CAT 725 ADT

[Nik54]

Good day to all,
I have problem with CAT 725 which is converted to water bowser.It worked like that for quite while,since new owner bought it,it came out from low bed in reverse,but that was last time,now it is refusing to go to reverse.Comand is accepted,reverse alarm is on,display indicator is showing R,but machine does not move.Forward is moving.Confusing thing for me is the red bucket light on the dash,according to service manual is ON when hoist lever is not in floating position.Since I could not find proper operators manual to read proper handling of the hoist lever,I think signal which keep the light ON is avoiding activation of reverse solenoid.But I am just guessing.Does anyone knows something more about hoist lever operation.I tried to move in all positions,light does not go OFF,signal wire is changing the value when you move it trough all positions.On the display there is only code E329,which is according to the manual clogged transmission filter.
Many thanx in advance
Nik

 

[kshansen]

Do you have a full S/N? SIS shows around 11 different S/N prefixes for a 725 and that is just what shows up on the USA SIS pages no idea if there are different versions for other areas of the world!

 

[Vetech63]

Not sure on this Cat, but other manufacturers I've seen use a proximity switch on the bed/frame to indicate that the bed is fully down. If I remember right, when the light is on, some transmission functions are not available. Make sure there isn't dirt or debris between your bed and the frame preventing it from lowering all the way. Make sure the proxy switch hasn't been damaged or covered in dirt. That is where I would start.

 

[Nik54]

Not sure on this Cat, but other manufacturers I've seen use a proximity switch on the bed/frame to indicate that the bed is fully down. If I remember right, when the light is on, some transmission functions are not available. Make sure there isn't dirt or debris between your bed and the frame preventing it from lowering all the way. Make sure the proxy switch hasn't been damaged or covered in dirt. That is where I would start.

Do you have a full S/N? SIS shows around 11 different S/N prefixes for a 725 and that is just what shows up on the USA SIS pages no idea if there are different versions for other areas of the world!

 

[Nik54]

Thank you for both suggestions,regarding one from kshansen,S/N is CAT00725,CAFX01486,to be honest I don't know name for the second number.And its made in UK,but I don't think there is much difference between the markets regarding general stuff,maybe something regarding different climate,could be A/C system,cooling systems etc.One from Vetech63,maybe you didn't noticed,that I said that machine was converted from ADT to water browser.I thought the same,and went under the machine fro the swiwel area to the back,hoping that someone didn't isolated properly proxy sensor or switch or whatever else is used to detect where the bucket is.To my surprise there was nothing,no branch from the main loom which is for lights at the back.Than I found in diagram,on the hoist lever its position sensor which is changing voltage while moved from one end to the other one,from front side to the back.That lever have 2 position preset(you fill click,like it locks) somewhere around in the middle between far back and far front position.Voltage is changing gradually while lever is moved,but I was not able to find in that manual what right values are,plus I couldn't see in the diagram anything else what can detect position of the bucket,no sensor nor switch.That solution for signal only from lever position,for me it does not seems much accurate,if something goes wrong along the line mechanically,ECU is receiving signal that bucket is up but actually bucket may be still down.OK for now is irrelevant,because of the conversion, but it could affect normal operation of the transmission.

 

[kshansen]

Good news is that S/N does show in SIS AFX01486 that is the S/N.

Well I'll start with attaching the hoist control operation section from Op/Mant manual.
I do have the electrical schematic if you want to "start a conversation" and give me an email address to send it to you.

 

[Nik54]

I do apologize,I posted your reply again by mistake,w/out comment.
Sorry.

 

[Nik54]

Good news is that S/N does show in SIS AFX01486 that is the S/N.

