Bill Hunt
Member
Can anyone tell me where the left drive motor speed sensor is located on a cat 259d???
Dear Nige thanks a bunch for your answer. I hate to sound so elementary but is there 2 drive motors and if so then where is this drive motor located. As you can tell I'm no diesel mechanic but i learn pretty fast. I'm just trying to get acclimated to this recently purchased machine i got. Once again thanks for all who will chime in and help me out on this oneRight on the bottom of the drive motor. The wiring harnes connector should be easy enough to spot.
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Does this help.?
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Nige that is great information. I was able to get the machine on blocks as instructed and surprisingly i saw what appears to be that plug. And it is just hanging. It appears to be attached to the drive motor but ithe other end is not attached to anything. I'll send a picture to see if this is definitely the sensor. Of course it is dirty but it's the best picture i could get. I may be able to clean the area a little better to get a better picture. My question is: what is the other end supposed to be attached to. I assumed it should be attached to a wire coming from the machine but i don't see one unless I'm overlooking it. I also have the cab up as you instructed. Is it possible to send me somewhat of a diagram of what that plug looks like or comes from? Thanks a bunch for your time and patience
Hi Bill, yes two drive motors, one on each undercarriage. Both have speed sensors that need to read correctly.
First thing first... raise the cab and check all plugs and wiring, especially those that branch off to both undercarriages under the cab.
Next, get the machine up on blocks and remove the bolts/plates on your axles that stop your undercarriages falling off. If the bushes aren't seized you'll be able to slide the whole undercarriage out a few inches for better access. 2685-8 is "Unexpected Motor Speed Detection Control" on the LHS motor so start with the LHS.
May need to remove a few hoses to get to the allen head bolt for the sensor, maybe not. Remove sensor, look for any metallic debris. If you cant find anything wipe it clean and swap sensor with the one on the RHS undercarriage.
Three things could happen:
1) Nothing, 2685-8 keeps reoccurring, problem is still in your LHS speed sensor wiring.
2) Fault changes to 2687-8 which is "Unexpected Motor Speed Detection Control" for the RHS, which means the sensor is bad.
3) Fault mysteriously goes away. Could've been tiny piece of metallic debris on the sensor from general wear, or could've been a bad connection somewhere in a plug.
I tried to look at the other side but i couldn't see it. I'll try to look again today at the RHS. And i will most definitely post my S=N and ask Nige to send a schematic. Information is helpful that you've provided thus farThat'll run alongside the hydraulic hoses and through the machine frame connecting under the cab. Easiest way for you I think is to look at the RHS.
That connector (receptacle) and the bit it connects to (plug) are called deutsch connectors. Looking at those photos they will both need to be replaced before reconnecting.
If you post your s/n and ask nicely Nige will probably send you a schematic.
Again this comes back to Serial Number. There are 8 different models of 259D (also plus potentially different sub-models within that 8) and it would be of major benefit to know which one of them you have, not least to help in posting an illustration of what the wiring that connects from the machine chassis to the speed sensor ought to look like.I also have the cab up as you instructed. Is it possible to send me somewhat of a diagram of what that plug looks like or comes from?
That is exactly what happened. I bought it a week ago with this issue already just trying to rectify it and the loud beeping. I just recovered my serial number. It is as follows: CAT0259DPFTL07252. I will try and see what the RHS looks and runs toAnother question. Is this a fault that has appeared suddenly or has it been there for a while now.?
You haven't bought this machine recently with the fault present on it by any chance have you.?
The reason I ask is that my first thought when you said the harness/sensor connector was hanging was that your photo would show torn wiring (possibly not unusual if a tree root or similar has been jammed in there). The fact is that it doesn't, it shows what appears to be an unplugged connector. Based on photo that the "other end" (aka the male half of the connector) should be around somewhere not too far away. Looking at the other side of the machine ought to give you the best clue.
Again this comes back to Serial Number. There are 8 different models of 259D (also plus potentially different sub-models within that 8) and it would be of major benefit to know which one of them you have, not least to help in posting an illustration of what the wiring that connects from the machine chassis to the speed sensor ought to look like.
A lot of head scratching could have been avoided if you'd volunteered that information in the first place...........That is exactly what happened. I bought it a week ago with this issue already just trying to rectify it and the loud beeping.