
014
Temperature difference between overheat and temperature sensors too large
Temperature difference between flame and overheat sensors greater than 25°C.
Prerequisite for this fault code is that Hydronic is operating and the water temperature at the overheating sensor has reached minimum 80°C.
Check as fault code 012.
015
Overheating lock out.
(Too many faults)
The ECU is locked for safety reasons.
Heater has overheated more than 10 times in succession.
IMPORTANT  Identify and clear the cause of overheating before trying to reset. This lockout is for a serious safety problem.
Investigate causes as fault code 12.
Unlock using appropriate diagnostic equipment.
017
Overheating lock out.
(Hardware limit value)
The temperature exceeded 130°C the maximum the overheat sensor can measure.
The ECU is locked for safety reasons.
The ECU failed to recognise overheating fault code 012.
My explanation on why 017 occurs is on the Faults Main page.
Heat may have damaged the ECU, if not it can be unlocked using appropriate equipment.
IMPORTANT  Identify and clear the cause of overheating before trying to reset. This lockout is for a serious safety problem.
Check as fault code 012.
More info on our Faults Main page.
019
Glowpin 1 Ignition energy too low
*Hydronic II only.
Energy input less than 2000 watts.
Check Glowpin
Check ECU
020
Glowpin interruption
(Glowpin open circuit)
Check for broken wires.
Check glowpin resistance, 0.42 to 0.7 ohms,    24v glowpin  1.2 to 1.9 ohms
    Measuring accurately is not required for fault code 020.
    For fault code 021 use accurate measurement technique shown on Faults Main page and Airtronic Servicing page 2.
Manual gives alternative method but few users will have a suitable high current 8v supply.
Eberspacher advise that connecting to a 12v battery might destroy the glowpin but so far our users report they had no problem while doing a short duration test on 12v. Make sure leads include a fuse when testing for 021 code. Caution, glowpin will glow red hot if working ok.
021
Glowpin drawing excessive current or short circuit downstream of earth.
Check wiring for damage.
Check for water leaking inside heater and on connectors.
Check glowpin resistance as in code 020.
022
Glowpin drawing excessive current or short circuit downstream of +
*Hydronic II only.
Check wiring for damage.
Check for water leaking inside heater and on connectors.
023
Glowpin 2 interruption
(Glowpin open circuit)
*Hydronic II with second glowpin only.
Check as code 020
024
Glowpin 2 drawing excessive current or short circuit downstream of ground
*Hydronic II with second glowpin only.
Check as code 021
025
Diagnostic line fault
Heater remains operational
*Hydronic II only.
This fault may prevent diagnostics equipment working as it uses the blue/white wire.
Check blue/white diagnostic wire for damage or short circuit.
026
Glowpin 2 drawing excessive current or short circuit downstream of +
*Hydronic II with second glowpin only.
Check as code 022
029
Glowpin 2 ignition energy too low
*Hydronic II with second glowpin only.
Energy input less than 2000 watts.
Check as code 019
030
Blower fan motor not rotating or rotating at wrong speed
* this code not used Hydronic II
Check fan is free to rotate and not catching on anything.
Check wiring for breaks, loose connections, faulty insulation.
Check combustion air path, both inlet and exhaust, are not obstructed.
Blower brushes or bearings worn.
If testing motor on a dc supply use 6 or 8v, not 12v.
(Measurement as described in D4WSC D5WSC manual is completely wrong)
031
Blower fan motor interruption.
(Open circuit)
Check wiring for breaks or loose connections.
Check resistance of fan motor.
    Resistance should be approx  0.5 ohms, accuracy not critical for this test
    Rotating shaft slowly by hand while checking may reveal faulty segments.
If testing fan use 6 or 8v dc supply, not 12v. 
032
Blower fan motor short circuit to earth or drawing excessive current.
Check wiring to blower for insulation damage.
Check for water leaking inside heater and on connectors.
Check motor is free to rotate and not catching on anything.
Check bearings are not starting to seize.
Check resistance of blower motor which should be approx 0.5 ohms
    Use accurate measurement technique shown on Faults Main page
    and Airtronic Servicing page 2.
