Cat 299D - 723-8 Error Code - Engine position Sensor - Abnormal Frequency - Pulse Width or Period

My 299D2 XHP was throwing code 723-2 and would run for awhile and then the parking brake would come on, bringing machine to a hault. I would turn the key off and then back on and it would run for about 15 -30 minutes and then parking brake would come on again. Got around to switching the (2) sensors to determine if I had a bad camshaft sensor and then it threw a code 723-8. Ran it for about 15 minutes and then my fuel pump went out. Replaced fuel pump, started the machine up and now the parking brake won't release and I'm still throwing code 723-8. Decided to switch the (2) sensors back to the original position and after doing that, I'm still throwing code 723-8 and parking brake won't release. My machine is down and wont move.

Before I dive into this and check the wiring and connections to all cam sensors... (Question) is this normal that the parking brake won't release when throwing the code 723-8? I suspect I have a lose connection or a broken wire on (1 or 2) of the connectors at the engine block?

Do you think I have (2) separate issues are is the parking brake (not releasing) caused by the code 723-8


Model - 2018 Cat 299D2 XHP
SERIAL NUMBER: DX203342

Note: I had the same issues with the code 723-2 and 723-8 being throw last year, and my fuel pump went out. I changed the fuel pump and did'nt have any issues with it for 8 months until this started. (NOTE: I purchased a china pump on ebay to replace the old pump last year, and when the china pump went out I went ahead and purchased a new cat pump.

Any help would be appreciated. Thanks!

See this thread. Same 723-8 Code (amongst others) and the test procedure is also there.

Any electrical connector you pull apart I would suggest that you give both halves a good cleaning with aerosol contact cleaner before reconnecting.

Nigel,

Thanks for your quick response
We are in the process of running test and checking connection

While doing this, the engine now wont start. Its a hard start. Would this cause the engine not to start.

Thanks!

uglyguy said:

While doing this, the engine now wont start. Its a hard start. Would this cause the engine not to start.

Click to expand...

Possibly. I would suggest to see if anything changes after doing all the tests.

Unplug that sensor, should start just fine on one sensor. Will crank a bit longer before it fires. Then also try it vice versa

Ozarkag,

(Still no Start) here is what I've tried so far.

1) Unplugged each sensoe (1) at a time.
2) Changed Fuel Filter
3) Verified we are getting fuel to engine by unhooking fuel line to engine to see if pump was pumping to engine. Plenty of fuel flow to engine.

My Issues
- Engine wont start - Hard Start
- Parking Brake will not release (When it did start and engine running)
- Throwing code ---723-8 Error Code - Engine position Sensor - Abnormal Frequency - Pulse Width or Period

What did the troubleshooting procedure for the 723-8 Code indicate.?

Nigel,

1) Can you please provide me a electrical schematic for my 299. I'm looking for the 1150Q Resistor on the engine harness.

2) I'm in the process of performing continuity checks on the Cam and Crank Sensors.
- Going to unplug the sensor on the harness side and measure the voltage between pin 1 and 2 with the key turned on? Make sure to check if there is a reading of 5V. (Pink/Grey and Orange wire at the sensor harness plug.should read 5v with key on)

uglyguy said:

Can you please provide me a electrical schematic for my 299.

Click to expand...

Certainly can. Check your messages.

I would like to order new plugs for the Sensors. Plug is marked PBT. Any suggestions on where to find and order them? Tried Ebay, but it came up many different plugs.

Nigel,
Thanks again for your help.
1) Tested Resister 119.5 (Appears Good)
2) Tested Cam Shaft Sensor 5.0 (appears fine) but inspected wires and found (2) wires broken). Solder all (2) wires and reconnected. Engine started up (sputtered for a bit) and runs. Parking brake still will not release. Now throwing a new code 636-8 Engine Position Sensor Abnormal Width & Period.
3) I would like to order new plugs for the Sensors. Plug is marked PBT. Any suggestions on where to find and order them? Tried Ebay, but it came up many different plugs.

uglyguy said:

636-8 Engine Position Sensor Abnormal Width & Period.

Click to expand...

That's the other sensor, the upper one that senses camshaft speed. See attached. 636 & 723 Codes use the same diagnostic procedure.

Question: When you removed the lower sensor to inspect did it have one or more shims (marked #3, 4, & 5) on it.?

uglyguy said:

I would like to order new plugs for the Sensors. Plug is marked PBT.

Click to expand...

Is that a Kubota engine.? I'm not sure what brand of connectors they use. Hopefully someone else knows but to further aid identification take a photo looking directly at the connector rather than from side-on.

EDIT: The Cat Part Number is 371-0502 but they are likely to be expensive if they even sell them. I can't see it listed anywhere.

TBH I would finish your diagnostics first because if the worst comes to the worst you might be in for a replacement engine wiring harness.

Nige said:

Is that a Kubota engine.? I'm not sure what brand of connectors they use. Hopefully someone else knows but to further aid identification take a photo looking directly at the connector rather than from side-on.

EDIT: The Cat Part Number is 371-0502 but they are likely to be expensive if they even sell them. I can't see it listed anywhere.

TBH I would finish your diagnostics first because if the worst comes to the worst you might be in for a replacement engine wiring harness.

Click to expand...

Yes, it is a Cat C3.8 engine / Kubota V3800-CR engine​

In that case someone will have to help you on the brand of connector Kubota uses, because the one in your photo is not the Deutsch DT style that Cat uses on the rest of the machine.

Just a shot in the darkl, but even though it says alternator on the description is this it.? Sit down when you look at the price.......

Nige said:

That's the other sensor, the upper one that senses camshaft speed. See attached. 636 & 723 Codes use the same diagnostic procedure.

Question: When you removed the lower sensor to inspect did it have one or more shims (marked #3, 4, & 5) on it.?

Click to expand...

Nigel,
We just removed both sensors and switched the (2) cam and crank sensors. When we did this, the engine would not turn over, so we switched them back again and the engine starts, but parking brake, still will not release and the RPM Gauge on the monitor shows (FAULT)

Nige said:

Question: When you removed the lower sensor to inspect did it have one or more shims (marked #3, 4, & 5) on it.?

Click to expand...

The 3 different shims (.010", .020", & .040" thickness) are called out "as required" so no surprise there. I just wanted to check iif there was at least one in there.

uglyguy said:

We just removed both sensors and switched the (2) cam and crank sensors. When we did this, the engine would not turn over, so we switched them back again and the engine starts ....... and the RPM Gauge on the monitor shows (FAULT)

Click to expand...

You can't swap those sensors willy nilly like that without re-shimming the clearance on the replacement one you install on the crankshaft. It might need more or less shims, but it is highly unlikely to work "as-is".

I don't think that the fact the park brake is not releasing has anything to do with the engine Speed Sensor faults. If the engine starts and runs and is getting a good signal from at least one sensor it should be happy. It will however still show the other sensor as "faulted". I can't recall which of the two sensors provides the RPM signal to the dash display. That will be done inside the engine ECM.

What Active Codes do you have now.?

1) Code- 636-8 "Engine Position Sensor Abnormal Width & Period" shows up on may screen, but when I go to the active codes screen, nothing is showing up
2) RPM Gauge shows "Fault" and does not read anything
3) Parking Brake will not release. - Engine Starts, but can't move machine, because parking brake is on.