Bobcat H7404 (74-04) Fault Code: Gateway Controller No Communication
Also shown on the panel as 74-04 · Also called Gateway Controller no Communication, Main Controller No Communication
Gateway Controller No Communication · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
H7404 (panel form 74-04) sets when the auxiliary controller (or on some machines the deluxe MX controller) loses CAN communication with the gateway controller or display controller. It shows up any time the key switch is in run/enter, and it points to a supply, ground, or CAN wiring problem, or a fault in one of the controllers themselves.
High severity. Loss of CAN communication between controllers can affect machine functions that depend on that data link, so the machine should be diagnosed before returning to normal work. It is not usually an immediate engine or hydraulic damage risk, but operating with unreliable controller communication is not safe practice.
What does Bobcat error code H7404 mean?
H7404 means the auxiliary controller has lost CAN communication with the gateway controller. On machines with a deluxe MX controller, the same code text applies to loss of communication between the deluxe MX controller and the display controller. CAN (Controller Area Network) is the digital wiring network that lets the machine's controllers talk to each other, so when one side stops hearing from the other, the system flags it.
The wiring naming helps narrow the fault: wires starting with 91xx are CAN high and wires starting with 92xx are CAN low on the auxiliary/gateway pairing. On the deluxe MX/display pairing, wires starting with 95xx are CAN high and wires starting with 96xx are CAN low. A break, short to ground, or short to battery on either of these lines can knock out the link.
Because this is a communication fault between two controllers rather than a single sensor reading, the cause can be in the wiring, the connectors, or either controller itself.
Common causes of H7404
- Gateway controller battery supply wire 1110 or 1130 shorted to ground or open.
- Gateway controller ground wire 2500 or 2510 open.
- CAN communication wire 91xx or 92xx shorted to battery, shorted to ground, or open.
- Gateway controller fault.
- Auxiliary controller fault.
- Moisture, corrosion, or pushed-back pins in the drive/drive plus controller connectors, ACS controller connectors, ACD controller connectors, or Bobcat/OEM controller connectors.
- On deluxe MX equipped machines: display controller supply wire 1110 or 1120 shorted to ground or open, display controller ground wire 2100 or 2110 open, CAN wire 95xx or 96xx shorted to battery/ground or open, a display controller fault, a deluxe MX controller fault, or moisture/corrosion/pushed-back pins in the deluxe MX control harness, deluxe MX power harness, mainframe harness, ACD controller, display controller, or deluxe MX controller connectors.
- If the code is intermittent and not present at the time of testing, the cause may not be found right away. Loose connections, corrosion, pushed-back pins, a controller, the wire harness, or a combination of these can all be probable causes.
How to troubleshoot Bobcat H7404: first checks
- Turn the key switch to run/enter and confirm the code is active before doing any wiring work, since this code is present under that condition.
- Inspect the gateway controller (or display controller on deluxe MX machines) connectors for moisture, corrosion, and pushed-back pins.
- Check the drive/drive plus, ACS, and ACD controller connectors, and on deluxe MX machines the deluxe MX control harness and power harness connectors, for the same issues.
- Check gateway controller battery supply wires 1110 and 1130 (or 1110/1120 on the display controller side) for an open circuit or a short to ground.
- Check gateway controller ground wires 2500 and 2510 (or 2100/2110 on the display side) for an open circuit.
- Trace the CAN high and CAN low wires (91xx/92xx, or 95xx/96xx on deluxe MX machines) for a short to battery, short to ground, or open condition.
- If the fault will not reproduce during testing, treat it as intermittent and inspect connectors and harness routing closely for loose pins, corrosion, or chafe points rather than assuming there is no fault.
How the code clears
Once the wiring or controller issue is repaired, the code is cleared by cycling power (turning the key off and back on). No separate clearing procedure or reset step is listed beyond that.
Affected models and serial ranges
H7404 appears in our records across 18 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| E35 | SN A93K110001-99999, SN AC2P11001-99999 |
| E45 | SN AHHC11001-99999 |
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-99999 |
| 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 A39511001-99999, 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 H7404 mean?
It means the auxiliary controller has lost CAN communication with the gateway controller, or on deluxe MX equipped machines, the deluxe MX controller has lost communication with the display controller. It sets whenever the key switch is in run/enter.
Is H7404 the same as fault code 74-04?
Yes, 74-04 is the numeric panel form of H7404 on Bobcat displays.
What wires should I check first for H7404?
Start with the CAN high and CAN low wires: 91xx and 92xx for the auxiliary/gateway controller pairing, or 95xx and 96xx for the deluxe MX/display pairing. Also check the battery supply wires (1110/1130 or 1110/1120) and ground wires (2500/2510 or 2100/2110) feeding the affected controller.
Can corrosion or a loose connector cause H7404?
Yes. Moisture, corrosion, or pushed-back pins in the drive/drive plus, ACS, ACD, gateway, display, or deluxe MX controller connectors are all listed causes, and these are common with intermittent versions of this code.
Why does H7404 come and go instead of staying on?
Intermittent CAN faults are often caused by loose connections, corrosion, or pushed-back pins that only interrupt communication under certain conditions like vibration or moisture. If the code isn't active during testing, the exact cause may not be found on that visit.
How do I clear H7404 after a repair?
Cycle the key switch off and back on. That is the only clearing step listed for this code.
Which Bobcat machines can show code H7404?
It applies across a range of Bobcat compact excavators and skid-steer/track loaders, including the E35, E45, S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, T770, and T870.