Code 636-2 engine position sensor, data erratic, intermittent or incorrect & code 636-8 engine position sensor, abnormal frequency, pulse width or period. I already changed both of the sensors, tried a different computer from another 259D machine & nothing seems to work. One thing I found is that there’s a 5 volt wire that comes from the ECM to the sensor & is not working when is plugged to the ECM, I already tested the cable by itself & it looks like it does work. So I’m trying to figure out what or which cable supplies the power to the ECM that supplies the power to that 5 volt wire. So all I know is that the machine started losing power & going into limp mode & it was driving rough. Serial no: 8DW2282 one of the cat representative couldn’t find it with the serial no so here’s the last 8 digit of the vin FTL0030
That's only 7. It's missing a digit after the FTL. The last 8 of the 17-character PIN is the machine Serial Number. Regarding electrical schematics there are three different S/N groups of the FTL machine, so it's important to know which group your machine fall into.
My fault is FTL00930
No worries. FTL00930 will get you everything you need in the way of parts & service information. Keep an eye on your messages. Electrical schematic on the way.
Copied and pasted from another thread regarding 636-2/636-8 Diagnostic Codes. © - @Cmark "I'm not usually one to advocate for taking short-cuts where troubleshooting is concerned, but look in the circled area below. You should find the harness zip tied to a ladder clip bolted to the chassis. Look for harness damage in this area. It MAY save you some time. Good luck."
I appreciate it boss, I got another question in the electrical schematic I see the Sensor- CAM shaft & sensor- crankshaft angle & I see where they go to in the machine but where exactly those wires come from? They are 77 & 79 in the machine location & F-13 in the schematic location but I don’t see F-13 in the schematic location or any connector for F-13
The wires to the crank and cam sensors go to the engine ECM. F-13/E-13 etc, are grid references on the schematic. You can find the grid on the outside edges of the pages that contain schematics. The schematic is searchable so if you put in one of the wire numbers (e.g. 997 for the crank angle sensor or F732 for the cam sensor) you can follow them all the way back to the engine ECM located in Grid E-16 of Page 9.
The 5 volt reference is usually what the ECM is looking at as to how sensor is working, if it has 5 volts unplugged, but disappears when plugged in, to me would indicate the 5v has been pulled to ground, either bad sensor, which you changed or shorted ground wire. Something to check anyway.
It could be pull-up voltage but I think it depends where he's measuring. The cam & crank sensors are both powered by 5v from the ECM.
True enough, they should share the same 5v reference, but I guess there could be more than one. A scope hooked to both, and some wire wiggling might show something
I sent him the electrical schematic. Let’s see what he comes back with. The inspection of the engine wiring harness for damage as indicated by Cmark really ought to be the first priority. The +5v supply and ground for each of those two sensors come from different pairs of pins on the ECM. So nothing is common between the two.
Did anyone find out any thing with this problem? This is the exact same things I'm going through. I was going to ask for help on this. But I don't think I could say anything different. Except what is the 1150 Ω Resistor? My machine FTL03241.
What Active Codes do you have and what are the machine symptoms.? I don't see any reference to a resistor on the thread above. Where did you get that from.?
Im have the same problem it will start but hard it's in limp mode I have a 636-2, 636-8, and a 3509-4 codes I have 5v to all the sensor except to crankshaft. The resistor part cam from caterpillar Sis2go app
All Active.?
Both 636 codes i erased and they have not came back
So all you have Active right now is the 3509-4, correct.? I’m just trying to get to the bottom of what you have Active right now in order to figure out a way forward. Did you inspect the common harness fretting location shown in the illustration along with Post #5 above.?
Yes 3509-4 is the only thing active right now I have checked the wiring harness. I have seen nothing I just pulled the resistor out and checked that and it's good I'm about ready to just pull all the wiring harness out to see if Im missing something.
It may pay you to clip the zip tie fixing the harness to the ladder clip in the circled location and take a peek at the condition of the harness directly under it. The pressure of the zip tie is what results in the parting of a wire or wires in the harness at that spot. The procedure that you took the snip from above is from the speed/timing system test. This is used when there are Active 636 and/or 723 Diagnostic Codes of whatever flavour. But you don't have any of those, at least not at this time. All you have is the 3509-4. Therefore you should move to the Sensor Power Supply Test procedure attached below. Post back with any questions you may have.
I know this post is old however still relevant for my current issue, I have the 636-2 code as active i replaced both cam and crank sensors per the recommendation of the cat tech who brought his computer out for a diag on the machine, when I replaced them it ran fine for about a week and now its back in for the same issue. I tested the ground to verify its grounded properly and it tests good, I test the +5 volt supply which it has, I tested signal wire, and it also has +5 volt. from the diagram I have it does not reference anything about voltage on the signal wire side. I left the sensors plugged in to prevent pull up voltage. cam sensor has the +5 volts at the supply side but nothing at the signal side. so, I'm thinking the crank sensor has died after 1 week. any help would be great the last 8 is CW924832. any help would be great.