Replace motor.
If testing blower use 6 or 8v dc supply, not 12v.
033
Blower fan motor rotating at wrong speed
*Hydronic II only.
Check as code 030
034
Blower fan motor short circuit downstream of + or -
*Hydronic II only.
Check wiring to blower for insulation damage and touching other wiring.
Check for water leaking inside heater and on connectors.
037
Water pump not working
*Hydronic II only.
Check water pump
    Apply 12v to water pump, connector B1 pins 12 & 13  (Power input max 4 amps)
038
Relay for operating vehicle fan
interruption (Open circuit)
This fault is not displayed by all heater types.
* this code not used Hydronic II
Check wiring to relay for breaks or loose connection.
Check relay
    Disconnect 8 pin connector, measure on the connector part not going to the ECU.
    Measure resistance between pins 2 and 3.
    Depending upon type of relay a good reading should typically be around 80 ohms.
    If greater than 1000 ohms check relay coil resistance or replace relay.
039
Relay for operating vehicle fan
short circuit, overload or short circuit to ground.
* this code not used Hydronic II
Check wiring to relay for insulation damage or broken connection touching.
Check for water leaking inside heater and on connectors.
Check relay
    Remove relay, if fault 038 displayed replace relay.
Alternative method
    Disconnect 8 pin connector, measure on the connector part not going to the ECU.
    Measure resistance between pins 2 and 3.
    Depending upon type of relay a good reading should typically be around 80 ohms.
    If lower than 20 ohms remove relay. Then if resistance becomes very high replace relay.
041
Water pump interruption
(Open circuit)
Check wiring to water pump for damage or breaks.
Check resistance of the water pump, rotate shaft by hand while checking.
    Disconnect 14 pin connector, measure on the connector part not going to the ECU.
    Measure resistance between pins 10 and 11.
    No resistance figure is quoted but probably about 0.5 ohms.
If trying pump on 12v battery without water keep test very short.
042
Water pump short circuit to earth or drawing excessive current.
Check wiring to water pump for damage to insulation.
Check for water leaking inside heater and on connectors.
Check if pump is running dry.
    Vent heater, check header tank water level.
Disconnect connection in water pump cable harness.
    If error code 041 is then shown replace water pump.
043
Water pump short circuit downstream of +
Check wiring to water pump for damage to insulation.
Check for water leaking inside heater and on connectors.
047
Fuel metering pump short circuit to earth or overload current
Disconnect the wires on the pump connector, if fault code 048 is displayed pump is faulty.
    (If the pump has to be replaced please donate the faulty one to us for science.)
    If code 47 remains displayed  check the wiring to the pump with a test meter for a short circuit. Most likely cause is mechanical damage to the insulation where cables are clipped in position or uninsulated connectors on older Eberspacher pump types touching the chassis.
Check for water leaking inside heater and on connectors.
048
Fuel metering pump interruption
(Open circuit)
Pump connector not fully pushed home or making a bad connection.
Disconnect the wires on the pump connector and measure the resistance of the pump.
    The resistance of the pump should measure 10 0.5 ohms (24v 36 1.8 ohms).
    If not ok check connections for corrosion, replace pump.
If pump is ok check wiring to pump.
    Measure resistance from connector.
If no test meter is available the pump can be pulsed with a 12 volt battery.
    Connect and disconnect from the battery, each time it should make a loud click. (Make sure the pump wiring is not connected before doing this test or you can destroy the ECU.
    Also take care not to accidentally short circuit the battery).
    More info Fuel 2 page.
049
Fuel metering pump short circuit downstream of +
Check wiring to fuel pump for damage to insulation.
Check for water leaking inside heater and on connectors.
050
Too many start attempts.
ECU locked out.
*Hydronic II - The ECU locks out after repeated start attempts without flame detection.
Hydronic - The ECU locks out after 10 consecutive start attempt failures.
Manual is not clear, I think a failed start with the second start attempt counts as one failure.
IMPORTANT  Identify and clear the cause before trying to reset.
This lockout is for your safety as each attempt leaves unburnt fuel.
It can be unlocked with appropriate equipment.
