450J Speed Control Not Working, Dozer won't move

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TexasFarmer1984
MC crawler
MC crawler
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Joined: Mon Jun 18, 2018 8:32 pm

450J Speed Control Not Working, Dozer won't move

Post by TexasFarmer1984 » Fri Aug 03, 2018 12:19 pm

The engine cranks fine but after I try to turn the speed control knob, the engine will not speed up and won't move. The knob solenoid is receiving voltage and the resistance does change when the knob is turned. Does anyone know what's causing this?

TexasFarmer1984
MC crawler
MC crawler
Posts: 4
Joined: Mon Jun 18, 2018 8:32 pm

Re: 450J Speed Control Not Working, Dozer won't move

Post by TexasFarmer1984 » Tue Aug 07, 2018 12:16 pm

I've got it to work but don't think it's a permanent solution. To get it out of idle, I would spam the "next" button on the TCU while moving the parking break up and down every so often until I hear the engine rev up.

All of the breakers and Relays worked fine. I cleaned out the two 120 ohm resistor plugs by the TCU and ECU. I also cleaned out the 10A breaker by the ECU.

The three error codes I have (and still have) are F9C3, F9C4, and F423.

From my research, I THINK (i'm not an expert):
F9C3 + F9C4 are codes that the display controller is not receiving Controller Area Network (CAN bus) signal from one or both of the TCU + ECU.

F423 are codes for ECU not receiving throttle messages from the TCU. I THINK the ECU would receive signal from the TCU via CAN bus.

My best guess is that the TCU is going bad.

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Rincon
420 crawler
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Location: Las Vegas , NM

Re: 450J Speed Control Not Working, Dozer won't move

Post by Rincon » Tue Aug 07, 2018 1:19 pm

Did you disconnect and reconnect battery after a day or so, clear the codes. and see if the same ones come back.

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