Service bulletin 21-023-14

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.

NHTSA's summary

Flash: Transmission Shift Enhancements This bulletin involves flash reprogramming of the Transmission Control Module (TCM) with new software. The following Transmission Control Module (TCM) calibration improvements are available for vehicles equipped with WA580 Automatic Transmission (Sales Code DGJ).3.6L Wrangler Transmission shifting does not meet customers expectation while towing a loaded trailer in high ambients (>32°C/90°F). Poor performance and/or poor powertrain response when trying to accelerate from speeds >48 kph (30 mph) - Japan/Taiwan/China vehicles only. Rubicon Only.2.8L Wrangler Transmission shifts inconsistently (gear hunting) when driving up/down steep hills or when towing a trailer. Delayed Drive to Reverse shift engagement when the transfer case is in Low Range (4LO) Transmission shifting while accelerating from a stop does not meet customers expectation. Poor vehicle performance in Drive Poor vehicle performance in Auto Stick Mode. Rubicon Only.

The document

• NHTSA's copy of the document (PDF)
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The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Transmission and driveline

Listing a model year does not mean every vehicle of it is concerned: the document says which.

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