TSB: Land Rover Coolant Woes

This bulletin applies to 202402025 Land Rover Defender, New Range Rover, Range Rover Sport and Range Rover Velar vehicles. The customer may experience poor passenger compartment heating performance and/or slow to warm up, and EV mode may not be available. DTC B1DC5-64 may be stored in the HVAC module.

The cause may be no or low coolant flow, air in the cooling system, an auxiliary passenger compartment coolant pump issue and/or incorrectly installed or faulty coolant hose.

Do not renew the HVCH if this DTC is stored. This indicates that the HVCH has had an overheat prevention event and will not operate for that drive cycle. If DTC B1DC5-93 is also stored and cannot be erased, the HVCH should be renewed.