2023 Mci D4520 problems, complaints & recalls
Safety recalls (1)
Electrical System: Instrument Cluster/Panel 2026-10-05 · campaign 26V645000 · 683 vehicles
Defect: Motor Coach Industries (MCI) is recalling certain 2018-2026 buses. Please see the complete list of models above. The instrument panel indicator light may not illuminate when the hazard warning lights are on and the master run switch is in the 'Off' position. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices, and Associated Equipment."
Risk: Without the illuminated reminder, the driver may fail to turn off the exterior lights when no longer needed. Hazard warning lights that remain activated unintentionally can confuse other drivers, increasing the risk of a crash.
Fix: MCI will update the software, free of charge. Owner notification letters are expected to be mailed November 24, 2026. Owners may contact MCI customer service at 1-800-241-2947.
Service bulletins (5)
Technical service bulletins are repair instructions manufacturers send dealers for known issues. Unlike recalls, the fix is not automatically free — but naming the bulletin at the service desk can save diagnosis time and support goodwill repairs.
Service Brakes 2026-08-11 · TSIB 26-07 · Service Bulletin/Repair Instructions
this bulletin is to provide instructions for clearing dtc 1067 fmi 7 (pressure sensor not calibrated) and fmi 11 (primary and secondary circuit pressure sensor (ps1/ps2) plausibility error - bs pressure), when required to prevent the loss of adaptive cruise control functionality and the illuminatio
Engine 2026-06-11 · TSIB 26-05 · Service Bulletin/Repair Instructions
this bulletin introduces an optional product improvement to the a/c compressor drive system for coaches equipped with a cummins x12. the improved pulley system is available for customers who wish to reduce noise and vibration characteristics and may be installed at the customer’s discretion.
Electrical System 2026-05-06 · TSIB 26-01 · Service Bulletin/Repair Instructions
this tsib provides information to provide a software update. some coaches using mcc hvac eco-tempo ecu # 07-10-009 software t35-1581 / v1.04 may be experiencing random fault codes due to mcc software errors.
Suspension 2026-02-09 · TSIB 26-04 · Service Bulletin/Repair Instructions
this tsib is to inform customers the recommended steering axle cleaning/greasing instructions to prevent damage on axle components due to displacement of grease from the bearings, lubrication reduction and accelerate wear for coaches with independent front suspension.
Unknown Or Other 2024-11-05 · TSIB 24-03 · Service Bulletin/Repair Instructions
information to owners showing the proper procedure for checking the oil level in a bitzer hvac compressor.
What owners report
No detailed complaint narratives on file.
Excerpts of consumer complaints filed with NHTSA, lightly truncated. They are owner statements, not verified findings.