# Service bulletin BIG5JAN21\_42

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 10186744
- Published by NHTSA: 2021\-02\-05
- Manufacturer's number: BIG5JAN21\_42
- Manufacturer's date: 2021\-01\-13
- NHTSA component: ELECTRICAL SYSTEM

## NHTSA's summary

Multi\-ECU SOTA Update \(OS 2.0.7\) CHCM, GWM, SODL, SODR no\-start condition after completing the update due to an issue with the Gateway Module \(GWM\).

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10186744-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10186744-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system

## Vehicles listed

- 2020 to 2021 LAND ROVER DEFENDER

## Recalls for the same vehicles and component

- [26V599000](/recalls/nhtsa/26V599000.md), 2026-09-17: ELECTRICAL SYSTEM:PROPULSION SYSTEM:DC/DC CONVERTER
- [26V248000](/recalls/nhtsa/26V248000.md), 2026-04-17: ELECTRICAL SYSTEM:PROPULSION SYSTEM:DC/DC CONVERTER
- [21V424000](/recalls/nhtsa/21V424000.md), 2021-06-03: ELECTRICAL SYSTEM:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE \(TCM/PCM/TECM\)

## Other bulletins for the same vehicles and component

- [N811 Defender 15MAY26](/bulletins/11033398.md), 2026-06-04, Other: ELECTRICAL SYSTEM. Door Zone Module \- Quiescent Drain
- [N811 Defender 17APR26](/bulletins/11032421.md), 2026-05-07, Other: ELECTRICAL SYSTEM. Door Zone Module \- Quiescent Drain
- [N811 Defender 20MAR26](/bulletins/11031092.md), 2026-04-07, Other: ELECTRICAL SYSTEM. Door Zone Module \- Quiescent Drain
- [SSM76411 \- 10MAR26](/bulletins/11030751.md), 2026-04-06, Other: ELECTRICAL SYSTEM. Smart Key Deactivated message on instrument cluster and unable to start their vehicle
- [TUCC\_FEB2026\_35](/bulletins/11029600.md), 2026-03-04, Other: ELECTRICAL SYSTEM. There is a concern with the 48Volt charging system\(DC/DC\) with the vehicle.
- [TUCC\_FEB2026\_34](/bulletins/11029598.md), 2026-03-04, Other: ELECTRICAL SYSTEM. There is a concern/fault with the 48Volt MHEV system.
- [TUCC\_FEB2026\_33](/bulletins/11029576.md), 2026-03-04, Other: ELECTRICAL SYSTEM. 12V STARTUP BATTERY FLAT \- MILD HYBRID ELECTRIC VEHICLE \(MHEV\)
- [252602.027 \- 12FEB26](/bulletins/11029556.md), 2026-03-04, Service bulletin: ELECTRICAL SYSTEM. Once the vehicle is powered down via ignition cycle, it may not restart depending on remaining residual charge.
- [TUCC\_JAN2026\_25](/bulletins/11028601.md), 2026-02-06, Other: ELECTRICAL SYSTEM. There is a concern with the 48Volt charging system\(DC/DC\) with the vehicle.
- [TUCC\_DEC2025\_39](/bulletins/11027472.md), 2026-01-08, Other: ELECTRICAL SYSTEM. A battery warning light on and or electrical system failure message is displayed on instrument cluster.

JSON: [/v1/bulletins/10186744](/v1/bulletins/10186744)

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