I'll not comment on that......... Do you still have a Active 636-2 Diagnostic Code.? Any other Active Codes.?
Just the 636-2 is the only active code.
First step. Go back to Post #5 on Page 1 and check the wiring harness for damage in the indicated area.
If you want to perform a continuity test for the engine speed sensor signal wire between the sensor and the ECM I would suggest the following is a more reliable way of testing that a simple resistance measurement of the wire from one end to the other. I have seen wires ohm out at close to zero yet be almost cut right through. Unplug the harness connectors at both ends of the wire you want to test. In your case that would be at the engine speed sensor and at the engine ECM connector. Connect one end of the wire to machine frame ground. Connect one terminal of a 60W (5A) bulb to the other end of the wire. Supply the terminal on the other side of the bulb with battery + voltage. If any wire will carry 5A of current and not go pop I’d call it good.
Checked all wiring for both crankshaft and camshaft sensors they all tested good, I then isolated them via pin out to check Ohms while shaking and bending the wires and no change in resistance. Is there something else I should check?
I would not consider the crankshaft sensor signal wire to be guaranteed good until it had been subjected to and passed a 5A load test (see Post #24 above), but that’s just me.
I preformed the test as described in post #24 let the light run for 3 minutes for each wire while having them isolated from the ecu. light stayed on no smoking wires no flickering while jiggling of the wires. so im now thinking the sensor that was replaced last week is now bad
I think you're right. You appear to have exhausted all the other possiblities. Were the new sensors that you bought OEM or aftermarket.?
OEM from our local Cat dealer
Parts warranty in that case........... As someone said the other day "New simply means not tested in operation yet". It's a condition known in the trade as infant mortality.
yeah I know just because it says its new dont mean anything at all
Thank you for the help and advice. I apricate it
Hi Nige Do you have a diagram on where the camshaft and crankshaft sensors are located on the cat 259d? Serial number for this one is FTL16166 Thank you I had some codes come up for the dpf filter. E1239-3. This code went away after resetting the soot and regeneration levels. I did the reset right before I took out the dpf 636-2 636-8 These were all displaying before I took out the dpf. Then I took the dpf out, had it cleaned at peterbilt because caterpillar didn't do it and recommended them. Reinstalled the dpf. The only active diagnostic code right now is 636-8 the machine starts. Moves around so far so good. The start up feels a little heavy but after it starts seems fine. I have not ran it hard yet. But was wondering if I should worry about the code Thanks
I would worry about anything related to crankshaft or camshaft sensor Codes. The engine will run if one of the two sensors is on the blink, but if the other one happens to fail it becomes a beached whale. See the illustration below. The crankshaft sensor is #16, the camshaft sensor is #2.
I have thought of one more possibility but it is too terrible to even contemplate - a bad engine ECM....... It is a Kubota part not Cat and they have "previous form" for doing weird things. It's not unknown but a very remote possibility.
yeah it could be however from your above diagram number 16 being the cam sensor also means I've been testing the wrong part. The dealer said number 2 was Crankshaft sensor and 16 was cam :facepalm:
Thanks Nige Are these two sensors same?
I should of also mentioned that there is a longer than usual crank on starting the machine
I have just looked again to double check. Attached the parts list so you can see for yourself. Crankshaft sensor is definitely listed as #16 - unless of course the diagram in the parts listing is labelled wrong. I always recommend confirming sensor identification by comparing the wire colours and numbers on the electrical schematic with what is physically on the machine. Also attached the R&I procedures for both sensors that may assist in confirming the locations. The same parts lsting works for your engine. As you can see the Part Numbers for the two sensors are not the same. Classic symptoms of a misbehaving sensor. 636-8 - Engine Position Sensor. Abnormal Frequency, Pulse Width, or Period. Battery voltage is normal. Sensor supply is normal. Engine is not stalled. Pulse count per rotation is not 56 teeth occurs 10 times or more. No recognition of crankshaft for ten times or more. Engine is derated. Warning Level 2. Symptoms are long engine crank before starting and possible increased engine vibration. Engine will stop if both crankshaft and camshaft position sensors fail.
Thanks Nige Do you have the wiring schematics that goes from these sensors to the ecm?
Thank you I will begin my testing all over again due to the mix-up maybe I'll find the issue Afterall
I do. On its way to your message inbox. You will need to perform the Speed/Timing Test (attached).
Thank you very much Nige I'll see what happens from here and keep you all posted
More confirmation, if any were required, regarding the respective locations of the two sensors.
Nige, can I also have the schematic for the sensors to the ECU please and thank you.
Certainly. Check your message inbox.
Hi Nige I was just testing the voltage on the crankshaft position sensor. There is 3 wires One is ground One is giving 5volts And the other one is giving 0.51xxx volts whether I rev the machine or keep it on low I was wondering if the 3rd wire signal needs to change with the change of revs rpms?
