Dialysis machines · 2008 family

Fresenius Medical Care 2008T: troubleshooting and error codes

The ServiceForge knowledge base holds 33 documented symptoms for the Fresenius Medical Care 2008T, with 54 ranked causes, 65 diagnostic checks with test points and expected values, and 34 error codes. Each symptom below shows its causes and the first check; the rest is one connection away. Connect ServiceForge to your AI

Symptoms

Calibration: CPRE sensor stability

Monitor CPRE (conductivity/pressure reading) value stability on debug screen #5 over 1 minute to verify sensor performance

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise interference (unknown)
3. -12V power supply problems (unknown)

First check

Monitor CPRE value stability

Test point: CPRE on debug screen #5
Expected: Difference between highest and lowest values ≤ 8 units, ≤ 8

Calibration: TPRE sensor stability

Monitor TPRE (temperature/pressure reading) value stability on debug screen #5 over 1 minute to verify sensor performance

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise interference (unknown)
3. -12V power supply problems (unknown)

First check

Access debug mode

Test point: keyboard
Expected: Main display changes to indicate debug mode

2 more checks with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

CPOS sensor value variation exceeds tolerance

Debug screen #5 CPOS value fluctuates more than 8 units over 1-minute observation period

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise coupling into sensor (unknown)
3. -12V power supply problems (unknown)

First check

Observe CPOS value on debug screen #5 for 1 minute

Test point: Debug screen #5, CPOS parameter
Expected: Difference between highest and lowest ≤ 8

CPRE sensor variability out of specification

Debug screen #5 shows CPRE value fluctuating; difference between highest and lowest readings exceeds 8 units over 1 minute observation

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise interference (unknown)
3. -12V power supply problems (unknown)

First check

Measure CPRE value stability

Test point: Debug screen #5 CPRE display
Expected: Difference between highest and lowest ≤ 8 units, ≤ 8

Power failure battery alarm does not sound or Battery Test fails patient safety

Audible alarm does not activate when mains power removed, or internal battery test fails during alarm test

Ranked causes

1. 9-volt battery depleted or missing (common)
2. Power Logic Board IC9 failure (rare)
3. Power Logic Board failure due to swollen battery (occasional)

First check

Remove 9-volt battery and perform Alarm Test

Test point: Battery Test function
Expected: Battery Test fails with battery removed

2 more checks with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

TPOS sensor value variation exceeds tolerance

Debug screen #5 TPOS value fluctuates more than 2 units over 1-minute observation period

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise coupling into sensor (unknown)
3. -12V power supply problems (unknown)

First check

Observe TPOS value on debug screen #5 for 1 minute

Test point: Debug screen #5, TPOS parameter
Expected: Difference between highest and lowest ≤ 2

TPRE sensor variability out of specification

Debug screen #5 shows TPRE value fluctuating; difference between highest and lowest readings exceeds 2 units over 1 minute observation

Ranked causes

1. Sensor board malfunction (unknown)
2. Motor noise interference (unknown)
3. -12V power supply problems (unknown)

First check

Access debug mode

Test point: Keyboard CTRL + [▲] and [▼] keys
Expected: Main display changes to indicate debug mode

2 more checks with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

Alarm Test fails to trigger expected system response patient safety

Test board stimulus applied but functional board and blood systems do not respond as expected; alarms not triggered or systems not shut down

Ranked causes

1. Test board malfunction or communication failure with Functional board (common)
2. Functional board detector or response circuit failure (occasional)

First check

Verify Alarm Test prerequisites before start

Test point: Machine state
Expected: alarm free, TX Clock stopped, dialysate lines in shunt box, no blood sensed

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Arterial Pressure Hard Limit alarm not triggered patient safety

Test board stimulus to arterial pressure transducer does not cause Functional board to detect over/under limit condition and shut blood pump

Ranked causes

1. Arterial pressure transducer offset adjustment circuit malfunction (common)
2. Functional board ADC conversion failure or threshold comparison error (occasional)

First check

Art High Hard: Measure transducer offset voltage with DAC detuning at 0V

Test point: Arterial pressure transducer output (Vout)
Expected: considerably above 5V (>350 mmHg equivalent)
Tools: DMM

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood pressure module pressure calibration error

Display pressure and external pressure meter reading differ by more than 3 mmHg

Ranked causes

1. Calibration drift or sensor error in module (unknown)
2. Over-pressure relief not functioning (unknown)

First check

Compare display pressure to calibrated external meter

Test point: M400/TM-2910/TM-2915/TM-2917 use external pressure meter; M2000/M2600/M3600/SunTech use T-fitting setup
Expected: Display and meter pressures agree within 3 mmHg at stabilization

