Cat 299C Park Brake won't release

Park Brake won't release when pushing the park brake switch. The diamond with ! flashes. The door, seat and armrest switches are working and the lift arms and bucket hydraulics will activate but the park brake won't release. I believe it is either the switch, the park brake solenoid, or the harness (no sign of damage to the harness). I removed the park brake solenoid and the resistance reads 7.3 ohms (don't know if that is within spec or not). I have purchased a new switch as it was not too pricey, but the park brake solenoid only comes with the hydraulic assembly to the tune of $300+ and is not returnable. I do not have the right side display, so I can't download error codes (think I may add that to the machine for future diagnostics). Appreciate any thoughts including whether the park brake solenoid resistance is within spec. Serial # is JSP02048

If you want to start checking wiring and need an electrical schematic please ask. Corrosion and/or damp in connectors is alway a possibility, especially on the electronic controls that are under the floor.

Cat299C said:

I removed the park brake solenoid and the resistance reads 7.3 ohms (don't know if that is within spec or not).

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Does it have a Part Number on it.?

EDIT: Scratch that. The complete valve is listed as a 278-8743 and the solenoid is not listed separately so there is no specification available for it.

Well, I installed the new park brake solenoid today and still have the same issue. When I start the machine, I have the yellow diamond with the ! inside flashing before I even press the park brake release switch. It’s either detecting an error at startup or there is an error code stored that needs to be cleared. Is there a way to reset the error codes? I disconnected the battery and will see in the morning if that did any good. Otherwise, I may have an issue somewhere in the harness or inside the ECU (which I hear is rare). Any other thoughts or ideas are welcome!

I think you may have joystick sensor issue. If the lever isn't indicating neutral to ECM, the park brake won't release, and the exclamation will flash.
I really don't think it's in the park brake circuit, your issue.

Okay, thanks for that! Would it likely do any good to wiggle the left joystick around? Anyway to test without Cat ET?

Does your monitor panel look like this.?

Nige, unfortunately I don’t have the right side monitor. I plan to order one today from the dealer. I have the service manual, but I understand that I need the monitor you show above to display the diagnostic codes. I guess I’m dead in the water until I get the display. Hopefully they can program it to my machine with me giving them the serial number as I have no way of loading it onto a trailer.

alpine740 said:

Nige, unfortunately I don’t have the right side monitor. I plan to order one today from the dealer. I have the service manual, but I understand that I need the monitor you show above to display the diagnostic codes. I guess I’m dead in the water until I get the display. Hopefully they can program it to my machine with me giving them the serial number as I have no way of loading it onto a trailer.

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You can buy the monitor alone but you also need a kit to install it. We had someone before who mistakenly bought just the monitor then found there was a lot more besides that was required. The machine ECM (not the monitor) has to be programmed i order to recognize the monitor panel, so the kit has to be installed first then hook ET up to it and do the necessary configuration.

There is a Special Instruction showing the required parts and the installation/configuration procedure. Let me try and find a copy of it. I'll post it up and you can see for yourself.

EDIT: The Kit I mentioned above is for D-Series machines but not C-Series. I can't remember if the C-Series has something similar, TBH the way I recalled it was that for both C & D-Series machines the kit & procedure was the same. Obviously that is not the case.

Right, the procedure for a C-Series is much simpler than a D-Series but still requires more than just the monitor panel. It also requires the Machine ECM configuration to be changed in order to recognize the panel after installation, and the latest available software has to be installed in the AMICS Monitor Panel itself. See attached, pages 8 & 9.

From the document I posted above........

The 264-8861 P/N AMICS Display Module has updated to 364-6336.
The latest software P/N for the AMICS is shown as 434-2352.
There is also a 363-8111 Group listed that comprises the 364-6336 AMICS with the 434-2352 software already flashed into it. Your dealer may or may not be able to get hold of that P/N.

