Bobcat M4802 (48-02) Fault Code: Front Light Relay Error On
Also shown on the panel as 48-02
Front Light Relay Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
M4802 sets when the gateway controller sees voltage on the front lights relay feedback wire (3460 on some models, 6330 on others) when the relay was not commanded on. It's an electrical feedback fault, not a lighting failure by itself, and it sets with the key switch (run/enter) on.
Low severity. This code affects front work light operation and controller feedback, not machine propulsion, hydraulics, or engine safety systems. It's worth fixing for correct lighting and to rule out a chafed harness, but it is not an operating emergency.
What does Bobcat error code M4802 mean?
M4802, also shown as panel code 48-02, is a Bobcat gateway controller fault tied to the front work lights relay circuit. The controller commands this relay on or off, and it also reads a feedback wire back from the relay to confirm the relay did what it was told. M4802 means the controller saw voltage on that feedback wire (labeled wire 3460 on some machines, wire 6330 on others depending on model and harness revision) even though it never sent the command to turn the lights on.
In plain terms, the controller thinks the front lights relay is energized when it shouldn't be. That points to a wiring or relay problem that is feeding voltage backward into the feedback circuit, rather than a burned-out light or blown fuse.
This code is set only when the key switch (run/enter) is on, meaning the controller is actively monitoring the circuit during normal operation.
Common causes of M4802
- Controller feedback wire (3460 or 6330 depending on model) shorted to supply voltage
- Front work lights wiring (wire 6100, 6310, or 6340) shorted to supply voltage
- Faulty front work lights relay
- Faulty gateway controller
- Moisture, corrosion, or pushed-back pins in the gateway controller connectors, front light relay connectors, tailgate connector, cab harness, tailgate harness, or mainframe harness
- Intermittent causes if the code is not active at the time of testing: loose connections, corrosion, pushed-back pins, the controller, the wire harness, or a combination of these
How to troubleshoot Bobcat M4802: first checks
- Confirm which feedback wire your model uses (3460 or 6330) and locate it in the wiring diagram before probing
- Inspect the front work lights relay and its connector for corrosion, moisture, or pushed-back pins
- Check wiring 6100, 6310, and 6340 for chafing or shorts to supply voltage, especially near the tailgate and mainframe harness routing
- Inspect the gateway controller connector and the tailgate and cab harness connectors for corrosion or terminal damage
- With the key switch (run/enter) on and lights not commanded, check for unexpected voltage on the feedback wire at the relay and at the controller
- If the code is not active during testing, treat it as intermittent and focus on connector condition and harness routing rather than assuming a bad part
How the code clears
Clearing this code requires cycling power (turning the key switch off, then back on) after the repair is complete. No separate reset procedure is listed beyond the power cycle.
Affected models and serial ranges
M4802 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 M4802 mean?
It means the gateway controller detected voltage on the front lights relay feedback wire when it had not commanded the relay on. This points to a wiring, relay, or connector issue rather than a bulb or fuse failure.
Will M4802 stop my Bobcat from running?
No. This is an electrical feedback fault tied to the front work lights circuit. It does not affect engine operation, hydraulics, or drive systems.
Why does my Bobcat show two different wire numbers for this code, 3460 and 6330?
Different Bobcat models and harness revisions use different wire numbers for the same feedback circuit. Some use wire 3460, others use wire 6330. Check your specific model's wiring diagram to confirm which applies.
How do I clear M4802 after fixing it?
Cycle the key switch off and back on. That is the only clearing step listed for this code.
What if the code doesn't show up when I test it?
If M4802 is intermittent and not active during testing, the cause may not be found right away. Focus on inspecting connectors for corrosion, moisture, and pushed-back pins, and check the harness for loose connections, since these are the most common intermittent causes.
Which Bobcat models can show M4802?
Models include the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770.