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Discussion Starter · #1 ·
Recently picked up an 02 Foreman as a project. The 4wd light flashes 4 times
According to the service manual this is a voltage issue at the 4wd controller. The fuse for 4wd is good and I've measured the voltage at the controller on the red and green wires and get 16.6 volts. The service manual says if you have correct voltage on those wires to replace the 4wd controller. So I bought a used one off ebay and swapped it. I get the same error code with the replacement. The 4wd light flashes 4 times. Any one have any other suggestions? Other than spending the $$$'s on a new controller.
 

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Hi Rocketman5144, the problem you are having has to do with the charging system. 16.6 volts at idle speed is excessive and indicates a problem with the regulator/rectifier. You do have a functioning battery in the bike right?

The FCC throws an error code 4 if supply voltage is out of range, either too low or too high. See section 17 of the FSM for charging system troubleshooting. Hpoefully you just have a bad ground or a dirty/corroded harness plug but let us know how it goes...

EDIT: Note that a normal idle speed battery voltage from a fully charged battery in good condition should read no more than 13.5 volts at your volt meter.
 

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ummmm..just for chits and giggles, try this, start it up, put it in gear, see if your 4wd light is working normal ?..lol. ( don't ask ! )..lol.
 

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Discussion Starter · #4 ·
I thought 16.6 was high on the voltage, need to double check that with another meeter.
But it does it with out the motor running. If I turn the ignition on, but don't start the motor after about 30 seconds the 4wd light will start flashing the 4 code. I did try a different battery and it did the same thing.
 

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I thought 16.6 was high on the voltage, need to double check that with another meeter.
But it does it with out the motor running. If I turn the ignition on, but don't start the motor after about 30 seconds the 4wd light will start flashing the 4 code. I did try a different battery and it did the same thing.
did you put the motor in gear ???. when you cranked it up, and tried the 4wd part ?.
 

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Just a suggestion... Start it up and remove the live wire from the battery, in effect you’ll be cutting a set amount of power to everything. I can’t gaurantee this will work, but it might. Worth a shot before spending more money though I guess.
Electronics aren’t my strong point, I’m sure I’ll be corrected if I’m wrong :)
 

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I thought 16.6 was high on the voltage, need to double check that with another meeter.
But it does it with out the motor running. If I turn the ignition on, but don't start the motor after about 30 seconds the 4wd light will start flashing the 4 code. I did try a different battery and it did the same thing.
Does the 4wd actuator work normally if you start the motor right away after turning the key on and drive the bike? No codes are thrown then? If so, there probably isn't an issue with it.

It sounds like you checked the voltage with a bad meter, since the battery can't possibly produce 16.6 volts by itself.
 

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Discussion Starter · #8 ·
It doesn't go into 4wd with the switch according to the indecator. I haven't put it up on jack stands to see if the wheels turn.
 

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It doesn't go into 4wd with the switch according to the indecator. I haven't put it up on jack stands to see if the wheels turn.
i'd be willing to bet, it won't go into 4wd until you run the motor, and put it in gear, and then put the switch into 4wd !.
 

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do this, get it off the ground, all 4 wheels, crank it up, make sure the 2wd/4wd switch is in the 2wd spot, put it in first gear, while switching it to 4wd, watch the light on the dash, as well watch to see if the front end starts to turn :).
 

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I am only saying all of this, because I ran into this sorta problem when restoring my '03 trx450fm, I bought a new 4wd control unit thinking mine was bad ?, come find out, it was after I got the motor started and in gear, that the 4wd light came on, stopped flashing !, and my front end was then working. I think ????????????..its because the speed sensors on these has to see the drive shaft turning ?, in order to engage the front differential.
 
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Discussion Starter · #14 ·
Update.. I checked my voltage with another meter and it is reading 12.5v so the high voltage was just the other meter.

I put it up on jack stands to see if it is turning the front wheels and it isn't. I ended up taking the front fenders off to make it easier to work on and found the wire harness has been hacked into. I cut each of the two wires that had been added to see what happens and my error code changes; as soon as you turn the key on the 4wd light starts flashing 5 times. I connect them back and the error goes back to the 4 code.

In the middle picture there is a green connector down low that doesn't have anything plugged into it, what is it for?
 

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Update.. I checked my voltage with another meter and it is reading 12.5v so the high voltage was just the other meter.

I put it up on jack stands to see if it is turning the front wheels and it isn't. I ended up taking the front fenders off to make it easier to work on and found the wire harness has been hacked into. I cut each of the two wires that had been added to see what happens and my error code changes; as soon as you turn the key on the 4wd light starts flashing 5 times. I connect them back and the error goes back to the 4 code.

In the middle picture there is a green connector down low that doesn't have anything plugged into it, what is it for?
middle pic looks to be the headlight connector, should have 3 wires on it if so ?, blue,white,green ?.
 

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spin the front wheels with it in neutral, if the front drive shaft and all that is good ?, then the rear wheels should turn as well.
 

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i'm stumped here, how does a 2002 trx450 have a 4wd light on the dash ?, I can be wrong here ????? ( like that never happens huh !..lol ) but best to my old memory, Honda did not use the 4wd light on the meter/dash, because there wasn't a 2wd-4wd switch on the throttle to disengage the front drive until 2003. sooooooo..is there a 2wd-4wd switch under the throttle ?, if not ?, then yours is full time 4wd, and there should not be a switch on the bars at the throttle. if there is a switch ( yellow )..then you have at least a 2003 trx450 foreman..or..i'm wrong..lol.
 

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Discussion Starter · #20 ·
spin the front wheels with it in neutral, if the front drive shaft and all that is good ?, then the rear wheels should turn as well.
With all four wheels off the ground if I spin the front tires the front drive shaft is not spinning. The diff is not locked. If I turn the rear wheels the front drive shaft turns as I would expect.
 
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