Can anyone help with a D6R problem?

vegascowboy · Jan 21, 2016

My good friend is having problems and doesn't know where to turn. He relies on his dozer for his income for his family. We have been trying to troubleshoot it but we are at the end of what we know. He does not know computers well so he asked me if I could post this. Here is his description: the Caterpillar serial no. is 3ZN00440. The transmission S.N. is 9RX00856. It is a D6R, 1997 year model. As soon as you start the engine, after about 3 or 4 seconds, the alarm starts sounding and the brake warning light on the dash starts flashing red off and on about a second or so apart. The brakes are locked down and the machine won’t move – when you put it in gear you can tell it puts it in a strain but the brakes hold it. It is some electrical problem. I have the seat our and the floorboards and am trying to clean – blowing with air compressor, etc. – there is a lot of dirt, and gunk all over, and I’m trying to find some wire that might be frayed, etc. but so far haven’t found one. also not sure maybe an ECM problem? Do they sell refurb or used ones? Any other ideas?

Any info would be much appreciated

Thanks

Rick

Mark250 · Jan 21, 2016

Hi Rick, first off we need to determine if there are any fault codes logged or active see picture below in the screen shown there will be the words serv code
this indicates that is an active electrical . to determine the fault codes hold the button indicated until a series of numbers and letters appear there may be quite a few of these numbers but the ones with the word serv code displayed are the ones that are important at the moment

DPete · Jan 21, 2016

As mentioned above, get the code or codes. I had the parking brake switch go bad on mine.

vegascowboy · Jan 21, 2016

He told me that there are some codes like this response says...however, there are none that have the word serv code displayed. The system just fails its initial sweep of all the circuits and shuts down by flashing the light and sounding the warning alarm. That's all I know for now. Dad has a Cat service manual and has tried to retrieve codes by following that the same way your respondent suggested. There are no serv code numbers displayed.

Any ideas?

Thanks

Nige · Jan 21, 2016

vegascowboy said:
He told me that there are some codes like this response says...however, there are none that have the word serv code displayed. The system just fails its initial sweep of all the circuits and shuts down by flashing the light and sounding the warning alarm. That's all I know for now. Dad has a Cat service manual and has tried to retrieve codes by following that the same way your respondent suggested. There are no serv code numbers displayed.

Any ideas?

Thanks

What that sounds like to me is exactly what the machine is supposed to do when you first turn on the key. It's a "self-test" of the panel - first all the gauges swing up to full reading and back down to zero again (probably more than once), all the warning lights flash (including the SERV CODE icon), then finally the Master Fault light flashes and the warning buzzer sounds before the gauges settle at whatever reading is correct for the state the machine is in. For example if the engine is warm then the coolant temp gauge is not going to go back to zero. If the machine is doing all that before the engine is started then to me that sounds perfectly normal.

Try this. Turn on the key and let the panel go through the self-test until it completes by flashing the Master Fault light and sounding the buzzer. Do not start the engine. First question - is the SERV CODE icon illuminated..?

Then with the key still on and the engine stopped press the black button with the tick mark above it as per Mark's photo above. Note all the groups of numbers that appear and post them back here. To move from one code to the next you will have to press the button each time. The groups will be something like 030 096 F03 or 113 299 F07 just as a couple of examples. Also for each group of numbers note whether the SERV CODE icon lights up or not.

vegascowboy · Jan 22, 2016

Nige said:
What that sounds like to me is exactly what the machine is supposed to do when you first turn on the key. It's a "self-test" of the panel - first all the gauges swing up to full reading and back down to zero again (probably more than once), all the warning lights flash (including the SERV CODE icon), then finally the Master Fault light flashes and the warning buzzer sounds before the gauges settle at whatever reading is correct for the state the machine is in. For example if the engine is warm then the coolant temp gauge is not going to go back to zero. If the machine is doing all that before the engine is started then to me that sounds perfectly normal.

Try this. Turn on the key and let the panel go through the self-test until it completes by flashing the Master Fault light and sounding the buzzer. Do not start the engine. First question - is the SERV CODE icon illuminated..?

Then with the key still on and the engine stopped press the black button with the tick mark above it as per Mark's photo above. Note all the groups of numbers that appear and post them back here. To move from one code to the next you will have to press the button each time. The groups will be something like 030 096 F03 or 113 299 F07 just as a couple of examples. Also for each group of numbers note whether the SERV CODE icon lights up or not.

Thanks for your help guys. Here is his reply. I'm sure this is all such a pain. He hasnt been able to get to work over this junk!

*****************
Yes I have pushed that button many times and got all the codes – the ones beginning with030 are related to the engine. The ones with 113 are related to the transmission and brakes, etc. When the engine starts and it shows the hours, “Serv code” shows up with it. when I press the button and go into the codes, (there is about a dozen) it scrolls through all the codes and no “serv code” ever shows up on the list. That is what is frustrating. I had installed a new brake pedal position sensor back in October and the brakes started working properly for a while, then quit again in Dec. It then showed a “serv code” for the position sensor, so I replaced the one I bought in Oct. since it was still under warranty, and it still shows the code (I think 113 298 or 498 ) but doesn’t say “serv code” any more but the brakes did not start working and the warning still flashes and beeps. I also installed a new brake microswitch and it didn’t help either.

