Campaign 23V-024

Cabin heater relay may fail, causing the coolant heater to overheat

Defect summary

Mack Trucks, Inc. (Mack) is recalling certain 2019 and 2021-2023 LRBE battery electric trucks. The cabin heater relay may fail, causing the coolant heater to overheat.

Consequence

A coolant heater that overheats can increase the risk of fire.

Remedy

Dealers will update the software for the Hybrid Powertrain Control Unit and Instrument Cluster, and install replacement relays, free of charge. Owner notification letters were mailed March 16, 2023. Owners may contact Mack customer service at 1-800-866-1177. Mack's number for this recall is SC0440.

Notes

Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.nhtsa.gov.

Source: NHTSA ODI recalls file, campaign 23V024000. Text as published by NHTSA.

Vehicles covered

One product line is covered

Owner complaints filed with NHTSA about electrical system on these vehicles: 0, of which 0 involved a crash, fire, injury or death. Complaints are not verified by NHTSA.

Vehicles covered by campaign 23V-024
Make	Model	Model years	Complaints on this component
Mack	Lrbe (electric)	2019 to 2023	0

Source: NHTSA ODI recalls and complaints files. Equipment, tire and child-seat campaigns list products, not vehicles.

Investigation

No NHTSA investigation is linked to this recall

Most recalls are started by the manufacturer. This one lists "Manufacturer" as its origin.

Before the recall

No service bulletins on this component preceded the recall

Distinct manufacturer communications on the same component group, make, model and model year in the 24 months before the report date.

Source: NHTSA manufacturer communications file.

Service bulletins

25E-078 Nov 18, 2025
Electrical noise and low signal to the power line carrier may cause the ECU to incorrectly process commands or stop working
25V-427 Jun 23, 2025
When the Controller Area Network (CAN) communications are interrupted, the throttle signal from the electro mobility control unit may retain the…
25V-382 Jun 10, 2025
Power cables may have been improperly routed, which can cause an electrical short
25V-185 Mar 25, 2025
High voltage batteries may have loose hardware that can fall inside the battery pack and create a short circuit
24V-792 Oct 23, 2024
Electrical noise and low signal to the power line carrier may cause the ECU to incorrectly process commands or stop working
24V-447 Jun 16, 2024
Incorrectly assembled high voltage connector could prevent the mechanical connector lock from properly engaging, allowing the high voltage cable…