MX-M260/M310/M260N/M310N  SELF DIAG AND TROUBLE CODE 7 - 8
H4 01 Content Sub heater lamp abnormally low 
temperature detection
Details The setup temperature (about 90°C) is not 
reached within the specified time (about 
17sec) from turning on the power. 
When the temperature of sub heater 
thermistor falls below 140°C in the standby 
mode or printing.
When the temperature of sub heater lamp 
thermistor falls below 50°C in the pre-heat 
mode.
Cause Sub heater lamp thermistor defect.
Sub heater lamp failure.
Sub thermostat failure.
Control PWB failure.
Check 
and 
remedy
Check the sub heater lamp blinking with 
SIM 5-2-2.
When the lamp blinks normally:
Check the thermistor and the harness.
Check the MCU PWB thermistor input 
circuit.
If lamp lights and stays lit:
Check the power circuit and the lamp 
control circuit on MCU PWB.
Clear the display of self-diagnostics with 
SIM 14.
20 Content Main heater lamp abnormally low 
temperature detection
Details The setup temperature (about –25°C: Sim 
43-1-1) is not reached within the specified 
time (about 32sec) from turning on the 
power.
A/D value of fusing main thermistor is not 
reached within the specified temperature. 
(specified temperature : SIM43-1 (600dpi)
–25°C )
Cause Main thermistor defect.
Main heater lamp failure.
Main thermostat failure.
Control PWB failure.
Check 
and 
remedy
Check the main heater lamp blinking with 
SIM 5-1.
When the lamp blinks normally:
Check the thermistor and the harness.
Check the MCU PWB thermistor input 
circuit.
If lamp lights and stays lit:
Check the power circuit and the lamp 
control circuit on MCU PWB.
Clear the display of self-diagnostics with 
SIM 14.
Check that there is no foreign material in 
the contact section between the thermistor 
and the heat roller. 
Trouble 
code
Details of trouble
Main 
code
Sub 
code
H4 21 Content Sub heater lamp abnormally low 
temperature detection
Details The setup temperature (about –25°C: Sim 
43-1-1) is not reached within the specified 
time (about 32sec) from turning on the 
power. 
A/D value of fusing sub thermistor is not 
reached within the specified temperature 
(specified temperature : SIM43-1 (600dpi)
–25°C )
Cause Sub thermistor defect.
Sub heater lamp failure.
Sub thermostat failure.
Control PWB failure.
Check 
and 
remedy
Check the sub heater lamp blinking with 
SIM 5-2-2.
When the lamp blinks normally:
Check the thermistor and the harness.
Check the MCU PWB thermistor input 
circuit.
If lamp lights and stays lit:
Check the power circuit and the lamp 
control circuit on MCU PWB.
Clear the display of self-diagnostics with 
SIM 14.
Check that there is no foreign material in 
the contact section between the thermistor 
and the heat roller. 
H5 01 Content 10 times of continuous detection of the 
lower paper exit sensor (POD1) lead edge 
jam or the upper paper exit sensor (POD2) 
lead edge jam or the duplex sensor 
(PPD2) rear edge jam
Details After supplying the power, one of the 
above jams occurs 10 times continuously 
in printing
Counting is started on supplying the 
power. When any one of the above jams 
occurs, one count is made. When paper 
entry to the POD1 or POD2 is detected, 
the counter is cleared.
Cause A paper jam (paper rounding, etc.) near 
the duplex sensor (PPD2) on the fusing 
unit is not canceled completely.
POD1, POD2, PPD2 sensor breakdown or 
harness connection trouble
Fusing unit installation failure
Check 
and 
remedy
Check for jam paper in the fusing section. 
(paper winding, etc.)
Check fusing unit installation.
Check the POD1, POD2 or PPD2 sensor.
Clear the trouble with SIM 14.
Trouble 
code
Details of trouble
Main 
code
Sub 
code