CAT 299D won't move

[Jeffrey Bandel]

I was poking around on the passenger side and found this"connection" from the speed sensor. It was wrapped in electrical tape. Looks like someone worked on it. I'll fix it correctly. The other side has what I'll call "flexible protective conduit" around the wires. It is braided and hefty. Does anyone know what it is called or where I can get it?

 

[Nige]

You mean this stuff..? It's factory original but not sold separately to a harness AFAIK under its own Part Number. No idea where you might get it.

To "fix" that harness break correctly you have to remember that the signals from the speed sensors are of the PWM variety and not very tolerant of high-resistance crimped connections.
Look up Cat P/N's 115-8109, 8T-8729, & 8T-8730. You'd need four of each, plus get hold of a good crimp tool to crimp the pins on to the wires. Probably about $20 the lot for the parts.

Just thinking there was another thread about someone who was having trouble with speed sensor wiring on a 299D. Maybe you should consider that upgrade also..? https://www.heavyequipmentforums.com/threads/cat-299d-skid-steer-speed-sensors.78067/

 

[Nige]

The harness protection kit is Part Number 485-4342. No idea of price. Installation instructions attached.

 

[Jeffrey Bandel]

I fixed two breaks in the harness. It didn't solve the problem.

 

[Nige]

Looks like you’re back into the troubleshooting procedures in the previous page.

 

[Nige]

Just a thought. Did you move the machine after repairing the harness..?
The reason I ask is, like most speed sensor issues, the ECM keeps the Diagnostic Code "active" until it receives a "good" signal from the sensor. You can fix the breaks in the wires but unless you move the machine and give the ECM chance to receive a good signal the Diagnostic Code will not change from Active to Logged. Once it is Logged the symptoms ought to go away - if indeed it was a fault with that sensor that caused the problem in the first place.

 

[Jeffrey Bandel]

I moved it twice. I got about 15 feet worth of movement before the parking brake locked it up each time

 

[Nige]

Back to going through the troubleshooting procedures from Post #38 then, I would have thought to start with the two sensors on the LH side since that's where you found the damaged wiring.
I hope you have a digital multimeter, you'll need one.

 

[Jeffrey Bandel]

It sure would be nice to know the codes to narrow down my efforts. It won't help me now, but someone mentioned earlier about upgrading to a diagnostic module. Is this possible and is there an estimated cost?

 

[Nige]

If you look at the procedure for both FMI02 & FMI08 it is the same. Therefore you only have to perform one test on each side of the machine.

Regarding upgrading to the Diagnostic Module, refer to post #31 on Page 2. Cost about $1000. Be aware that it's not plug & play, it has to be configured using ET.

 

[Jeffrey Bandel]

Even if I get it fixed I will probably have to take it to the dealer to have the DPF serviced. That seems like a good time to get it installed.

 

[heymccall]

If you're gonna consider the diagnostic display, inquire about adding the tear camera, too.

 

[Jeffrey Bandel]

I worked on the machine yesterday. The left side was not getting 8volts. I found a break in the harness on the left side. That didn't fix the problem either. It moved about 15 feet and then locked up again. Now the parking brake is locked in. It doesn't matter what I do, I cannot turn it off.

I have a question on the service manual relative to testing the motor speed sensor. When testing the harness it says "Measure the voltage from Yellow and White". It should be 8V. On both sides I get 7.9 volts on the yellow wire and nothing on the white wire. It looks like the white wire is an 8V return, so it shouldn't test out with voltage when unplugged???

 

[Nige]

You're not checking the correct way.
With the sensor unplugged and the key on you should have the +ve lead of the DMM on the yellow (+8V from ECM) wire and the -ve lead of the DMM on the white (ECM return) wire. It is that circuit you are testing, not 8v to frame ground.

 

[Jeffrey Bandel]

That's the circuit I'm testing. Here is exactly what the manual says "At the machine harness for the sensor, measure the voltage. Measure the voltage from contact 1 (wire P769-YL (Yellow)) AND contact 2 (wire P770-WH(White))."

I read this as ground the multimeter and then test voltage from the yellow and white. Are you saying the AND from the instructions should read to?

 

[Nige]

Yes indeedy. Maybe the text is not 100% clear but if you consider the mini-schematic at the start of the procedure it makes perfect sense. The 8V+ supply from the ECM is not shown as returning via machine frame ground - it returns back to the ECM via wire P770 White to complete the circuit.
Maybe this sketch will help. It shows the sensor disconnected. Red & Black are the + & - cables of your DMM.



The for the next step in the Procedure install a jumper between pin #3 & Pin #4 on the sensor connector. Then disconnect Connector J2 at the machine ECM and do a continuity test from Pin #29 on connector J2 through the harness via your jumper and back to Pin #37.

 

[Jeffrey Bandel]

I retested and have 7.9volts on both sides.
Now I'm looking at the J1 and J2 connectors. How do they come off? Remove the screws?

 

[Nige]

Yes. Each connector requires a 4mm Allen Key if I'm not mistaken. The screws are captive in the connector, as you unscrew them the connector will separate from the ECM.
Give everything a good clean with aerosol electrical contact cleaner while you're in there.

 

[Jeffrey Bandel]

Thanks. Back home to get more tools.

 

[Jeffrey Bandel]

Are the pins numbered once I get it off?