Well I'll start with attaching the hoist control operation section from Op/Mant manual.
I do have the electrical schematic if you want to "start a conversation" and give me an email address to send it to you.View attachment 193089

Thank you so much,I appreciate it indeed.
My email is micanikolic@gmail.com
Regarding machine ID,belive me,I took that data from the machine ID plate,in the field S/N it was CAT 00725 another field does not have name,just AFX01486.
Sir,for now it would be beter hoist operation,cheking sensor and all components involved.I have diagram already.
Thanks a lot and kind regards

 

[Nik54]

Thank you so much,I appreciate it indeed.
My email is micanikolic@gmail.com
Regarding machine ID,belive me,I took that data from the machine ID plate,in the field S/N it was CAT 00725 another field does not have name,just AFX01486.
Sir,for now it would be better hoist operation,checking sensor and all components involved.I have diagram already.
Thanks a lot and kind regards

Sir,what I saw now,when I read note and operation of that system,hoist lever on that machine is not spring-loaded. But manual says that is spring-loaded.Wherever you leave lever it will remain there,but unfortunately that is not problem,because sensor is attached at one side and changing voltage,but I do not know values.
Thanks

 

[John C.]

Artic trucks that have been custom modified to be used as water trucks are usually done by third party companies. Ground Force is the big company in Post Falls, Idaho that obtains new or used vehicles and the modifies them into water trucks, fuel and lube trucks and other specialized units. Is there anything on the tank that might indicate the company that did the build into and water truck? That is likely the place where you will find answers about changes in wiring and operation.

 

[Nik54]

Hi to all,and my apology for late reply.I wasn't feeling well for a while.Thank you John C,that is exactly what happened here with this truck.It was modified in reputable company in South Africa,and it was working after that.When it was sold second time,just upon arrival on site it come down from the low bed reversing and that was last time moving into the reverse.
When I contacted them they promised help,but even now I never get something from them.
First I didn't knew how hoist lever works,then kshansen sent me manual,with it I was able to recognize all four positions of the lever.I suspected first hoist lever sensor,even checked operation,voltage is changing quite smooth,and after all,if its problem with the sensor,it will log trouble code. But one thing is surprising me,its first time to see something like that in CAT manuals.When I look at wiring diagram(I bought a manual)hoist lever position sensor signal is connected to connector J1 pin 2. But looking at the trouble code 0773 which represent Hoist lever position sensor,on that just sensor diagram signal wire is connected to J2 pin 15.
Please,have a look at the attachment.
Now,indeed I am stuck,I do not know where and what to check.That light on the cluster is on,bucket is not in a float position,and reverse gear is not engaging.Does anyone know,is that light obstructing reverse to engage,because when shift lever is in reverse,
indicator in the display is showing R,backup alarm is on,but truck is not moving.For me it would make sense that bucket position is obstructing reverse. IF I didn't see R in display and if rev alarm remain silent.Now I am afraid of the scenario that,it was working all the time before like that,bucket light was just ignored,as there is no more bucket but now suddenly mechanical problem happened which is causing reverse not to engage and we think problem is electrical. I think if someone knows well how is ECU programmed,it can give us answer.
Any suggestion is more than appreciated.
Regards

 

[Nige]

I think the electrical schematic that is in your manual may not be the correct one for your machine AFX01486.
I am looking at the online schematic for AFX01486 and it shows Wire M996 Pink for the Hoist Lever Sensor connected to J2 Pin 15, and Wire J764 Brown for 8V sensor return connected to J1 Pin 45. This is exactly the same as what the Troubleshooting procedure shows. I have your email so I will send ia copy of the schematic to you.

The hoist lever position sensor is a PWM sensor. Testing voltage at the sensor will not show anything that could be used for diagnostic purposes, that requires a digital multimeter that can read/interpret a PWM signal. The possibility exists that the sensor is sending signals that are in the "correct" range in order to not log a Diagnostic Code, but the signals are in fact "wrong" and the hoist control sensor believes that the lever is not in the "Float" position, therefore it indicates that the body is "Up" and will not permit reverse gear to engage.

The hoist control should be spring-loaded in 2 directions. First, when it is pulled to the "Hoist" position if you release the lever it should return to the "Hold" position by one spring. Second when you push it into the "Power Down" position it should return to the "Float" position when the lever is released. Unless the lever is in the "Float" position you cannot get more than first speed forward. Can you get all the forward gears on the truck..? If the answer is yes then I suspect the problem is not in the hoist control and is probably in the transmission. Personally I would get the hoist control working correctly and then move on from there.

Changing the subject completely. Have you inspected the transnmission suction screen for burned clutch material and have you checked the transmission oil for a burned smell..? If you have no Diagnostic Codes in the Power Train System I think that might be my next move, even if it was just to eliminate the possibility of a failed clutch.