051
Flame detected during switch on
(time exceeded blowing cold)
Flame sensor resistance above 1274 ohms at switch on indicates the temperature is above 70 degrees C and the fan runs to cool it down.
If  temperature does not fall below 70 degrees within aprox 4 minutes heater is switched off.
Check flame sensor.
    Disconnect 14 pin connector, measure on the connector part not going to the ECU.
    Measure resistance between pins 1 and 2.
    If reading greater than 1274 ohms replace sensor.
052
Safety time exceeded.
Unit failed to start on both start attempt sequences.
No flame was detected during the two start attempt sequences, flame sensor value was below 80°C. Unit shut down after a cooling down cycle.
This is simply a standard failure to start fault indication.
Most heaters checked will have this code in memory, usually it can be ignored as you will already know when it failed to start, it switched off without generating any heat.
The causes are detailed in Faults Main page.
053
Flame cutout in highest power stage.
The flame extinguished during the boost / highest power stage.
Fault code is deleted if automatic restart is ok.
The causes are detailed in Faults Main page in the section "Eberspacher starts normally but stops whilst running, it may try to restart."
054
055
056
057
058
Flame cutout in    high power
medium or medium 1
medium 2
medium 3
low power
The flame extinguished while operating.
Power stage naming is different for some heaters.
Fault deletion and causes same as fault 053.

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059
*Hydronic II only
Too rapid rise in water temperature
Vent air from system.
Open heater slide valve
Check water flow rate.
Check temperature sensor.
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
060
Temperature sensor interruption  (open circuit)
Check sensor wiring for damage or breaks.
Check temperature sensor.
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
Alternatively place short circuit across sensor (or connector pins for some models).
    If heater then shows error code 061 check and replace sensor.
    If 060 still appears replace ECU.
061
Temperature sensor short circuit, overload or short circuit to ground.
Check wiring to temperature sensor for damage to insulation.
Check for water leaking inside heater and on connectors.
Check temperature sensor
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
    If resistance is much lower replace sensor.
064
Flame sensor interruption
(open circuit)
Check sensor wiring for damage or breaks.
Check Flame sensor
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
    If resistance is much higher replace sensor.
065
Flame sensor short circuit
Check sensor wiring for damage.
Check Flame sensor
    Resistance approx  0°C 33,000Ω,      20°C 12,450Ω,     50°C 3600Ω,      100°C 670Ω
    If resistance is much higher replace sensor.
071
Overheat sensor interruption
(open circuit)
Overheating sensor signals temperature value outside the measuring range.
Check Overheat sensor resistance as fault code 012
Check sensor wiring for breaks and damage
072
Overheat sensor short circuit
Overheating sensor signals temperature value outside the measuring range.
Check Overheat sensor resistance as fault code 012
Check sensor wiring for damage.
074
ECU defective
Overheating threshold detection hardware defective, ECU locked.
Replace ECU
090
External interference  voltage /
External reset
ECU reset by external interference voltage.
Check as code 099
091
Internal reset
ECU faulty
092
ROM error
ECU faulty
093
RAM error
At least one RAM cell is not working, ECU faulty
094
EEPROM error
Checksum error, ECU faulty
095
Invalid data record
Checksum error, ECU faulty
096
Internal temperature sensor faulty / ECU  too hot
Internal temperature sensor faulty / ECU  too hot, ECU faulty
097
Internal device errror
Internal device error, ECU faulty
098
Main relay is faulty
ECU faulty
099
Too many resets.
Heater locked
Voltage short term drops below 5 - 6 volts (for 12 volt) or 7 - 8 volts (for 24 volt).
Heater locked.  This fault may damage the ECU.
Check +12 volt and earth (0 volts) from the battery for loose or corroded connections.
Check fuse and fuseholder, check battery terminals, check battery cables for damage.
Check battery charger, especially Ctek chargers with too thin power output cables.
Check battery condition. Leisure batteries, especially ones continuously float charged, can deteriorate with no other obvious signs unlike engine batteries which fail to start the engine so are quickly replaced. Simple voltage checks may still show ok even if battery is bad.
Locate and clear cause before trying to reset, this fault may damage the ECU.


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