I had an errow E000003-0004 How do i fix that fault please Image runner c5045i advance

You need to clear that error from service mode first if problem persist replace the fixing unit

First you need to clear that error from service mode

error code please ?

Cyan Developer Fault

https://www.coronatechnical.com/2019/04/clear-error-e00027-for-canon.html

https://baitalahbarcomputers.blogspot.com/2021/06/canon-error-e000027-0300.html

https://www.google.com/search?q=Cannon+Image+Runner+Advance+C5045+error+code+E000027-0300

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This is the fixing motor fault error.
You will need to replace either the fixing motor, the DC controller or the main Power supply PCB.
There is no reset for this fault.

This error means that the Fixing heater is not working. It has not reached operating temperature after a specified time. It has probably blown the heater element.
You will need a trained technician to repair this.
E000 errors will not clear until the fault has been rectified and then reset by a technician. This is to prevent any fire risk.

Please check the main thermistor TH1 has poor contact or open circuit.,the thermal switch is opened.In this case the fixing heater has opened and the SSR is faulty.
For the reset : COPIER-FUNCTION-CLEAR-ERR.

E808 A fault in the fixing drive circuit or the power supply unit is
detected

check the fixing rollers maybe some adhesive materials left on the roller and cause the fixing roller not to rotate smoothly. or some drive gears broke during printing on heavy media