Mark250 · Jan 22, 2016

hi , some codes need the machine to be operated to show the serv code. if you just start the machine and look at the code list displayed it may not be accurate until the machine is put in gear and operated
mark

Nige · Jan 22, 2016

So now we're getting sonewhere. Work has been done on the tractor electronics and now there is a problem with the brakes, maybe the work on the electronics was done in an attempt to fix a brake problem and has been unsuccessful. How is it that the full story never comes out righ from the start...?

Can you ask the owner or whoever is working on the machine exactly what were the original symptoms on the and how did they first manifest themselves..? Did the problem start all of a sudden or did it gradually get worse over time..?

Also, and despite the fact that are none of the Diagnostic Codes in the list have the SERV CODE icon lit - please give the list of Codes with 113 (transmission control) prefix that are on the machine even though none of them are Active right now. It will help to see what has been registered on the diagnostic system.

A thought for all our other contributors. AFAIK on these electronic tractor transmissions the transmission won't engage into gear without the park brake being released first, or am I off base with that...? However the OP seems to suggest otherwise. Is that a clue..?

Nige · Jan 22, 2016

Mark250 said:
hi , some codes need the machine to be operated to show the serv code. if you just start the machine and look at the code list displayed it may not be accurate until the machine is put in gear and operated
mark

Good point Mark, especially the ones related to the secondary brake microswitch. Thinking about that, that switch has 3 contacts, common, normally open, and normally closed. In this tractor the wires are connected to common and N/O, the switch contacts close as the service brake pedal almost reaches the bottom of its travel. If the wiring on the new switch was connected to the N/C terminal that would screw things up........

dblaneyfan · Jan 22, 2016

Nige said:
...A thought for all our other contributors. AFAIK on these electronic tractor transmissions the transmission won't engage into gear without the park brake being released first, or am I off base with that...? However the OP seems to suggest otherwise. Is that a clue..?

Indeed Nige, the parking brake engages both left and right brakes and shifts the transmission into neutral.

Vegas, please get a complete list of codes from the owner, problem could be with wiring, solenoid, switches, etc (could even be just a problem with a ground), but need somewhere to begin.

Best

Nige · Jan 22, 2016

dblaneyfan said:
Indeed Nige, the parking brake engages both left and right brakes and shifts the transmission into neutral.

Vegas, please get a complete list of codes from the owner, problem could be with wiring, solenoid, switches, etc (could even be just a problem with a ground), but need somewhere to begin.

Best

So maybe, just maybe, the problem could be with the secondary brake switch operation (controlled from the brake pedal) that is simply another way way of applying the park brake but will not have the same effect as the park brake does in that it doesn't neutralise the transmission.......

dblaneyfan · Jan 22, 2016

Yes Nige, but the switch shouldn't set off the alarm automatically until the pedel is depressed, unless the microswitch is shorted internally or a wire is shorted. The service brake position sensor should not set off the alarm until it is depressed, unless there is a short. It could also be the parking brake solenoid causing the issues.

Nige · Jan 22, 2016

dblaneyfan said:
Yes Nige, but the switch shouldn't set off the alarm automatically until the pedel is depressed, unless the microswitch is shorted internally or a wire is shorted.

Or unless the wiring to the contact side of the switch is connected to the wrong terminal - normally closed instead of normally open. That would set off the alarm without pressing the pedal as soon as the engine was fired up because the pedal position sensor would be saying one thing and the switch another. That switch has 3 terminals but only two of them are used. I know from personal experience how easy it is to connect wrong.

vegascowboy · Jan 22, 2016

Here is more info. Im sure this is getting complicated:

that there is no way to get past starting the engine. Once the engine starts up, the brake warning light and buzzer immediately sound, and keep the trans locked out. The diff-steer nor the brake release button beside it will affect anything. No way to operate the machine, other than the blade and ripper hydraulics. The lights work fine, the guages work fine, the engine runs fine. The machine was working in the bottom of a pond being constructed at the time when the brake suddenly locked down with the sound of the warning buzzer. It hasn't moved since. For almost 8 years now it has been periodically doing that in the middle of working. But always before, we could just pull up the park brake button beside the diff-steer and it would then reset and go. It got worse over the years, and had to be done several times a day. For a while it had been setting low voltage codes, and foot brake position switch codes, but then they would clear. I have talked with Cat numerous times and retrieved the codes and cross checked with our Cat service manual, and was never able to find a hard fault anywhere...only intermittant. I suspected a bad connection, ground, or wire or sensor or solenoid. I've been able to dertermine nothing all this time. But now that it is locked down and not resetting, so to speak, we still cannot find anything. So we replaced the foot brake position switch (potentiometer) and then the foot brake full stop micro switch to no avail...we even replaced the new position switch again in case it had been defective. Nothing. No codes, no bad readings so far.

