D5G tracks will not move with flashing code 168 ???

[Richie Nell]

D5G LGP. Tracks will not move at all with light on dash and red flashing code 168. Any ideas? Thanks alot.

Just replaced fuel pump, new batteries, rebuilt alternator showing good voltage, 14.3v. Recently had CAT mechanic replace fuel pump and blow out fuel line to tank due to engine stalling. Appears the tank lining, applied to prevent rust, is flaking off getting into fuel line. So then it was running good until I cranked it one morning and track gear symbol lit up immediately and dozer will not move an inch.


Richie

 

[Nige]

Tracks will not move at all with light on dash and red flashing code 168.

168 refers to the engine coolant temp sensor. Why this should stop the machine in its tracks I'm not sure. See the attached. It might pay you to sort this problem before proceeding further but I'm not sure it will be the fix for your issue.

 

[Richie Nell]

Thank you Sir, I remember the CAT mechanic did see a 168 code on his laptop but machine was running fine at the time.

 

[Nige]

As I said I don't think fixing the coolant temp sensor issue is going to make any difference, but until you do fix it you'll never know one way or the other.

So then it was running good until I cranked it one morning and track gear symbol lit up immediately and dozer will not move an inch.

I wonder if it has stripped the drive coupling (#1 in the illustration below) between the engine and the Hystat, especially seeing as it happened at first startup one morning.? Not exactly an unknown problem. Post a Serial (PIN) Number and I'll take a look at what tests you can do to check for that.

I think there should be a panel on the RH side of the tractor with test points behind it.
Do you have access to pressure gauges.?

 

[Richie Nell]

RKG00669
I do not have test gauges.
Just FYI....the tracks did not lock up while running. It ran and move along properly one day, shut it down over night, next morning cranked it up and would not move at all.

 

[Nige]

Just FYI....the tracks did not lock up while running. It ran and move along properly one day, shut it down over night, next morning cranked it up and would not move at all.

That's what I thought I said. Often the biggest stress on that flexible coupling is a cold startup first thing in the morning, which is exactly what happened to you and then the park brake would not release.

To test whether or not the coupling has failed is going to need a gauge or gauges hooked up to one or more of those test ports.
A quick & dirty test would be on test port #9 (arrowed, bottom left) then start the engine and run at low idling speed. The pressure under those conditions should be around 320psi. If you have zero pressure then the coupling has most likely failed.

 

[Richie Nell]

Ok. Probably be cheaper for me to buy gauges than a CAT mechanic to do it.

Any idea of the simplest gauge kit to do these type tests?

 

[Richie Nell]

New sensor is on the way.

Would a stripped coupling typically throw a code?

 

[Nige]

New sensor is on the way.

Would a stripped coupling typically throw a code?

Be prepared for the fact that a new sensor might not necessarily fix the 168 Code. You could just as easily have a wiring problem which will not be cured by fitting a new sensor. That's why I posted the troubleshooting procedure above - to help you determine exactly what failed......

Any idea of the simplest gauge kit to do these type tests?

See the highlighted parts. 2 couplings, a hose and a pressure gauge.
Effectively those are the Cat Part Numbers that you would need to do a "plug & play" connection to Test Port #9. They will NOT be cheap to buy if you go to the dealer.

HOWEVER, all you REALLY need is the 6V-4143 Coupler illustrated below.
This (or an aftermarket coupler that will connect with the 6V-3965 fitting on the machine) is a must-have because it connects to the existing test port in the panel on the RH side of the machine.
IIRC the female thread in it is 1/8" NPT but don't quote me on that.
Here's a genuine one on eBay. Probably cheaper than the Cat dealer - https://www.ebay.com/itm/125154424305

Then you need a pressure gauge that reads up to 5-600psi maximum, and a hose (or some connectors) that will hook up the gauge to the quick coupler. Then you're all set.

 

[Richie Nell]

Perhaps the correct port is #7 on my machine… pictured.

 

[Nige]

Would a stripped coupling typically throw a code?

No it would not AFAIK. We've been there before on other D5G tractors IIRC. Read carefully through the two thread I have linked below. All the necessary information is there.
The lack of pressure in the hystat system will not allow the park brake to release.

I must admit to forgetting to advise you to test the alternator output voltage before proceeding further. This models is known to do weird things when the system voltage is not up to snuff.

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[Richie Nell]

Gotcha. Thanks

I priced the three parts new at about $270. Any reason this cheap test kit would not work?

https://a.co/d/guEfzZj

 

[Nige]

I priced the three parts new at about $270. Any reason this cheap test kit would not work?

No reason why it will not work apart from the fact that I don't see any connector in that box that will hook up directly to the Cat test point on the machine. You may have to buy the 6V-4143 separately.

 

[Richie Nell]

Ok.

I must admit to forgetting to advise you to test the alternator output voltage before proceeding further. This models is known to do weird things when the system voltage is not up to snuff.

I have learned the importance of proper voltage and yes it is putting out 14.3ish volts consistently with newly rebuilt alternator, belts and batteries.

In my picture of ports above, is #7 the same as your #9 ?

In the kit, I thought the connector they identify as being for “Caterpillar” would fit on machine, no?

 

[Nige]

I have learned the importance of proper voltage and yes it is putting out 14.3ish volts consistently with newly rebuilt alternator, belts and batteries.

OK, so we can rule that out.

In my picture of ports above, is #7 the same as your #9 ?

I'm sorry I do not know for sure. According to the manual for an RKG-prefic machine which is where I lifted that photo the test point I said should be around 32psi is #9. The thing to point out (after revisiting the first of the two threads I linked above) is that if the coupling has failed then there will be no pressure at ANY of those ports.

In the kit, I thought the connector they identify as being for “Caterpillar” would fit on machine, no?

Maybe, maybe not. The problem is that there are a few different styles of quick couplers on different product lines of Cat machines. Is it the end of the world if you have to buy one extra adapter over & above the kit in order to hook it up to your tractor.? Not really........

 

[Richie Nell]

I do understand everything you’ve said. And I do agree, it would not be the end of the world. I have learned a lot here and really appreciate your time.

A year or so ago I had the right final drive replaced. I noticed that testing the pressure ports was part of that process to check if pump was sending power to drive motor. I’m no mechanic at all but should be able to do that.

 

[Nige]

I’m no mechanic at all but should be able to do that.

Just go slowly and if in doubt - ASK...!!

looking again I think that MAYBE the brass connection in the photo might just be the one you need. it certainly looks as though it could be.

The downside of that kit is the lowest pressure gauge in the set of three is rated at 3500psi max, not 5-600psi as required. For sure you're not going to blow up the gauge but when it comes to measuring lower pressures a 3500psi gauge is not going to be quite as accurate as a 600psi gauge. Maybe the best that you can hope for is that if there is any pressure at all at least the needle will jump off the bottom stop just a bit.

 

[Richie Nell]

Thank you

 

[chidog]

I think those gauges pictured above read approximately up to about 700 psi, the thousands numbers are in bar.
I think they would work okay for the lower pressures.

 

[Nige]

I think those gauges pictured above read approximately up to about 700 psi, the thousands numbers are in bar.
I think they would work okay for the lower pressures.

According to the ad linked by the OP the gauges are 250, 400, & 600 bar. That corresponds to 3500, 6000, & 9000psi. The set is really designed for excavator hydraulic testing. The 3500psi gauge ought to work for 300psi, or if as I suspect with a broken coupling the gauge will not move at all.