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Campaign 20V352 Posted June 12, 2020 1,067 units

2018-2020 Mci D-Series/J4500 Recall 20V352: Alternator

RN
Reviewed by the RecallNotify editorial team
Published May 23, 2026

Recall 20V352 affects 1,067 2018-2020 Mci buses for alternator overvoltage and engine-shutdown risk. Repair is free at any franchised Mci dealer.

Mci is recalling 1,067 2018-2020 J4500, D45 Crt Le, D4005, D4500, D4505, and D4000 buses because debris, corrosion, or water can create a high-resistance path at the alternator sense stud and push voltage above the VMM limit. That fault can shut the engine down or cut power while the bus is moving, and Mci dealers will complete the repair free of charge.

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What's wrong?

The 2018-2020 Mci J4500, D45 Crt Le, D4005, D4500, D4505, and D4000 buses in this recall use dual Borg Warner 55SI alternators. The alternators make electrical power for the coach, while the sense stud and wire tell the alternator what voltage the coach needs. The Parker Vansco VMM multiplex module watches that electrical system and helps control coach functions.

On affected buses, debris, corrosion, or water around the alternator sense stud can create an unwanted electrical path to ground. That bad path can make the alternator overcharge, sending voltage above the limit programmed into the VMM module. When that happens, the coach can lose engine power and shut down.

The warning sign is a "NOT GEN" telltale on the dash. If that light appears, it points to a generator or alternator problem that needs dealer attention.

Who's affected?

Spans 6 Mci coach models across the 2018, 2019, and 2020 model years, all tied to the electrical system.

2020 Mci J4500 electrical system
2019 Mci J4500 electrical system
2018 Mci J4500 electrical system
2019 Mci D45 Crt Le electrical system
2018 Mci D45 Crt Le electrical system
Units affected1,067
Field incidentsNHTSA has logged 4 field incidents to date.

A matching year and model does not guarantee inclusion. Check your VIN to confirm whether this recall applies to your specific bus.

What's the safety risk?

An engine shutdown or power loss while the vehicle is moving increases crash risk. A "NOT GEN" telltale is the warning sign listed for this recall. If it appears, slow down when safe, move out of traffic, and schedule the repair soon. Repair is free at any franchised Mci dealer.

What should I do?

  1. Check your VIN to confirm your 2018-2020 Mci J4500, D45 Crt Le, D4005, D4500, D4505, or D4000 bus is included in this recall.
  2. Contact a franchised Mci dealer to schedule the free Parker VMM software update that raises the overvoltage threshold and addresses alternator-related engine power loss.
  3. Bring the recall notice if Mci mailed one, and reference recall number 20V352 and Mci recall SB 479 when you call.
  4. Drive cautiously until the repair is complete, and pull over safely if the bus loses engine power or shuts down.

What happens at the repair

At the dealer, an Mci technician updates the Parker VMM multiplex modules with new application code. The software raises the overvoltage threshold so the module is less likely to shut the vehicle down when alternator output rises above the prior programmed limit. The recall repair is free, including the programming work. Ask the service desk to confirm the update is complete before the bus returns to service.

Timeline

June 12, 2020 NHTSA published the recall
July 10, 2020 Dealer notification began
July 10, 2020 Dealer notification ended
July 10, 2020 Interim owner notification (was planned for this date)
July 23, 2020 Owner notification mailed

Frequently asked questions

What is recall 20V352?

Recall 20V352 covers 1,067 2018-2020 Mci J4500, D45 Crt Le, D4005, D4500, D4505, and D4000 buses with an alternator overvoltage issue. Debris, corrosion, or water flow can affect the alternator sense stud and lead to loss of engine power or shutdown.

What should I do if my 2018-2020 Mci J4500, D45 Crt Le, D4005, D4500, D4505, or D4000 is on this recall?

Check your VIN to confirm your specific bus is included in recall 20V352. If it is, contact a franchised Mci dealer to schedule the Parker VMM multiplex module code update. Reference recall number 20V352 or Mci service bulletin SB 479 when you call.

Is the recall repair free?

Yes. Federal recall law requires the manufacturer to repair the defect at no cost, and Mci dealers will install the new Parker VMM application code free of charge. Parts and labor are covered for included buses.

What is the safety risk?

The safety risk is loss of engine power or vehicle shutdown while the bus is in motion. If that happens in traffic, crash risk increases. The dealer repair changes the overvoltage threshold in the Parker VMM multiplex modules to address the shutdown condition.

When did the repair become available?

The recall repair began July 23, 2020. Because the remedy is available, included owners can contact a franchised Mci dealer or Mci customer service at 1-800-241-2947 to arrange the free software code update.

More information

NHTSA campaign pagenhtsa.gov/vehicle-recalls/20V352000
Mci customer service1-800-241-2947
NHTSA recall #20V352
NHTSA recall # (full)20V352000

Source documents

This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →