Bobcat M7504 (75-04) Fault Code: Drive Controller No Communication
Also shown on the panel as 75-04 · Also called Drive No Communication
Drive Controller No Communication · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M7504 (panel code 75-04) sets when Bobcat's gateway controller loses CAN communication with the drive or drive plus controller. It shows up on S510-S770 and T550-T870 skid steers and track loaders whenever the key switch is on and PTOL is enabled. It's a communication fault, not a direct drive-motor failure, but the machine's drive system depends on this link to function correctly.
High severity. This code means the machine's gateway and drive controllers can't talk to each other. Depending on how the loss of communication affects drive response, this can range from an annoying warning to a machine that won't move correctly. Treat it as a stop-and-diagnose issue before operating in any situation where unexpected loss of drive control would be dangerous.
What does Bobcat error code M7504 mean?
M7504, also shown as panel code 75-04 and described as 'Drive Controller No Communication' or 'Drive No Communication,' means the gateway controller cannot establish or maintain CAN communication with the drive/drive plus controller. These two controllers talk to each other over a CAN bus, and the drive controller relies on that communication to properly manage machine travel functions.
This is a network fault rather than a sensor-reading fault. The gateway controller isn't complaining about a bad signal value, it's saying the drive controller is silent on the CAN bus entirely, or intermittently silent. That can be caused by wiring problems in the CAN lines themselves, power or ground problems feeding either controller, or a controller that has failed or lost power.
Because drive functions are safety-critical, any loss of communication between these two controllers should be treated seriously, even if the machine still seems to move. Confirm normal drive response before returning the machine to full duty.
Common causes of M7504
- CAN communication wires open: labeled as wires 91xx or 92xx on some models, or wires 9530 or 9630 on others, depending on the specific machine and controller variant.
- Supply wires 1250 or 1260 open, cutting power feed to the gateway or drive/drive plus controller.
- Ground wires 2470 or 2490 open, breaking the ground return path for one or both controllers.
- A failed gateway controller.
- A failed drive/drive plus controller.
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, drive/drive plus controller connectors, the AWS/SJC harness, or the mainframe harness.
- An intermittent condition: if the code is not active at the time of testing, the root cause may not be found immediately. Probable causes for intermittent faults include loose connections, corrosion, pushed-back pins, a marginal controller, a wire harness issue, or some combination of these.
How to troubleshoot Bobcat M7504: first checks
- Confirm the key switch is in the run/enter position and that PTOL is enabled, since these are the two conditions required for the code to set. If either condition isn't met, the code behavior may differ.
- Inspect the gateway controller and drive/drive plus controller connectors for moisture, corrosion, or pins that have been pushed back out of their normal seated position.
- Check the AWS/SJC harness and mainframe harness connectors along the CAN communication path for the same moisture, corrosion, or pushed-back pin issues.
- Test the CAN communication wires (91xx/92xx or 9530/9630, depending on the machine) for continuity and confirm they are not open or shorted.
- Test supply wires 1250 and 1260 for proper voltage feed to both controllers.
- Test ground wires 2470 and 2490 for a solid ground path, since an open ground can mimic a communication failure.
- If the code is not active during testing, treat it as intermittent and focus on connections, corrosion, and harness condition rather than assuming a single component has failed.
How the code clears
Once the repair is complete, cycle the key power off and back on. No separate clearing step is listed beyond cycling power.
Affected models and serial ranges
M7504 appears in our records across 16 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-ATZC99999 |
| S530 | SN A7TV11001-99999, SN ATZD11001-99999 |
| S550 | SN A3NK11001-A3NL99999, SN A3NM11001-99999 |
| S570 | SN A7U711001-799999, SN A7U811001-899999 |
| S590 | SN ANMN11001-99999, SN ANMP11001-99999 |
| S630 | SN A3NT12370-99999, SN A3NU11001-11111, SN A3NU11112-99999 |
| S650 | SN A3NV11001-13098, SN A3NV13099-99999, SN A3NW11001-11248, SN A3NW11249-99999 |
| S750 | SN A3P211001-299999 |
| S770 | SN A3P411001-99999 |
| T550 | SN A7UJ11001-AJZV12276 |
| T590 | SN ALJU11001-999999, SN B37811001-999999, SN B3Z711001-999999 |
| T630 | SN A7PU11001-11663, SN A7PU11664-99999 |
| T650 | SN A3P012214-099999, SN A3P111242-199999 |
| T750 | SN ANKA11001-A99999 |
| T770 | SN A3P811001-899999, SN A3P911001-999999 |
| T870 | SN A3PG11001-99999, SN A3PH11001-99999 |
Frequently asked questions
What does Bobcat code M7504 mean?
It means the gateway controller has lost CAN communication with the drive or drive plus controller. The two controllers normally talk over a CAN bus, and M7504 flags when that link goes silent.
Is M7504 the same as panel code 75-04?
Yes. M7504 is the software fault code and 75-04 is the same fault displayed in the older two-part panel numbering format.
Can I keep operating the machine with M7504 active?
It's not recommended. Since this fault affects communication with the drive controller, drive response could be affected or inconsistent. Diagnose and repair it before relying on the machine for regular work.
What conditions have to be true for M7504 to set?
The key switch has to be in the run/enter position and PTOL has to be enabled. Both conditions must be met for the gateway controller to flag the loss of communication.
Why does my M7504 code come and go instead of staying on?
Intermittent CAN faults are usually caused by loose connections, corrosion, or pins pushed back in a connector rather than a fully failed wire or controller. Because the connection is marginal, vibration or temperature changes can make the fault appear and disappear.
Which Bobcat models can throw an M7504 code?
It applies across the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770 line, and also the T870.
How do I clear M7504 after fixing the wiring or connector issue?
Cycle the key power off and back on. That is the only clearing step listed for this code.