Thought I'd share an update - I bought the optional display (part number 346-6336) that Nige referenced above and got it installed today. Turns out it was plug and play.
I was able to enter the service mode and have two active codes (2474-3 and 2476-3). Had a couple of logged codes as well (681-5, 70-3, 2685-8, and 2686-8). Working my way down the service modes, I noticed that the left joystick showed 100% when in neutral for both the X-axis and the Y-axis and it did not change when I moved the joystick. The right joystick showed 0% in neutral for both the X-axis and Y-axis. The percentages changed on the display for each axis when I moved the right joystick. I also noticed that the park brake switch stayed with a number 1 on the display and did not change when I depressed the switch. I believe that heymccall was correct when he indicated I likely had an issue with the left joystick. I have followed the wires from the speed sensors up under the belly and the wires under the left joystick and haven't found any signs of wear. Starting to think that I need a new left joystick base (456-0169) $500+. Any further thoughts / advice would be much appreciated!

2474-3 and 2476-3 both relate to the position sensors for the left joystick. Before condemning the base I suggest you try both these testing procedures and see where they get you.

Note: Unless all the position sensors are reading correctly (0% with the joysticks in neutral) the ECM will not permit the Park Brake switch to change status from 1 (On) to 0 (Off).

Cat299C said:

Had a couple of logged codes as well (681-5, 70-3, 2685-8, and 2686-8).

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Your Logged Codes are: -
681-5 - Parking Brake Solenoid, current below normal.
70-3 - Parking Brake Switch, both inputs open circuit. (The park brake switch is a 2-pole switch. At any given time one contact should be grounded and the other contact should be open circuit. The 70-3 Code comes up if the ECM detects that both contacts are open circuit at the same time.)
2685-8 & 2686-8 - LH drive motor speed sensors (#1 & #2) incorrect signal.

I forgot to mention it before. If you would like an electrical schematic to assist with your troubleshooting please ask.

Nige, thanks for that; I actually have the electrical schematic. Looking at it, the power circuit (126-CH24 PK-16) feeding the left joystick goes from fuse #9 thru connector #23. I can't find where connector #23 is located as it doesn't come up on the machine location diagram. Any help here much appreciated!
The signal wire circuits (E848-C158 GN-18) and (E847-C157 GY-18) terminate on connector J2 at the ECU (pins 33 & 34 respectively). I see two large connector blocks bolted to the ECU but can't tell which one is J1 and which one is J2. Presumably, I will be able to read the pin numbers once I unbolt the connector from the ECU? Any help here also much appreciated!

Cat299C said:

I actually have the electrical schematic. Looking at it, the power circuit (126-CH24 PK-16) feeding the left joystick goes from fuse #9 thru connector #23. I can't find where connector #23 is located as it doesn't come up on the machine location diagram. Any help here much appreciated!

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I must have a later schematic than you then because it shows up on mine. I'll send you a copy, keep an eye on your PMs.

TBH ECMs can be installed oriented in all sorts of ways so I always identify J1 & J2 from the electrical schematic working from wire colours and numbers. The pin numbers are actually on the outside of the harness connector but are very small and if you don't look closely they are easy to miss. Below is a 12-pin connector to give you an idea where they are, right next to where the wires go into the connector.

It looks like you may have already found a culprit in your joystick, but just in case you didn't see this thread, I had a similar issue with the same machine. Long story short, it was the parking brake switch. I performed surgery on it and cleaned up the contacts and it has been working ever since. Not suggesting this is also the cause of your issue, but just know these switches tend to corrode over time. I also had a similar issue with my quick attach release switch. Fixed it the same way.
https://www.heavyequipmentforums.com/threads/cat-299c-parking-brake-stuck.93704/#post-1035326

Thought I share an update - the Cat is working again! Thanks for the help getting this one figured out! I installed a new left joystick base today, plugged it in and started it up. The machine ran like new again. I had read where I may need to get the new joystick base calibrated, but I did not.

I know this post is almost a year old, but would like to thank Nige for posting the information on the display. I have a 287C, without the 2 speed, and without the display, and know that the display and gauges are a very useful item to have in the machine. Ill likely order the install kit and hopefully mine is plug and play so I dont have to have someone with ET program it!