Troubleshooting a Honda ATV that Won’t Start

When you’re ready to ride your Honda ATV but nothing happens when you turn the key, not even a light coming on, it’s time to troubleshoot that no-start condition.

Obviously the sooner you find and fix the problem, the sooner you can hit the trails. Here are some troubleshooting steps that should get your ATV to fire up again. 

Tools - Honda ATV No-Start Troubleshooting

• Multimeter
• Jumper wire

NOTE: We worked on a Honda TRX400EX to diagnose the problem, but the same or similar troubleshooting steps can be applied to most ATV makes and models.

Step 1: Test the Battery Voltage

Set a multimeter to DC volts, and put the positive and negative leads from the multimeter onto the positive and negative terminals on the battery. 

The reading on a healthy, fully charged battery should be somewhere between 12.5 to 13 volts. If you know the battery is charged but the volt reading is below 12 volts, the battery needs replacing. However, if the voltage checks out, you can rule out the battery being the problem and move on to the next most likely culprit.

Step 2: Test the Main Fuse

Many ATVs have a main fuse that controls the electrical supply to the entire machine. On the Honda TRX 400 EX, the fuse is located in a protective housing near the battery.

Remove the housing’s cover and the main fuse. The fuse should be a 15 amp and must be replaced if it’s the wrong ampage or if the filament is blown. There should be a spare 15A fuse within the housing, which you can use to replace the blown fuse if necessary. If the fuse is sound but the machine still won’t start, the next step is to test the solenoid and starter motor.

Step 3: Test the Solenoid & Starter Motor

ATVs rely on a solenoid or starter solenoid and a starter motor to fire up the engine. The solenoid or starter solenoid is a relay switch that closes or completes the electrical circuit to the starter motor. The starter motor is an electrical motor that turns over the engine, enabling it to start.

The solenoid on the Honda TRX 400 is located just below the main fuse housing. To test the solenoid, disconnect it from the battery, attach a jumper wire to the yellow wire with a green stripe coming from the solenoid, and attach the other end of the jumper cable to the negative battery terminal. Next, take the yellow wire with the red stripe coming from the solenoid and hold it against the positive battery terminal.

If the engine fails to turn over when the solenoid and battery are connected and there’s no audible “click” from the solenoid, the solenoid or starter solenoid has failed and must be replaced. If the engine fails to turn over when the solenoid and battery are connected but there’s an audible “click” from the solenoid indicating it’s working, the starter motor has failed and must be replaced.

If the problem with your Honda TRX 400 ATV is a weak battery or it’s simply not charging, watch the video above to see how to test the charging system (stator, rectifier and battery).