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CTEK Assist helps you with everyday questions for your 12v/24v or EV Chargers and includes product information, a product selector tool, troubleshooting, user manuals, compatible accessories and much more.
CTEK Assist for SMARTPASS 120T
The error LED is lit on my SMARTPASS, what has happened?
When SMARTPASS detects a fault, it flashes specific LEDs to show where the problem is. Each LED indicates a different issue:
LED 1 flashing
A problem with the service battery.
Possible causes:
Current to the battery is too high
SMARTPASS is overheated
What happens:
The unit will try five times to start charging.
If all attempts fail, you must disconnect SMARTPASS from both batteries to restart it.
What to check:
Look for a short circuit in the cables
If overheated, charging will restart automatically once it cools
LED 2 flashing
A problem with the consumer output connected to the starter battery input.
Possible causes:
Current to the consumer output is too high
SMARTPASS is overheated
Too many devices/consumers connected
What happens:
SMARTPASS will attempt to start charging five times
If all attempts fail, disconnect both batteries to restart
What to check:
Wiring for short circuits
Reduce the number of connected consumers
Let the unit cool down
LED 3 flashing
A problem with the starter battery during maintenance charging.
Possible causes:
Current to the battery is too high
SMARTPASS is overheated
What happens:
SMARTPASS tries five times to resume charging
If all attempts fail, disconnect both batteries to restart
What to check:
Wiring for short circuits
Allow the unit to cool before retrying
LED 4 flashing
A problem with the consumer output connected to the service battery.
Possible causes:
Current draw is too high
Too many consumers connected
SMARTPASS is overheated
Service battery voltage is too low
What happens:
SMARTPASS attempts charging five times
If all fail, disconnect both batteries to restart
What to check:
Look for short circuits
Reduce connected consumers
Check the battery voltage
Allow cooling if overheated
LEDs 1, 3, and 4 flashing together
The service battery temperature is too high.
SMARTPASS will not charge if the battery is above 65°C
Charging resumes automatically once the temperature drops
If any fault persists after following these steps, inspect wiring carefully or consult support for further troubleshooting.