1 more check with pass and fail actions, 3 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Diasafe Test fails or does not meet pressure rise requirement patient safety

Diasafe valve test does not achieve 60 mmHg pressure rise at 2000ml/min UF rate or final pressure remains below 300 mmHg

Ranked causes

1. Diasafe valve V28 or check valves stuck or leaking (common)
2. UF pump membrane or rotor worn; flow delivery degraded (occasional)

First check

Record baseline dialysate pressure at 4000ml/min UF rate after 100 strokes

Test point: Dialysate pressure reading (DIAL-PRESSURE channel 4)
Expected: stable reading after 100 strokes

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pressure Test fails during stabilization phase patient safety

Pressure reading during 20-30 second stabilization period falls outside expected range, test terminates as failed

Ranked causes

1. Pressure transducer drift or calibration error (common)
2. Air in pressure lines during test (occasional)

First check

Measure positive pressure (Get Pos TMP) at start of test

Test point: Dialysate pressure sensor
Expected: at least +350 mmHg

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Pressure Test fails negative pressure phase patient safety

Negative pressure reading during test falls outside range -250 to -450 mmHg or varies more than 21 mmHg

Ranked causes

1. Dialysate pump or UF pump mechanical wear or failure (common)
2. Pressure transducer malfunction or calibration drift (occasional)

First check

Achieve negative pressure (Get Neg TMP) before flow test

Test point: Dialysate pressure sensor
Expected: at least -270 mmHg

2 more checks with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Relay contact test LEDs do not light caution

D6 and/or D19 LED on LP450 board fail to light when level down switch is pressed

Ranked causes

1. Relay contacts are bad or LP450 board malfunction (unknown)
2. Relay contacts fail when blood alarm active (unknown)

First check

Press level down switch and verify LED illumination

Test point: D6 and D19 LEDs on LP450 board
Expected: both LEDs D6 and D19 light

1 more check with pass and fail actions, 2 corrective actions, and part numbers are in ServiceForge. Connect ServiceForge to your AI

5V supply voltage out of tolerance high voltage

Internal 5-volt supply measured on debug screen #4 not within 0.2V specification

Ranked causes

1. 12-volt supply out of tolerance (common)

First check

Access debug screen #4

Test point: Machine display
Expected: Debug screen #4 displayed

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Arterial pressure transducer calibration out of specification patient safety

Arterial Pressure bargraph does not match external pressure meter at 0 and 200mmHg calibration points

Ranked causes

1. Pressure transducer contamination or malfunction (occasional)

First check

Inspect internal pressure transducer protector

Test point: Arterial transducer PART port protector
Expected: No contamination visible

5 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood dimness detector voltage out of range patient safety

Blood dimness level measured on debug screen #4 outside 5.0±1.0V specification

Ranked causes

1. Contamination in glass detector tube (occasional)

First check

Access debug screen #4

Test point: Machine display
Expected: Debug screen #4 displayed

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood leak detector voltage out of range patient safety

Blood leak level measured on debug screen #4 outside 4.5-5.2V specification

Ranked causes

1. Contamination in glass detector tube (occasional)

First check

Access debug screen #4

Test point: Machine display
Expected: Debug screen #4 displayed

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood pressure module air leakage exceeds limit

Cuff pressure drops more than specification during air leakage test

Ranked causes

1. Tubing leak, connection leak, or internal valve leakage (unknown)

First check

Measure air leakage rate

Test point: Module-specific Dummy Cuff port (M400/M2000/M2600: 220cc; M3600: 220cc; TM-2910/TM-2915/TM-2917: 700cc; SunTech: 700cc)
Expected: M400/M2000/M2600: ≤15 mmHg; M3600: ≤12 mmHg; TM-2910/TM-2915/TM-2917: ≤30 mmHg; SunTech: ≤22 mmHg

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood pressure module deflation speed out of range

Module deflates at rates outside specification at various pressure points during deflation test

Ranked causes

1. Degraded or faulty deflation control valve (unknown)

First check

Measure deflation rate at 240 mmHg

Test point: Dummy Cuff 220cc port
Expected: M400: 4.3-6.2 mmHg/sec; M2000/M2600: 4.4-6.7 mmHg/sec; M3600: 3.8-6.6 mmHg/sec; TM-2910/TM-2915/TM-2917: 3.5-7.5 mmHg/sec

3 more checks with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood pressure module inflation speed out of range

