# Service bulletin DT12 Trans Chafe

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: 10190020
- Published by NHTSA: 2021\-04\-08
- Manufacturer's number: DT12 Trans Chafe
- Manufacturer's date: 2021\-03\-10
- NHTSA component: EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY; POWER TRAIN

## NHTSA's summary

DTNA received a field notification on multiple units regarding diagnostic fault codes that were found to be causing issues to the After Treatment Control Module \(ACM\). These fault codes indicated that the ACM communication message was not received by the Motor Control Module \(MCM\) which in certain cases, led to a 25% engine de\-rate situation. Further diagnosis revealed that the DT12 wiring harness was chafing and contacting the transmission TCU case. To reduce potential chafing areas, the proposed short\-term containment was to route the wiring harness using additional tie straps. This communication applies to Freightliner and Western Star vehicles built with DT12 transmissions.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10190020-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10190020-9999.pdf)

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

## Components

Equipment and accessories, Transmission and driveline

## Vehicles listed

- 2014 to 2022 FREIGHTLINER CASCADIA
- 2014 to 2021 WESTERN STAR 4900
- 2021 WESTERN STAR 49X
- 2014 to 2022 WESTERN STAR 5700

## Recalls for the same vehicles and component

- [22V338000](/recalls/nhtsa/22V338000.md), 2022-05-16: EQUIPMENT:OTHER:LABELS
- [2021174](/recalls/tc/2021174.md), 2021-03-24: Powertrain
- [21V209000](/recalls/nhtsa/21V209000.md), 2021-03-24: POWER TRAIN:CLUTCH ASSEMBLY
- [20V742000](/recalls/nhtsa/20V742000.md), 2020-11-30: POWER TRAIN:CLUTCH ASSEMBLY
- [2020488](/recalls/tc/2020488.md), 2020-10-16: Powertrain
- [20V642000](/recalls/nhtsa/20V642000.md), 2020-10-16: POWER TRAIN:CLUTCH ASSEMBLY
- [20V634000](/recalls/nhtsa/20V634000.md), 2020-10-14: EQUIPMENT:OTHER:LABELS; TIRES
- [20V211000](/recalls/nhtsa/20V211000.md), 2020-04-10: EQUIPMENT:OTHER:LABELS
- [19V137000](/recalls/nhtsa/19V137000.md), 2019-02-27: ELECTRICAL SYSTEM: INSTRUMENT CLUSTER/PANEL; POWER TRAIN:AUTOMATIC TRANSMISSION:GEAR POSITION INDICATION \(PRNDL\)
- [2018714](/recalls/tc/2018714.md), 2018-12-19: Powertrain

## Other bulletins for the same vehicles and component

- [MAN 0000072868](/bulletins/11037996.md), 2026-10-05, Other: POWER TRAIN. Detroit Transmissions Manual Update for Symptom Diagnostics — DT12 C/D Box Range Shift to Neutral with Reversing Events \(Aborts\)
- [TSB\-42\-080\-FTL](/bulletins/11035527.md), 2026-08-03, Service bulletin: POWER TRAIN. Revised Technical Service Bulletin for ABS Wheel Speed Fault Code Correction for MBSP Equipped Vehicles. Updated frequently asked questions.
- [TSB\-26\-057\-FTL](/bulletins/11033103.md), 2026-06-01, Service bulletin: POWER TRAIN. Revised Technical Service Bulletin for DT12 OVX Transmission Refresh
- [TSB\-26\-001\-DDC](/bulletins/11031992.md), 2026-05-02, Service bulletin: POWER TRAIN. Revised Technical Service Bulletin for DT12 Range Detent Diagnostic
- [ICI26\-006](/bulletins/11031973.md), 2026-05-02, Other: POWER TRAIN. Important Campaign Information for SF706 \- Revised, Reactivated
- [SF706\-DLR LTR](/bulletins/11031972.md), 2026-05-02, Service bulletin: POWER TRAIN. Revised Field Service campaign for Cascadia Axle Conversion: Adaptive Tandem \(AT\) 6x4 to New Final Drive \(NFD\)
- [SF706\-Bulletin](/bulletins/11031971.md), 2026-05-02, Service bulletin: POWER TRAIN. Revised Field Service campaign for Cascadia Axle Conversion: Adaptive Tandem \(AT\) 6x4 to New Final Drive \(NFD\)
- [TSB\-26\-001\-DDC](/bulletins/11030623.md), 2026-04-02, Other: POWER TRAIN. Technical Service Bulletin for DT12 Range Detent Diagnostic
- [ICI26\-003](/bulletins/11030493.md), 2026-04-02, Other: POWER TRAIN. Important Campaign Information letter for SF706 \- campaign suspended
- [FleetCom\_SF706](/bulletins/11029522.md), 2026-03-04, Other: POWER TRAIN. Fleet Communications for SF706 \- Cascadia axle conversion

JSON: [/v1/bulletins/10190020](/v1/bulletins/10190020)

[Report an error on this page](https://github.com/wenmar-pro/wenmar-open/issues/new?template=data_correction.yml&title=Data%20correction%3A%20Service%20bulletin%20DT12%20Trans%20Chafe&page=https%3A%2F%2Fopen.wenmarpro.com%2Fbulletins%2F10190020&vehicle=Service%20bulletin%20DT12%20Trans%20Chafe)