Afternoon gentlemen have a 670 J Dozer have no throttle response I have codes have 3 codes the first code I have is F9C3 I looked it up and it says mdv not receiving message from the transmission TCM 2nd code F423 Transmission control is not receiving a signal 3rd code F9C4 no communication from the ECM The numbers on the ECM part number it's RE522527 S/N 124197 I found your site and I just figured I'd shoot it out here and see if anybody has any ideas would be appreciated I'm going to contact the dealer but I figured I'd try this first thank you guys for some upstate New York
670j I don't believe is a good number for a dozer. I may can get some codes but need the right machine...
This sounds reminiscent of a ECM failure due to contamination we had on a 450j dozer, check around the ECM case for corrosion near the main harness plug... if you see it then there is a pretty good chance the main board on the ECM has been compromised and is throwing false codes and other issues.
Thank you for the response that's what I was leaning towards also cuz you disconnect the battery and clear the codes it will move for about a minute in the codes come back again and that's it it's totally won't move
F9C3 and F9C4 are codes for the display controller (MDU) not receiving CAN communications from the TCU and ECU controllers. F423 is for the ECU not receving a thrttle message from the TCU over the CAN bus. Sounds like you have an issue with your CAN bus, might need to check for a damaged harness somewhere on the machine. There are two 120 ohm resistor plugs on the machine, if these are bad could cause CAN issues. One is on right side of the engine by the ECU and the other is back left of the cab by the TCU. Check the resistance of the green and yellow wires in the 9 pin connector by the TCU, back left inside the cab. Should be 60ish ohms with the machine turned off.
Hi just ran across this thread, had to join. I have a 2006 450j lgp with the codes f423 and f9c3, was running fine made 2 pushes, stopped idled down and that's when the codes appeared. Any help would be appreciated.
Mestizo already presented the trouble shooting tree above. Basically the codes tell you the the dash MCU and TCU are not online. That means that you have no power to the module or you have CAN (data cable) failure. Check the fuse first. Then check for wiring harness damage or a loose or corroded plug connector.
And from what I've hear with other machines of similar age to the couple I looked at with the corrosion issues at first we thought it was bad connections/faulty sensors/main ground/etc.... but once I determined the problem with with the main ECU I cracked it and found the real problem due to a bad design/faulty powder coating on the main computer enclosure corrosion starts and continues until it starts affecting the i/o connections and anything else it want to play with... Do the regular troubleshooting first like partsandservice says but if you start going in circles with things just not adding up and then other codes start popping up don't be surprised if it isn't just a bad connection or sensor...... here are some pics of the first dozer ecu I opened up.
Follow Mestizo's advice. If the "CAN" ohms's checks out then you may want to check your harness. Those machines with a cab (if you have a cab?) like to wear out the cab mounts and the cab sits lower on the frame pinching the harness under the floor board on the left side in front of the TCU and in the front 2 corners. Also in the area in front of the TCU inside the side compartment. If that TCU looses power or ground even for a fraction of a second it will shut down.