Bobcat M3204 (32-04) Fault Code: ACS in Error
Also shown on the panel as 32-04 · Also called ACS (AHC) No Communication to OEM Controller
ACS in Error · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
Bobcat fault code M3204 (panel form 32-04) means the gateway controller has lost CAN communication with the ACS controller. It sets with the key switch on and Press To Operate Loader (PTOL) enabled, and it is cleared by cycling power once the wiring or controller issue is fixed.
Medium severity. M3204 is a communication fault, not a direct engine or hydraulic shutdown code. However, if the ACS controller is part of your machine's attachment or control system, losing communication with it can disable related functions until the fault is fixed. Diagnose it within the shift rather than ignoring it.
What does Bobcat error code M3204 mean?
M3204 is Bobcat's code for a lost CAN (Controller Area Network) communication link between the gateway controller and the ACS controller, described in the OEM text as 'ACS (AHC) No Communication to OEM Controller' or 'ACS in Error'. The gateway controller acts as a hub that routes messages between different control modules on the machine. When it stops hearing from the ACS controller, it logs this code.
The CAN network uses paired wires for each communication channel. Wire numbers starting with 91xx and 95xx carry CAN high, and wire numbers starting with 92xx and 96xx carry CAN low. A problem on either side of this pair, or a total loss of power or ground to the ACS controller, can break the link and trigger M3204.
This code shows up across a wide range of Bobcat skid-steer and compact track loader models, including the S510 through S770 and T550 through T870 lines. The wiring and fuse numbers can vary slightly by model and production year, which is why you may see references to different fuses (FC1 fuse 3 or FRC1/fuse 12) in different documentation versions for the same code.
Common causes of M3204
- ACS controller not connected (unplugged or disconnected harness connector).
- Blown fuse: depending on the model documentation, this is listed as FC1 fuse 3, FRC1 fuse 12, or simply fuse 12.
- Supply wires 1180 or 1190 open (no power reaching the ACS controller).
- Switched wire 1740/1760 shorted to ground or open.
- Ground wires 2260, 2270, or 2280 open (poor or missing ground path).
- CAN communication wires (91xx/95xx for CAN high, 92xx/96xx for CAN low) shorted to supply voltage, shorted to ground, or open.
- A fault in the ACS controller itself.
- Moisture, corrosion, or pushed-back pins in the ACS controller connectors, gateway controller connectors, ACS harness, AWS/SJC harness, or the mainframe harness.
- Intermittent faults: if the code is not active during testing, the cause may not be identifiable right away. Likely culprits still include loose connections, corrosion, pushed-back pins, the controller itself, the wire harness, or some combination of these.
How to troubleshoot Bobcat M3204: first checks
- Confirm the key switch is on (run/enter position) and that Press To Operate Loader (PTOL) is enabled, since these are the conditions under which the code sets, then check whether M3204 is currently active or stored.
- Verify the ACS controller connector is fully seated and not unplugged.
- Check the relevant fuse (FC1 fuse 3, FRC1 fuse 12, or fuse 12 depending on your model's documentation) and replace it if blown.
- Inspect supply wires 1180 and 1190 for continuity and check switched wire 1740/1760 for shorts to ground or an open circuit.
- Check ground wires 2260, 2270, and 2280 for continuity and clean, tight ground connections.
- Inspect the CAN communication wires (91xx/95xx and 92xx/96xx) for shorts to supply voltage, shorts to ground, or open circuits.
- Open and inspect the ACS controller connectors, gateway controller connectors, ACS harness, AWS/SJC harness, and mainframe harness connectors for moisture, corrosion, or pushed-back pins.
- If the code will not reproduce during testing, treat it as intermittent and focus on connection integrity: wiggle-test harness connectors and look closely for corrosion or partially backed-out pins.
How the code clears
Once the wiring, fuse, connector, or controller issue has been repaired, the code is cleared by cycling power (turning the key switch off and back on). No separate clearing step is listed.
Affected models and serial ranges
M3204 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 M3204 mean?
It means the gateway controller on your Bobcat machine has lost CAN communication with the ACS controller. It's a network communication fault, not a direct mechanical or hydraulic failure code.
What is the panel display code for M3204?
On the machine's display panel, this fault shows as 32-04.
Which Bobcat models can show M3204?
M3204 is documented across many Bobcat loader models, including the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770, and T870.
Will cycling the key clear M3204?
Cycling power will clear the code only after the underlying cause (bad fuse, open wire, bad connector, or failed controller) has actually been repaired. If the root cause is still present, the code will return.
Why does M3204 come and go intermittently?
Intermittent CAN faults are often caused by loose connections, corrosion, or pins that have pushed back out of their connector bodies. If the fault isn't active when you test it, you may need to wiggle-test harnesses and inspect connectors closely rather than relying on a live fault reading.
Is M3204 safe to keep operating with?
Since M3204 involves loss of communication with a controller, it's best to diagnose it before continuing normal operation, especially since the code is tied to conditions where Press To Operate Loader (PTOL) is enabled. Continuing to run with a broken communication link can affect related machine functions.
What's the difference between CAN high and CAN low wires on this code?
On Bobcat's wiring, CAN high wires start with 91xx or 95xx, and CAN low wires start with 92xx or 96xx. Both sides of this paired network wiring need to be intact for the ACS controller to communicate properly with the gateway controller.