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Discussion Starter #1 (Edited)
Recently serviced the trans on my bike which required complete removal and re-installation of the motor and most of it's associated components. After getting the motor, and the wiring and fuel systems connected I encountered a fault code 38 on the tach. This is for the decompression solenoid. The fault can be caused by an open circuit and/or an ECU failure.

Assuming the ECU was fine I worked on the possibility that there may be a problem with the solenoid. I removed the solenoid with wire harness and bench tested it. There are 4 wires connected to the solenoid, two are for actuating the solenoid and the other two are thermostat wires built into the solenoid.
The black wires actuate the solenoid. The green wires don't. The solenoid is not serviceable BTW, so if it doesn't work one is to assume that the thing is toast and needs to be replaced. Here's where I found out that there's an issue with the harness which is wrapped in a sheath.

After failing the bench test I tried a continuity test from the black connector to the exposed wires three inches before they entered the back of the solenoid. The first wire failed continuity which meant I had to remove the sheath and expose the wires. About 6 - 8 inches from the solenoid there are two crimp connectors on the black wires which are only electrical taped to protect from the elements. Turns out this is where the wire separated. The elements corroded the exposed wires and one broke when I was removing and replacing it back on the bike. The harness is also protected by a wire loom, but all this protection essentially keeps moisture the harness.

The repair was simple, cut and solder the connection then shrink wrap the area after placing some dielectric grease on the connection. (Bench test the repair to make sure the solenoid actually works.)
Since the sheath was removed I electrical taped the 4 wires all the way up to the connections under the seat and placed the harness back into the loom that contained the cam gear sensor.

The removal can get involved and I'm sure less parts can be exchanged but I pulled the pulley housing off, removed the battery box, and removed the sub fuel tank to re-route the wiring harness properly and with ease. Zip-tie the harness/loom back onto the frame below the transfer case and place the all the wire harnesses back in the clips on the seat tube. Attach all the parts you removed and connect the harness, battery, and ECU.

The part retails for 206.00 -ish but can be purchased as low as 133.00-ish if you shop around. I know of a friend who had to replace this because the dealer didn't check the harness. This can save you a chunk money in labor costs as well as the part cost if you bring this to a dealer for service.

Wiring diagram courtesy of Alanh:
 

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This is awesome to know and should ABSOLUTELY go in the "popular mods and repair knowledge base".

Great write up, review and technical description. Excellent info to have for all DIY repair/service Warrior owners.

Thank you!
 

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Discussion Starter #7
I was so pissed (not drunk for you overseas mates) when I found this, that I had to post it up. I have seen this before on this bike and also on my R1's harness. It's been a while since I had to put my thinking cap on (usually a drinking cap) to diagnose a failed part which was functioning just prior to doing the some sort of service work. I have no idea why this would not have a solid connection to the solenoid from the under-seat connection other than to build in some degree of failure for future parts and service revenue.

I saved myself a chunk of change, that alone was worth the effort. I hope this failure doesn't come across your path but if it does, you'll have some knowledge about a possible cause for the failure and how to repair it.
 

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Excellent trouble shooting and neat technical write-up ... thank you :)

Why don't you retitle this thread and place it as a sticky in the : How To's and General Maintenance Tips
 

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JP, Great write up!

1 question, Do you think the wires in question might have become brittle due to being subjected to high heat cycles and vibration? Which could cause the insulation to crack and expose the wire to moisture, corrosion, then failure.

The reason I ask, is I've noticed over the years and miles on various bikes, the insulation on wires subjected to high heat cycles and vibration become very brittle and then componet failure.

For example Pick up coils on Yami XS1100's and Hall Effect Sensors on BMW's. (same thing)

I finally found some High Tempature Teflon Insulated wires and was able to fix these issues and like you, save money.

In case of the BMW, well over a $1000.

FYI, This Wire is very expensive to buy because you have to buy it in 200ft rolls. I found Ford Electronics in Fullerton CA sells it by the foot, in any color combination and wire dia.

