Hey all,

I have a friend who owns a Prarie 650. In the past, 4x4 engagement wasn't precise, but this last weekend, it wouldn't go into 4x4 at all. We rode about 32 miles with it switched to 4x4 mode the whole time, but it never would go into 4x4. I was wondering what the service manual stated as a troubleshooting guide for the 4x4 engagement. We have the bike torn down most of the way to look at the wiring, but can't find anything. His brother and father also own 650's, so we interchanged most all of the relays with one of theirs........and this did not fix the problem. We even swapped the servo motor without any luck. They have a service manual ordered, but we're planning a ride for Saturday.......not sure if the service manual will get here in time. Thanks in advance.

Waylan

 

I have a service manual, but I'm not sure if I'll be of any help.



"Troubleshooting K-EBC and selectable 2wd/4wd system malfunction:

Actualtors failed
speed sensor short or open
forward/reverse detecting sensor short or open
actuator controller failed
controller 10A fuse blown
battery disconnected"


The first thing I would check would be the fuse. Is there power to the servo?

 

Thanks so much. Do you know where the fuse is located? It is hard to test for power to the actuator since the wheels have to be moving to send power to the actuator. We tried everything. The actuator works. We swapped the speed sensor with one from his dad's bike. There are only 2 things we didn't swap........one was the forward/reverse sensor, located behind the coolant overflow bottle........the other was the "diode" as Kawi calls it...this is located on the relay panel under the shift ****. Again, do you know where the 10amp fuse is located? Thanks again,

Waylan

 

As far as I know, all the fuses are located under the seat. You'll see a pack of standard auto-type fuses and there is also a big main fuse.

If you need any more info or diagrams from the manual, let me know and I'll see what I can do.

 

Walexa, The fuse is in the main fuse block. If the controllers fuse was blown, there would be a lot of things not working I think. Remove it and turn on the machine to test this. If the speed sensor didn't work, you would probably see "0MPH" on the display all of the time. You may be able to test the forward/reverse sensor by observing the K-EBC system. It is supposed to work in forward motion, but not reverse, and between something like 2 and 12 MPH. If it functions properly than the f/r sensor is probably good. The 4wd servo is sent a voltage signal rather than simply being turned "on". It is a ramping voltage to move the mechanical linkage. It tries for a period of time (3secs? - it is in the service manual) and then pulls back for a few seconds, and then re-tries to engage. A position feedback voltage is read from the servo by the controller to "know" when it has accomplished engagement, then after a period of time it indicates 4wd on the display. This is from memory so I need to check the manual to be sure. Anyway, if you raise the ATV off the ground securely with jack stands or something, you can run it and see what happens. If the servo is trying to move, than all of the sensors are O.K. About the only thing left to make it function is for it to physically be able to move the mechanical parts into the 4wd position and for the servo position signal to be read by the controller that this movement is complete, so that it doesn't try to pull it back to the 2wd position (you should hear this or feel the vibration of this it if you touch the servo. I think that the controller will flash a error indicating sequence if it doesn't read any change in the position feedback voltage, I need to check that. I hope this helps and let me know what you find out.

 

Thanks for the info guys.

We spent all day Saturday trying to figure it out, and here's what I know: We swapped out all fuses/relays/etc that are plugged into the wiring harness, except for the forward/reverse sensor, which is located behind the coolant overflow bottle, and the plug-in that Kawi refers to as a diode. We pulled the actuator, which is bolted to the front differential, and set it up on the atv. This way, we could watch any movement it might make. Testing on another bike, if the atv was moved back or forth for a certain distance, the actuator would move into the 4x4 position. Switching to 2wd, it went back to the 2wd position immediately. It did not work at all on the bike that is having problems. With the harness unplugged from this actuator, and with the bike jacked up and tires turning, no power was indicated to be going to the actuator. The week before, his bike had started doing the grinding in low range when decelerating, so I adjusted his shift linkage so that it would work smoothly.......I shortened the linkage in essence. He had no problems the next night on a ride, but this last ride we took, it wouldn't go into 4x4.......even though he had it switched to 4x4 the whole time. The problem definitely isn't in the actuator, since his actuator cycled when plugged into his dad's harness. All fuses are good, and we even changed out the speed sensor with the one on his dad's. His dad's continued to function properly with all the changed out components. I believe it is in the reverse sensor. In the previous ride, when stuck and in reverse, even with the override button pressed, his kept backfiring violently. I thought he just wasn't using the override button, but he said he was. One other item to clear up is that the mechanical innards that are moved (some sort of slider dog) works smoothly by hand, so that's not the problem. Anyway, any suggestions are welcome. It was very tiring to try to figure it out without the manual Saturday. The front fenders are removed, and all the wiring harnesses looked good. No burnt spots that we could see. Anyway, thanks again.

