Cat d6k wiring issue

[Ruahines]

We have a d6k with a supposed pilot solenoid fault.
We replaced solenoid and still have the fault.
I am after any help with a wiring diagram as I believe it could be a harness issue.
Fault code is MAchine ECM 133-6
serial no is FBH 344

any help will be greatly appreciated as the little dozer is stuck in the scrub and won't go anywhere.

 

[newguy2k3]

That is a "current above normal fault" meaning either the coil is shorted out, which y'all changed, or the + wire to the solenoid is shorted to ground somewhere. 915 greenn is the - wire and h708 orange is the +. They run to pins 3+4 on the j2 connector of the machine ecm which is mounted above the batteries inside the RH panel on the cab. The connectors on the ecm are J1 and J2, J1 doesn't have any wires in 3 or 4.

 

[Ruahines]

Much appreciated Newguy.
I will check the continuity on the wires tomorrow and let you know what the answer is.

 

[Nige]

Once you have 3 posts on the forum you will be able to send Private Messages (PMs). Let me know your email address by PM. I wouldn't post it here unless you want your inbox to be deluged with spam.

 

[Ruahines]

Ok, so I did the continuity checks. Orange H708 shows 0.2 ohms and green 95 shows 0.1 ohms. No crossover between them so I am guessing it is not a wiring issue.

I am coming to this problem after others so I am having to check basics first.
Control centre is showing the ECM 133-6 as active so I will have to deal with that first.
Can it be cleared/deactivated without the CAT interface?
Lots of other questions but this is going to be a logical step by step thing.
Once again all help is appreciated.

 

[newguy2k3]

Did you check continuity from one end of the wire to the other or to ground? The -6 code is telling you that either the coil is shorted out or the + wire, h708 orange in this case, is shorted to ground. Or the ecm has failed. This is unlikely, repeat troubleshooting steps.

 

[Ruahines]

I forgot to mention that in the response.
With both plugs disconnected there was no short to ground on either green or orange.
Both wires are continuous and there is no short between them.
With the solenoid connected there is 33 ohms showing across pins 3 and 4.
With the solenoid unplugged and a bridge in the plug, pins 3 and 4 are showing 0.4 ohms across them.
All of which suggests to me that the wiring and the solenoid are ok.

Thanks

 

[Ruahines]

I got a chance to go back to the machine late this afternoon (it is stuck in the bush 25 kms away)
I thought that I should also check for shorts to other wires in the harness.
Starting with the both the solenoid and the ECM unplugged I tested for shorts against pin 3.
7 other pins have resistance of less than 10 ohms.
I assumed that the harness is a mess somewhere and didn't worry about checking on pin 4.
Tomorrow if I get the time I will stand it up on the blade and rippers, block up the tracks and crawl underneath to drop belly plates.
Then I should be able to get a good look at the harness and see whether it has any obvious damage.

I will keep you informed.

Thanks for all the help so far.

 

[newguy2k3]

If pin 3 is the ground wire it's very likely that there would be continuity to some of the other pins. Cat uses common ground wires for solenoids and switches off of exams quite a bit.

 

[Ruahines]

A generous member of the forum sent me the circuit diagram and the fault diagnosis procedure.
Pin 3 should not have any resistances to other pins below 5K ohms. So seeing as I had already done that check I started looking for harness faults.
,
Blocked it up dropped belly plates and ran fingers over harness looking for breaks/bumps etc.
All felt good so I started disconnecting plugs on the way up from solenoid to ECM and checking for the fault.

Round plug under right foot area let dust drop as I loosened it so immediately I felt like I was on a winner.
Here in the outback of West Australia the dust is so fine it gets in places that should not be possible. Plus it is red from the iron so it causes no end of problems.

Cleaned contacts and tested, all was good. Reconnected and tested to ECM plug, all is good.
Dozer started, park brake disengaged and tracks turned.

Motto of the story is never believe what others tell you they have done in diagnostics. Check it for yourself and assume nothing.
I could have saved a lot of time by checking plugs at the start but was told by others that they had checked all of them.
This little dozer has been sitting idle and not earning its keep for several weeks needlessly.

Anyway I really aprreciate the assistance that was given and hope that I can reciprocate in the future