If your golf cart has an Alltrax controller and it’s flashing red or green lights, you’re not alone. These flashing codes are diagnostic signals that tell you exactly what’s wrong—if you know how to read them.
Before assuming your controller is bad, check your batteries first. Try this DIY battery reconditioning method to revive weak batteries and restore power without spending hundreds.
What Is an Alltrax Controller?
Alltrax controllers are high-performance programmable speed controllers used in golf carts, utility vehicles, and other electric equipment. They’re known for being durable, tunable, and smart—with built-in LED status indicators that flash diagnostic codes during faults.
Where to Find the LED Status Light
The LED is usually located on the top or side of the controller housing. It flashes in patterns (e.g., one green followed by two red blinks) to indicate specific issues.
Understanding Alltrax Flash Codes
Here’s a breakdown of common blink codes for Alltrax SR, XCT, and NPX series controllers.
Alltrax Controller Flash Code Chart
| Flash Pattern | Description | Likely Cause |
|---|---|---|
| 1 Red Blink | Throttle fault | Bad throttle, loose wire, or wrong throttle type selected |
| 2 Red Blinks | Overvoltage | Battery pack voltage exceeds safe limit |
| 3 Red Blinks | Undervoltage | Battery pack voltage too low |
| 4 Red Blinks | Overtemperature | Controller is too hot, needs to cool down |
| 5 Red Blinks | Pre-charge failure | Possible resistor or solenoid issue |
| 6 Red Blinks | Throttle did not zero | Throttle not at rest position on startup |
| 7 Red Blinks | Controller memory fault | Internal error—may need replacement |
How to Reset the Controller
Try these steps first before replacing anything:
- Turn the key switch off
- Flip the Run/Tow switch to “Tow” (if applicable)
- Disconnect the main battery negative cable
- Wait 5–10 minutes
- Reconnect and return switch to “Run”
This simple power cycle may clear minor faults or communication glitches.
How to Read the LED Pattern
The LED flashes green during normal operation and red when there’s a fault.
- 1 green blink = controller boot up
- Solid green = all systems go
- Green followed by red = warning or fault
Count the red flashes to identify the issue. For example, 1 green + 3 red blinks = undervoltage fault.
Fixes Based on Flash Code
1. Throttle Fault (1 red blink)
- Check throttle wiring and connectors
- Use the Alltrax Toolkit software to verify throttle type
- Replace throttle sensor if unresponsive
2. Overvoltage (2 red blinks)
- Battery voltage too high (check charger or wrong battery pack)
- Make sure controller voltage matches cart system (36V, 48V, etc.)
3. Undervoltage (3 red blinks)
- Battery pack is discharged or weak
- Check voltage under load with a voltmeter
- Recondition weak batteries before replacing
4. Overtemperature (4 red blinks)
- Let controller cool down
- Ensure it’s not installed in a tight or hot compartment
- Add a heat sink or fan if overheating persists
5. Pre-charge Failure (5 red blinks)
- Check pre-charge resistor on the solenoid (should read 200–300 ohms)
- Replace failed resistor or solenoid if necessary
6. Throttle Not Zeroed (6 red blinks)
- Release pedal before turning cart on
- Recalibrate throttle in Alltrax Toolkit software
7. Memory Fault (7 red blinks)
- Internal issue—try resetting the controller
- If code returns, contact Alltrax support for RMA or replacement
How to Use the Alltrax Toolkit Software
The free Alltrax Toolkit allows you to:
- View real-time data
- Update throttle settings
- Monitor temperature and voltage
- Clear or monitor fault codes
You’ll need a USB to Alltrax cable and a PC. This is the most accurate way to diagnose and configure your controller.
Battery First: Don’t Ignore Voltage Drops
Most flash codes come from low voltage, weak batteries, or bad connections. Always test your battery pack under load, and recondition it before assuming the controller is the issue.
Click here to learn how to restore your batteries with this easy step-by-step method that works for most golf carts.
Conclusion
Alltrax controller codes are easy to read and troubleshoot once you know what the flashes mean. Whether it’s a throttle fault, overheat, or undervoltage issue, you can often fix it without replacing your controller.
Start with a full battery inspection, recondition any weak cells, and reset the controller. Most issues can be fixed in minutes.
Click here to start reconditioning your batteries today: Battery Reconditioning Course