AFAIK that is the pull-up voltage generated in the ECM for the diagnostics of the signal wire. It is not the signal itself. If the signal from the sensor is PWM then you need a multimeter capable of measuring duty cycle. If it is Hall Effect you might need a scope. TBH I’m not sure what type it is, maybe someone else knows.
Thanks Nige I was reading in one of the documents you sent me that it could be a faulty 1150 resistor. It was saying to look at the "Electronic System Overview" for the location of the resistor? Do you have that by any chance
There are hyperlinks all over the schematic. Click the one next to the resistor, it should take you to an illustration showing the location.
Also you can test the resistor without having to physically find it by measuring the ohms across the two wires it is connected to. If it is bad it will measure something different to the 1150 ohm spec.
I'm assuming that's if I can find the wires that go to the ECM. I did find it and the resistor does measure 1150 ohms. I'm trying to find the wires that go from the crankshaft sensor to the ecm. Regarding the hyperlinks, do I need a special computer or software to get them to show? Thanks again Nige
See page 1 of the schematic. They call it hypertext. So if you find the resistor location on the schematic and want to find the location on the machine, just click on the blue hyperlinked text and it wil ltake you to this illustration.
The crankshaft sensor costs $300 and the o ring is $20 so before I buy it i just wanted to confirm if it's actually the sensor The camshaft sensor and the crankshaft sensor are not identical so I can't swapp them When I took out the camshaft sensor the machine turned over but did not run. When I put it back it starts. So I know the camshaft sensor is fine so it seems like the machine is depending on the secondary sensor which is the camshaft one. The resistor it's self is good but I'll have to check the actual wires going to the ecm. And I guess the last thing I'll do also is check the wires from crankshaft sensor to ecm and if they seem fine then it's probably the sensor. Again thanks Nige
Put the 3 or 4-digit wire number (997, 993, etc) from one of the crankshaft position (angle) sensor wires into the Adobe Acrobat search box and click search. It will find every instance of that number that is on the drawing.
Nige again thanks I been doing that on my phone lol But I thought there is hyperlinks that actually find the location Anyways I appreciate all your help it was very useful and if there is anyway to repay you for your kind help please let me know
so Nige, I had the weekend to mow over everything you have helped with and after retesting the proper sensor i have the same exact results as the camshaft sensor, 5amp load move wires no flickering or anything, I preformed and Ohms test on it as well and it holds steady at .5 ohms, i tested the resistor and it test good at 1150 ohms. i can only assume the sensor has died for some reason ive exhausted everything else and still has my head hurting. what do you think?
Hi For me it was the plug for the sensor As I was testing continuity from the 3 wires to the ecm
ill look into replaceing the plug as well as the sensor. thank you for the help.
My plug seems to be fine but I will feel better if I just replace it to eliminate the possibility of it being faulty.
The only way the connector (plug) can be faulty is if the plastic retaining clip is broken and the two halves of the connector are not being securely held together.
Hi Nige I should of been more clearer. Sorry about that. The connector itself was fine but right where the wires connect, one of them was broken but I was not able to splice that wire because I couldn't take out the wire from the connector. So I had to get a new connector.
i was informed that i would nice a splice harness to replace that connector, they are going to warrenty the part and if that dont fix it then thats what ill have to do as i have to get approval for the purchase beforehand.
Which connector exactly are you talking about.? A machine location and a photo might help.
left side machine, crankshaft sensor harness plug, ill try to get a picture today.
Sensor replaced and now seems to be fine, I will know after it goes out in the field to go back to work. If it does it again, I'll be doing the connector/ splice harness as that will be the last step in this repair process being that i have tested all other avenues minus the ecm.
Are you talking about the half of the connector that is part of the machine harness.? EDIT: If you are then there is a Part Number 419-0084 for just the connector. This is according to the schematic. What brand of connector it is will only be revealed with a photo. It may also require special tools to disassemble/assemble.
Thank you Nige, Yes cat said they have a split harness to repair the connector, im assuming its a cut and solder style harness as the price is like $35.00
update, since installing the new Crank sensor machine seems to run fine and has been out in the field since the repair was completed. thanks again for the help Nige
another update, machine returned with the 636-2 again and it is now displaying a 3509-4 serial number is CW924832, any additional help would be greatly appreciated, I'm leaning towards replacing the harness at this point
3509-4. Sensor power supply #1, voltage below normal. See the attachment. Get that one sorted and see what effect it has, or not as the case may be, on the 636-2.
hello, new here. could you show me where this resistor is located please? i already replaces the position sensor and i still get this code.
You need to upload the schematic to a PC in order for the hyperlinks to work. They apparently don’t work on a phone or a tablet. As I said earlier, click the hyperlink and it takes you to an illustration of the machine showing the physical location.