Thanks

DPete · Jan 22, 2016

I think it's the parking brake switch or switch adjustment, why it doesn't throw a code I don't know. Maybe a Cat mechanic can plug in and find a fault code that for some reason doesn't display on the dash.

Nige · Jan 22, 2016

So what I think you're saying is that when the warning buzzer sounds and the Master Fault light is flashing just after starting the engine that the SERV CODE icon is not visible on the panel..?

Another question. When the panel performs the self-test when the key is first turned on, does the SERV CODE icon appear at the RH side of the panel in the location shown in Mark's post #2 above..?

The brake pedal position sensor (it's not a potentiometer BTW, it's a PWM position sensor) and the microswitch that were replaced - were genuine Cat parts used and was the Power Train ECM calibrated afterwards...?

I'll ask again for the 3rd time. Please post the list of Codes registered in the Power Train ECM, logged or active it makes no difference. We need them in order to see what has generated codes in the past even though they might not be active now. I find it more than a little frustrating when someone posts here looking for help and then won't give a straight answer to questions that are trying to get information that ought to get us to the root of the problem..........

Last question for now. Would an Electrical Schematic for the machine help at all..? If yes PM me with an email address and I'll gladly send you the correct one for the machine.

Nige · Jan 23, 2016

After having slept on it I have another suggestion. Beg, borrow, or steal a Cat 4C-8195 Control Service Tool (aka Click Box). There is even information here on HEF how to build your own if need be. Then with the key on and the engine stopped erase every one of the Diagnostic Codes that are currently showing on the machine. If none of them are Active then they should all erase. Once all the Codes have been erased start the engine and observe what happens, I'm sure the machine will be no different. Once the engine has run, switch it off and then turn the key back on again and look for Diagnostic Codes. I have a few bucks in my back pocket that says there will be at least one and that Code will tell you where to start looking.

DPete · Jan 23, 2016

vegascowboy said:
Here is more info. Im sure this is getting complicated:

that there is no way to get past starting the engine. Once the engine starts up, the brake warning light and buzzer immediately sound, and keep the trans locked out. The diff-steer nor the brake release button beside it will affect anything. No way to operate the machine, other than the blade and ripper hydraulics. The lights work fine, the guages work fine, the engine runs fine. The machine was working in the bottom of a pond being constructed at the time when the brake suddenly locked down with the sound of the warning buzzer. It hasn't moved since. For almost 8 years now it has been periodically doing that in the middle of working. But always before, we could just pull up the park brake button beside the diff-steer and it would then reset and go. It got worse over the years, and had to be done several times a day[/B]. For a while it had been setting low voltage codes, and foot brake position switch codes, but then they would clear. I have talked with Cat numerous times and retrieved the codes and cross checked with our Cat service manual, and was never able to find a hard fault anywhere...only intermittant. I suspected a bad connection, ground, or wire or sensor or solenoid. I've been able to dertermine nothing all this time. But now that it is locked down and not resetting, so to speak, we still cannot find anything. So we replaced the foot brake position switch (potentiometer) and then the foot brake full stop micro switch to no avail...we even replaced the new position switch again in case it had been defective. Nothing. No codes, no bad readings so far.

Thanks

There is an access cover on the shift tower below the controls for the brake switch. The fact you could work the switch and get going is an indication of possible adjustment issues

bhtn · Jan 23, 2016

I'll post this just because our D5M was doing something VERY similar. Sincere apologies to Nige and the others on here who are very knowledgeable and willing to help. This was our farmer fix for our problem and got our machine back up and going. It's still going this way today because we have been unable to locate the actual problem and since it operates fine...... We do hope to get it in the shop one day and get this all sorted out. I also need to add that our machine is one with finger tip steering. Can't remember what that is properly called

Also I'll preface this with this....I don't know that your machine is even remotely the same as ours. Our machine would randomly lock down the brakes and not be able to move. Sometimes it would go back to operating in a minute and sometimes you would have to go home for the day and come back the next day and it was moving again and might run that way all day or several days and then do it again. We finally narrowed down our problem to one of the park brake solenoids. I don't remember what got us to that point but that's where we came across a solution. We felt like one of the solenoids was getting weak and letting the park brake apply when it shouldn't. In the process of diagnosing we unplugged one of the solenoids and found that the brake released. The CAT technician who worked on the machine for us once when it did this seemed to think it was a loose wire at one of these solenoids but we could never trace that down to that exact problem. At any rate unplugging the park brake solenoid stopped the problem and it has not returned. Our machine has two park brake solenoids (??) and it is just one of them that was causing the problem. Apologies if this isn't your problem. Also to all you guys that are so good on these machines please don't hammer me too hard for my farmer fix. I know it's not the right way.

Nige · Jan 23, 2016

The 2 solenoid valves on the manifold for the Park/Secondary brake dump manifold are identical, part number 133-2250. One gets its feed from the park brake switch via wire # G730 pink, the other gets its feed from the service brake pedal position switch via wire # G731 grey. The manifold assembly complete with the two solenoid valves is ref 16 in the illustration below.

Can anyone help with a D6R problem?

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