Module takes longer than specified to pressurize dummy cuff to 250 mmHg during inflation speed test

Ranked causes

1. Module type mismatch or degraded inflation performance (unknown)

First check

Measure inflation time to 250 mmHg

Test point: Dummy Cuff 700cc port
Expected: M400: ≤7.3 seconds; M2000/M2600/M3600: ≤10.0 seconds; TM-2910/TM-2915/TM-2917: ≤10.0 seconds; SunTech: ≤11.0 seconds

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Blood pump rotor occlusion pressure out of range patient safety

Peak pressure measured at pump outlet during occlusion test falls outside 25-35 psi range

Ranked causes

1. Blood pump rotor springs worn or damaged (common)

First check

Measure peak pressure at blood pump outlet during occlusion

Test point: pressure gauge between pump output and clamp
Expected: between 25 and 35psi, 25-35 psi
Tools: pressure gauge

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Deaeration pressure out of specification caution

Deaeration pump inlet pressure not within acceptable range when dialysate flow is ON

Ranked causes

1. Deaeration pump adjustment needed (unknown)

First check

Install pressure gauge on deaeration pump inlet

Test point: Inlet (suction) side of deaeration pump
Expected: Gauge installed with T-fitting

3 more checks with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

Dialysate line safety interlock malfunction patient safety

Safety switches for dialysate lines and bypass shunt cover do not function properly

Ranked causes

1. Dialysate line safety interlock switches defective or misaligned (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Dialysate tubing damaged or cracked caution

Visible damage, cracks, or deterioration on dialysate lines at machine connections

Ranked causes

1. Aging, UV exposure, or mechanical damage to tubing (unknown)

First check

Visually inspect upper dialysate line for damage

Test point: Upper dialysate line connection point at back of machine
Expected: No cracks, tears, discoloration, or visible deterioration

1 more check with pass and fail actions, 1 corrective action, and part numbers are in ServiceForge. Connect ServiceForge to your AI

Flow relief pressure out of specification caution

Flow pump outlet pressure not within specified range during service mode test

Ranked causes

1. Flow pump relief valve adjustment needed (unknown)

First check

Enter Service Mode and access Calibrate Hydraulics screen

Test point: Machine main display
Expected: Calibrate Hydraulics screen displayed

2 more checks with pass and fail actions are in ServiceForge. Connect ServiceForge to your AI

Heat disinfect mode dialysate temperature below specification patient safety

Dialysate temperature fails to reach 80-90°C during heat disinfect mode

Ranked causes

1. Heater malfunction or insufficient heating (common)

First check

Monitor dialysate temperature during heat disinfect mode

Test point: external temperature meter on dialysate lines
Expected: between 80°C and 90°C, 80-90°C
Tools: external temperature meter capable of reading at least 85°C

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Level detector alarm channel LEDs do not light in sequence patient safety

Channel 1 and/or Channel 2 LEDs on level detector circuit board do not light when venous chamber is removed

Ranked causes

1. Level detector circuit board malfunction (unknown)

First check

Watch Channel 1 and Channel 2 LEDs when venous chamber is removed

Test point: Channel 1 and Channel 2 LEDs on circuit board
Expected: Channel 1 LED lights first followed quickly by Channel 2

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Occlusion clamp does not fully seal venous line patient safety

Air escapes from venous line when pressure applied, indicating incomplete occlusion

Ranked causes

1. Occlusion clamp worn or damaged (common)

First check

Apply pressure to venous line and observe for air leakage

Test point: end of venous line in water container
Expected: no air escapes from the venous line psi
Tools: syringe, pressure gauge

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

OLC test resistor plug replacement

Replace test connectors on distribution board and install calibration resistor plugs for OLC testing

Ranked causes

1. OLC sensor testing required (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Patient exposure to improper dialyzing fluid patient safety

Patient exposed to dialyzing fluid with incorrect temperature or conductivity during treatment

Ranked causes

1. Dialyzer valves V24, V25, V26 fail to bypass dialyzer during alarm condition (unknown)

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Rinse flow rate below minimum caution

Less than 310 ml collected in 30 seconds during rinse mode flow test

Ranked causes

1. Rinse circuit blockage or pump flow reduction (common)

First check

Measure rinse drain flow volume in 30 seconds

Test point: drain line collected in graduated cylinder
Expected: minimum of 310ml in 30 seconds
Tools: 1000ml graduated cylinder, timer

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Ultrafiltration pump does not deliver output

