How do I fix Internal CAN Communication Failure on a Growatt?

Check all Link0/Link1 cables between ARK modules — each cable must be fully seated at both ends. Verify the end-of-chain termination plug is fitted in the Link1 port of the last (bottom) module Then: Power down stack (circuit breaker off). Reseat all Link cables. Power up and check if fault clears. Try replacing the inter-module cable if available

Growatt

ARK: Int CAN Fail

Internal CAN Communication Failure

RS485/CAN communication between the BDC controller and one or more ARK battery pack modules has failed. BMS ALM LED flashes red.

Common causes

Link0/Link1 inter-module cable not seatedEnd-of-chain termination plug missing from last module Link1 portDamaged inter-module comms cableFaulty battery pack module

What to check

STEP 1

Check all Link0/Link1 cables between ARK modules — each cable must be fully seated at both ends. Verify the end-of-chain termination plug is fitted in the Link1 port of the last (bottom) module

STEP 2

Power down stack (circuit breaker off). Reseat all Link cables. Power up and check if fault clears. Try replacing the inter-module cable if available

Escalate if

Fault persists after reseating all cables and fitting termination plug — faulty module or controller, escalate

Need full interactive diagnosis?

Faultpath walks you through decision trees, fault codes, and commissioning — built for solar & battery engineers.

Open Faultpath