Honda FourTrax Rancher TRX420TM1 2020 Owner's Manual page 224

If the High Coolant Temperature
Indicator Lights
• If the reserve tank is low or empty, don't ride without adding
coolant (page 137). After adding coolant, turn the engine on and
check the coolant temperature gauge (Except TRX420TM1) and
high coolant temperature indicator.
If the indicator doesn't turn off, do not ride. The engine needs
repair.
Transport your ATV to your dealer (page 196).
If the temperature drops to normal, check the coolant level. If it
has gone down, add more coolant.
• Check for an oil leak.
• Check the oil level. If necessary, add the recommended oil
(page 125) to the upper level mark. If you must leave your ATV to
get oil, secure it as much as possible.
• Start the engine, and check that the coolant temperature gauge
(Except TRX420TM1) and high coolant temperature indicator
goes off.
If you are able to resume riding, continue to monitor the coolant
temperature gauge (Except TRX420TM1) and high coolant
temperature indicator frequently.
If there is an oil leak — do not ride the ATV until the leak is repaired
by your dealer (page 196).
If there's a mild coolant leak, you can ride for awhile, carefully
watching the coolant temperature gauge (Except TRX420TM1) and
high coolant temperature indicator. Be prepared to stop and add
more coolant or water. If the leak is bad, transport your ATV to your
dealer (page 196).
214 Taking Care of the Unexpected