Green pump light is on but pump produces no flow output

Ranked causes

1. Check valve installed backwards (occasional)

First check

Verify check valve orientation in UF pump

Test point: Check valve inlet/outlet markings on valve body
Expected: Flow direction arrow pointing toward outlet; valve installed with correct polarity

1 corrective action and part numbers are in ServiceForge. Connect ServiceForge to your AI

Error codes

Code	Meaning	Trigger	Severity
`A.11`	Pump is not reaching speed.	Blood pump fails to achieve target speed	warning
`A.13`	Pump rotor is turning in the wrong direction.	Blood pump rotor rotates in reverse or incorrect direction	error
`A.16`	Key stuck or held in too long.	User holds a key down or key is stuck mechanically	warning
`A.20`	Set speed read-back analog voltage at X348/14 is out of limits.	Set speed feedback voltage exceeds allowable range	error
`A.21`	Actual speed read-back analog voltage at X348/10 is out of limits.	Actual speed feedback voltage exceeds allowable range	error
`A.22`	Arterial pressure read-back analog voltage at X348/7 is out of limits.	Arterial pressure feedback voltage exceeds allowable range	error
`A.24`	Optical sensor frequency (tach) not in range.	Tachometer signal frequency outside expected range	warning
`A.25`	Pressure increases too quickly when Level Up key is pressed.	Pressure rises at excessive rate during level adjustment	warning
`A.26`	Pressure was adjusted too much in calibration mode.	Pressure adjustment exceeds safe limits during calibration	critical
`A.27`	Timeout when receiving Intel-Hex-line or overflowed receive buffer.	Communication timeout or buffer overflow during firmware update	error
`A.28`	Error in received Intel-Hex-line.	Corrupted or invalid data received during firmware transfer	error
`A.29`	Pump rotor turning when it should not be (first revolution).	Rotor rotates during initialization or standby	error
`E.01`	EPROM CRC error.	EPROM checksum validation fails at startup	critical
`E.02`	Flash ROM CRC error.	Flash ROM checksum validation fails	critical
`E.03`	RAM check error.	RAM self-test fails during initialization	critical
`E.04`	Reference Voltage error.	Reference voltage circuit failure detected	critical
`E.05`	Serial EEPROM error.	EEPROM communication or checksum failure	critical
`E.06`	Watchdog timeout.	CPU watchdog timer expires indicating system hang	critical
`E.07`	+12 volts is outside the allowable range of 10.8 to 13.2 volts.	+12V supply voltage falls outside specified limits	critical
`E.08`	+24 volts is outside the allowable range of 22.8 to 28.0 volts.	+24V supply voltage falls outside specified limits	critical
`E.09`	-12 volts is outside the allowable range of -9.6 to -13.2 volts.	-12V supply voltage falls outside specified limits	critical
`E.10`	+5 volts is outside the allowable range of 4.75 to 5.25 volts.	+5V supply voltage falls outside specified limits	critical
`E.14`	50 ms time period exceeded.	Software task execution exceeds 50 millisecond deadline	error
`E.15`	Software task was not completed correctly.	Task completion check fails during execution	error
`E.23`	Pump rotor turning when it should not be (second revolution).	Rotor continues rotating during initialization standby phase	error
`E.97`	Error copying data into Flash ROM.	Flash write operation fails during firmware update	critical
`E.98`	Error erasing Flash ROM.	Flash erase operation fails during firmware update	critical
`E.99`	Transmit error during Flash update.	Communication error occurs while sending firmware data	critical
`Fill Program Alarm`	Filling program runs for more than 60 seconds with blood sensed	Filling program continues beyond 60 seconds while blood is detected	critical
`Flow Error`	Chamber full switch does not switch balance chamber	CFS (chamber full switch) does not switch the balance chamber for 10 seconds	error
`Flow Inlet Error`	Float switch does not detect low water level after balance chamber cycle	Float switch does not detect low level within 2.5 seconds after balance chamber cycles	error
`High Flow Error`	Balance chamber cycles too rapidly	CFS (chamber full switch) switches the balance chamber faster than 1.8 seconds	error
`No Water`	Water level not detected after float switch opens valve 41	Float switch opens valve 41 but water level not up within approximately 6 seconds	error
`RED LED`	Pump door is open longer than preset time (default 30 seconds).	Door remains open beyond time limit set by dip-switch 4 on LP955	warning

Likely causes and actions for each code are in ServiceForge. Connect ServiceForge to your AI

Community

0 fixes logged by technicians through their AI, with outcomes, for this model.

ServiceForge knowledge base record. Field-unverified unless technicians confirmed it. A teaching summary of the record, not a service manual. Export 2026-10-14.