Waylan

 

I was wrong about the servo signal, it is switched "on" and it is the position or potentiometer voltage that ramps up according to how much it turns. If the servo is not getting switched "on", make sure the 2wd/4wd switch is working. If the ATV was limiting speed in reverse, than it must have known it was going in reverse. I think that the controller reads the direction from the sensor, not by the shifters' position. I will check this tonight, but to switch on the actuator, you need to switch it from 2wd to 4wd and be moving between 1kmh and 20kph. I don't think it cares about forward or reverse. I have shifted into 4wd before when backing up a hill. The "slider dog" has three "ears" on it that have to engage another part. Unless you stop with it lined up, you will have to move it while it is trying to find "home". This must be why it requires at least 1kph to work. If you can read speed changing on the display, then check the 2wd/4wd switch next.

 

prarie633,

Thanks for the info. We checked the switch itself, and it is very simple......nothing more than a contact between 2 wires, and it was very clean.

On the topic of reverse: There are 2 sensors that relate to reverse. One is mounted on the engine case behind the coolant reservoir. This sensor is called the reverse indicator sensor, and simply indicates whether or not the machine is in reverse..........sends power to the reverse light, and activates the reverse speed limiter. The other sensor is also behind the coolant reservoir, but lower on the engine. This sensor is called the forward/reverse sensor, and is the one that controls power to the actuator. Without it detecting that the bike is moving (either forward or reverse), it will not allow power to the servo. They got the service manual in last night, and we're planning on working on it this afternoon.

One thing I would like to know about the forward/reverse sensor is this: is this particular sensor an open or closed circuit. In other words, what would be the sure fire way to test to see if it is bad? simply unplug it and see if the bike will immediately go into 4x4, or jumper across it? I understand that it may not be that simple, and either the part is good or bad, and the controller may be looking for a certain voltage to operate the actuator. Anyway, thanks for your help. This has all been confusing, but I think we're getting it ironed out. I will post the results of tonight's work so that it may help someone in the future.

Thanks again,

Waylan

 

I'm going to look at this in detail tonight. I think it uses the speed sensor to detect movement. This is probably a hall effect sensor that sends out a pulse when in the presence of metal, in this case a gear tooth. The forward/reverse sensor is the same type, but looks at a plate mounted on a shaft. You can see pictures of this plate in the service manual. The plate is made such that rotation direction determines two distinct pulse patterns which the controller can decode as forward and reverse. The sensor is probably powered by 12VDC and sends out a short 12V pulse when activated by the plate. This may be a 0 to 12VDC pulse or it could be a 12VDC to 0 pulse. You might be able to read the pulses with a logic probe or voltmeter, but to really check them you would need an oscilliscope. You should be able to check it indirectly by testing another function that uses it. Look at the front of the service manual where the timing diagrams are for the braking system and 4wd shifting. I think the braking depends on reading a forward direction. It shows what is needed for both of the systems to work. Also did you check the switch for continuity and/or voltage with a meter?

 

We checked the switch with a test light, however, it didn't show any power. I believe the power comes from a sensor and goes to that switch, possibly the forward/reverse sensor in question. Without the tires turning, power might never reach the 2/4wd switch, and that's something we didn't take into account when testing it. I do know that if a kawi 650 is in 4x4, and you ground the green wire going to the 2/4wd switch, the bike will immediately go back to 2wd mode. I also know that the bike will go into 4x4 by rolling forward or reverse, so that is why I believe there is a problem with the f/r sensor. Again, any help is appreciated.

Waylan