# Service bulletin 21\-039\-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.

- Type: Service bulletin
- NHTSA id: 10139858
- Published by NHTSA: 2018\-06\-11
- Manufacturer's number: 21\-039\-14
- Manufacturer's date: 2014\-11\-25
- NHTSA component: POWER TRAIN

## NHTSA's summary

Flash: Transmission Shift Enhancements This bulletin involves reprogramming of the Transmission Control Module \(TCM\) with the latest available software. The following TCM calibration improvements are available for vehicles equipped with the 845RE 8 speed transmission \(sales code DFL\) or 8HP70 8 speed transmission \(sales code DFD or DFK\). These improvements are listed per engine application.3.0L gas engine \(sales code EHD\) Improved upshift timing. Improved torque converter engagement. Improved shift timing during tow mode operation. Improved shift points during aggressive driving. Calibration improvement to correct bump feel during 2\-1 downshift. Improved shift timing while in snow, base, and hill modes.3.6L gas engine \(sales code ERB\) Improved 4\-3 and 3\-2 downshifts. Improved shift timing at higher altitudes. Improved shift timing while in sand mode. Calibration improvement for multi\-gear downshift timing during passing maneuvers. Calibration improvement for intermittent delayed upshift.5.7L gas engine \(sales code EZH\) Improved upshift timing in eco, base, and hill modes and while using cruise. Improved 8\-7, 3\-2, and 2\-1 downshift timing Improved shift timing at higher altitudes. Improved torque converter engagement.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2014/MC-10139858-9999.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2014/MC-10139858-0001.pdf)

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

## Components

Transmission and driveline

## Vehicles listed

- 2015 JEEP GRAND CHEROKEE

## Recalls for the same vehicles and component

- [2016184](/recalls/tc/2016184.md), 2016-04-26: Powertrain
- [16V240000](/recalls/nhtsa/16V240000.md), 2016-04-25: POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE \(TCM/PCM/TECM\)

## Other bulletins for the same vehicles and component

- [S2623000023](/bulletins/11031337.md), 2026-04-15, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM. Power Liftgate Inoperative.
- [S2621000003 REV.A](/bulletins/11030138.md), 2026-03-18, Service bulletin: POWER TRAIN. The vehicle will exhibit a service transmission/check engine warning indicator for the following transmission models: 845RE, 8HP45, 850RE, 8HP50, 8HP70, 8HP75, 8HP75\-PHEV, 8HP75\-LCV, 8HP90, 8HP95. Transmissions may exhibit the following diagnostic codes: P07E4, P1DB2, P0716, P1B14, P0733, P1D90, P1DB7, P1B13.
- [101232](/bulletins/11010205.md), 2024-11-07, Service bulletin: POWER TRAIN. Plate \- Planetary
- [2104014](/bulletins/10232024.md), 2023-02-21, Service bulletin: POWER TRAIN. 8HP70 Transmission Shift Enhancements
- [2103914](/bulletins/10232023.md), 2023-02-21, Service bulletin: POWER TRAIN:AUTOMATIC TRANSMISSION. Transmission Shift Enhancements
- [2103814](/bulletins/10232022.md), 2023-02-21, Service bulletin: POWER TRAIN. 8HP70 SRT Transmission Shift Enhancements
- [1806714](/bulletins/10232004.md), 2023-02-21, Service bulletin: POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE \(TCM/PCM/TECM\); POWER TRAIN; ELECTRICAL SYSTEM. MIL Illumination, P1CF3 Battery Temperature Sensor Out of Range Low
- [1806314](/bulletins/10232000.md), 2023-02-21, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM. 5.7L Powertrain Diagnostic And System Improvements
- [1807414](/bulletins/10229914.md), 2023-01-17, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM. Flash: 3.0L Powertrain Diagnostic And System Enhancements This bulletin involves reprogramming the Powertrain Control Module \(PCM\) with the latest available software. The following software is being released to improve A/C compressor relay duty cycle operation to prevent ignition off battery draw.
- [W41](/bulletins/10229318.md), 2023-01-09, Service bulletin: POWER TRAIN. Customer Satisfaction Notification W41 Reprogram Powertrain Control Module

JSON: [/v1/bulletins/10139858](/v1/bulletins/10139858)

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