I have often wondered if the CPS failure was due to this issue?

Again nice write up.

G
 

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Discussion Starter #10
Thanks.

To answer your question, no. In this case the wires were butt spliced from the factory as a continuous wire with a crimp connector and were susceptible to moisture because the splice was never insulated properly. I suppose if I never moved the wire I might have gotten another year or two out of it. Removal from the wire loom wasn't necessary and in retrospect I don't know why I did this as I could have kept the whole bundle together. I suppose my thinking was that the solenoid connection may have become brittle, so it was to prevent what I directly caused where I assumed it wouldn't happen. I foresee it failing again because the repair IMO, isn't as good as a continuous insulated wire, although it's a far sight more thorough than what was done originally.

JP, Great write up!

1 question, Do you think the wires in question might have become brittle due to being subjected to high heat cycles and vibration? Which could cause the insulation to crack and expose the wire to moisture, corrosion, then failure.

The reason I ask, is I've noticed over the years and miles on various bikes, the insulation on wires subjected to high heat cycles and vibration become very brittle and then componet failure.

For example Pick up coils on Yami XS1100's and Hall Effect Sensors on BMW's. (same thing)

I finally found some High Tempature Teflon Insulated wires and was able to fix these issues and like you, save money.

In case of the BMW, well over a $1000.

FYI, This Wire is very expensive to buy because you have to buy it in 200ft rolls. I found Ford Electronics in Fullerton CA sells it by the foot, in any color combination and wire dia.

I have often wondered if the CPS failure was due to this issue?

Again nice write up.

G
 

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Discussion Starter #11
Excellent trouble shooting and neat technical write-up ... thank you :)

Why don't you retitle this thread and place it as a sticky in the : How To's and General Maintenance Tips
I will but I don't think this is a great write up for the novice person. ...and I'm generally too focused to have taken pics. :rolleyes:
 

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Awesome write up! Thank you so much, the key part of what you had to take off to replace it will save me a lot of time replacing my solenoid.

I wanted to know if anyone thought of just making a manual decompression cable just in case the solenoid/wires fails again? All it would have to do is pull the lever that the solenoid pushes on, right?
 

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Decompression solenoid

Hi all need a bit of help with the decompression solenoid
I had a code 38 on the bike so I did some checking

The resistance last night when the bike was warm and it was about 104 ohms.
today it is open circuit and it no longer works.:(:(

Has anybody removed the decompression solenoid when it failed?

the cables run between the oil tank and the fuel pump tank. There are two clips that hold the cables on the oil tank side. I have removed the cover from the fuel pump tank but still cannot reach the second cable clamp.

Do I have to remove fuel tank to get the cables out?

Dave
 

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Hi all need a bit of help with the decompression solenoid
I had a code 38 on the bike so I did some checking

The resistance last night when the bike was warm and it was about 104 ohms.
today it is open circuit and it no longer works.:(:(

Has anybody removed the decompression solenoid when it failed?

the cables run between the oil tank and the fuel pump tank. There are two clips that hold the cables on the oil tank side. I have removed the cover from the fuel pump tank but still cannot reach the second cable clamp.

Do I have to remove fuel tank to get the cables out?

Dave

oh er dave ...not been their my friend ...hopefully a guru will appear ....so BUMP :D:D
 

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Dave, did you check the Diag code set at number '55'.....?

It is a test to see if the solenoid is working or not. Page 6-16 in the book.
It's not the code which appears as '38' on your Tacho.
 

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Yep done that
When I took off the solenoid cover I start the bike but the coil did not move
Checked the resistance and its open circuit

Dave
 

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Dave,

Re-read the original post. I think he mentions that the factory splice is down by the solenoid and did not require removal of the whole harness. I think he mentions that as he speaks of looking in retrospect.

You probably have the same issues.

Worth a try!!
Good luck!
 
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