Error Messages, Codes, and Procedures 3-29
Fuser Failure - U4-n Over Heat / Thermistor
The Fuser failed to reach temperature within the warm-up period. The control
thermistors has detected a temperature higher than the specified value, or one of the
thermistors has failed.
Applicable Error Codes
Fuser Failure - U4-2 Over Heat Temp
Fuser Failure - U4-3 FS1 Thermistor
Fuser Failure - U4-4 FS2 Thermistor
Fuser Failure - U4-5 Pressure Roller Thermistor
10
Check the Fuser connection.
Is P/J6 connected?
Go to Step 11. Connect P/J6.
11
Check continuity between the Fuser and
LVPS.
Is there continuity on each wire
between P/J600 <=> P/J6?
Go to Step 12. Repair the wiring.
12
Check for +5 V to the Fuser.
Is there +5 V between these pins?
P/J6-1 <=> P6-2
P/J6-1 <=> P6-3
P/J6-1 <=> P6-4
Replace the Fuser
(
page 8-76)
Replace the
LVPS
(
page 8-92).
13
Check the LVPS and the Engine Logic
Board connection.
Are P/J401 and P/J525 connected?
Replace the
Engine Logic
Board
(
page 8-89).
Connect P/J401
and P/J525.
Fuser Thermistor Troubleshooting Reference
Applicable Parts References
â– Fuser
â– LVPS
â– Print Engine P/J Fuser and Exit 1 (page 10-8)
■“Print Engine Fuser Wiring (page 10-22)
â– PL6.1 Fuser and Exit 1 Unit (page 9-34)
â– PL8.1 Print Engine Electrical (page 9-40)
Fuser On Time Troubleshooting Procedure (Continued)
Step Actions and Questions Yes No