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Discussion Starter · #1 ·
2014 trx420FA1. When I turn key switch to on without cranking, the radiator fan and engine temp light is on. My code is blinking 8 times. I went to move computer and radiator fan turned off. Also last couple of weeks I e had shifting problems, code 21,22 and 23. Installed new shift motor and 3 diffferent angle sensors and have same problem
 

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Welcome to the forum

I have no experience with the 14 FA and do not have a service manual for it, so I will not be able to help much. Maybe one of the other members can offer suggestions other than "take it to the dealer", but unless you have the diagnostic tools and a degree in electronics or Honda School training, taking it to the dealer might not be a bad idea.
 

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Welcome to the forum

I have no experience with the 14 FA and do not have a service manual for it, so I will not be able to help much. Maybe one of the other members can offer suggestions other than "take it to the dealer", but unless you have the diagnostic tools and a degree in electronics or Honda School training, taking it to the dealer might not be a bad idea.
I can get around one pretty good just not sure about ecu. Been ohming everything out and haven’t found problem. Too many damn sensors on this model
 

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I do have a degree in electronics, but without the service manual or the wiring diagram, I can't tell you what functions the ECU is responsible for. Looking at a 500FA diagram, the ECU does control the cooling fan. Find the sending unit for the fan and see if unplugging it will shut off the fan - if not, ground the sending unit wire and see if that shuts off the fan - typically the ECU is looking for a high or low bias to turn the fan on and off - depending on how it's wired and programmed, it might need a variable voltage signal to function properly - wiring diagram will reveal that.
 

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I do have a degree in electronics, but without the service manual or the wiring diagram, I can't tell you what functions the ECU is responsible for. Looking at a 500FA diagram, the ECU does control the cooling fan. Find the sending unit for the fan and see if unplugging it will shut off the fan - if not, ground the sending unit wire and see if that shuts off the fan - typically the ECU is looking for a high or low bias to turn the fan on and off - depending on how it's wired and programmed, it might need a variable voltage signal to function properly - wiring diagram will reveal that.
I’ll keep checking, I’ve got a bad connection somewhere, or either ecu is fried
 

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I’ll keep checking, I’ve got a bad connection somewhere, or either ecu is fried
The fan didn’t start doing that until I wiggled the wires and disconnected the EOT sensor to put dielectric grease in there. It did shut off when I grabbed ecu to put it back. But now it’s back on and can’t get to shut off
 

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If you suspect the ECU as a problem, try to find a known good used one and plug it in to see if the problem disappears, then put your ecu in the donor vechicle to see if the problem appears on it. The only test for a faulty ECU is to replace it with a known good unit.
 
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