Low Fuel Level Warning, Tank Near Empty
What does MAGNUM-6 mean?
The MAGNUM-6 (Magnum) diesel fault code means: Low Fuel Level Warning, Tank Near Empty. This is a moderate severity code.
Common Symptoms
- Magnum CONNECTED controller LCD or operator panel LED fault display shows fault code 6
- Yellow or amber warning lamp illuminates on the operator panel
- Tower continues to run but audible alarm or beep may sound intermittently
- Fuel gauge or fuel level indicator reads low or near empty
- Unit may shut down shortly after fault appears if fuel is not added
- Engine RPM may hunt or surge if fuel pickup is drawing air near tank bottom
- Fault code 6 remains displayed even after resetting until fuel level is restored
Probable Causes (Ranked by Likelihood)
- Fuel tank is genuinely low or near empty after extended run time Very Likely
- Fuel sender unit or float arm is stuck in the low position giving a false reading Likely
- Wiring or connector between fuel sender and controller panel is corroded or loose Possible
- Fuel sender ground wire is open, pulling the signal to a false low reading Possible
- Fuel leak from tank, line, or fitting causing actual fuel loss faster than expected Possible
- Controller has lost calibration reference for the fuel level input Less Likely
- Debris or water contamination in tank blocking fuel pickup and causing erratic level readings Less Likely
Step-by-Step Diagnostic Procedure
Check the physical fuel level first. Remove the tank cap and use a clean dipstick or flashlight to visually confirm how much fuel is actually in the tank. If the tank is low, add diesel and see if the fault clears after a minute of run time.
Inspect the entire fuel system visually for leaks. Look under the tank, along all fuel lines, and at every fitting connection. Fresh diesel staining or wet spots confirm a leak that needs to be fixed before refueling solves anything.
Locate the fuel sender unit on the tank, usually a float and arm assembly accessed from the top of the tank or through a side port. Disconnect the sender connector and measure resistance across the sender terminals with a multimeter. A typical float sender will read low ohms when full and higher ohms when empty, or vice versa depending on the unit. Compare your reading to the spec in the Magnum service manual for your model. A reading stuck at one extreme suggests a failed sender.
With the sender connector still disconnected, measure DC voltage on the signal wire going back to the controller. You should see a reference voltage from the controller, typically 5V DC. No voltage on that wire points to a wiring or controller issue.
Inspect the sender wiring harness from the tank back to the controller panel. Look for chafed insulation, corroded terminals, and loose connector pins. Rental yard units get dragged through job sites, and wiring damage is common. Repair any obvious damage and recheck the fault.
Check the sender ground wire. With the sender connected and the unit running, measure resistance from the sender ground pin to a known chassis ground. More than 1 ohm of resistance on that ground circuit can pull the level signal low and trigger a false fault 6.
If fuel level is confirmed full, sender resistance checks good, and wiring is intact but the fault persists, the controller input channel may need recalibration or the controller panel may have an internal fault. At this point you need a Magnum dealer or service technician with access to the controller programming interface.
Frequently Asked Questions
What does Magnum fault code 6 mean?
Code 6 means the controller has detected that the fuel level in the diesel tank has dropped below the low-level threshold. The unit is warning you to add fuel soon. If you ignore it, the engine will eventually run out of fuel and shut down, and you may need to bleed the fuel system before it restarts.
Can the light tower keep running with code 6 active?
Yes, for a short time. The tower stays running when code 6 first appears, but it is a countdown. Once the tank runs dry the engine will shut down. If your sender is faulty and giving a false reading, the unit will keep running normally but you still need to fix the sender so you know your actual fuel level.
How much does it cost to fix code 6?
If the tank is just low, it costs whatever a fill of diesel costs, typically $20-$60 depending on tank size. If the fuel sender has failed, parts run $40-$120 and most mechanics can replace it in under an hour. A shop visit for diagnosis and sender swap usually runs $150-$350 total.
Will the light tower restart after it shuts down from running out of fuel?
Not automatically. If the engine ran completely dry, air entered the fuel lines and injector pump. You will need to bleed the fuel system, which means manually priming the fuel lines and possibly cracking injector fittings to purge air before the Kubota engine will restart. Add fuel first, then plan on 10-20 minutes of bleed work or call a tech if you have not done it before.