# Service bulletin 21\-027\-15

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: 10150548
- Published by NHTSA: 2018\-12\-10
- Manufacturer's number: 21\-027\-15
- Manufacturer's date: 2015\-04\-21
- NHTSA component: ELECTRICAL SYSTEM; POWER TRAIN

## NHTSA's summary

Flash: Transmission Shift Enhancements This bulletin involves reprogramming of the Transmission Control Module \(TCM\) with the latest available software. A small number of customers may experience a Malfunction Indicator Lamp \(MIL\) Illumination. Upon further investigation, the technician may find Diagnostic Trouble Code \(DTC\) P0734 \- Gear 4 Shift Incorrect Ratio stored in the TCM memory. In addition, the following TCM calibration improvements are also available for vehicles equipped with the 845RE 8 speed transmission \(sales code DFL\). 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.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2015/MC-10150548-9999.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2015/MC-10150548-0001.pdf)

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

## Components

Electrical system, Transmission and driveline

## Trouble codes named

P0734

## Vehicles listed

- 2015 DODGE DURANGO
- 2015 JEEP GRAND CHEROKEE

## Recalls for the same vehicles and component

- [18V332000](/recalls/nhtsa/18V332000.md), 2018-05-17: ELECTRICAL SYSTEM:SOFTWARE; VEHICLE SPEED CONTROL:CRUISE CONTROL; ELECTRICAL SYSTEM:WIRING
- [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

- [S1623000028 Rev. K](/bulletins/11033975.md), 2026-06-18, Service bulletin: ELECTRICAL SYSTEM; STRUCTURE:BODY. Outside Power Fold Rearview Mirror Noise Or Loose At Pivot. Mirror Contacts Door Window Glass In The Folded Position.
- [S1623000028 REV.I](/bulletins/11033308.md), 2026-06-03, Service bulletin: ELECTRICAL SYSTEM; STRUCTURE:BODY. Outside Power Fold Rearview Mirror Noise Or Loose At Pivot. Mirror Contacts Door Window Glass In The Folded Position.
- [S2623000023](/bulletins/11031337.md), 2026-04-15, Service bulletin: POWER TRAIN; ELECTRICAL SYSTEM. Power Liftgate Inoperative.
- [S2223000022 REV.E](/bulletins/11031240.md), 2026-04-10, Service bulletin: ELECTRICAL SYSTEM. Power Liftgate Inoperative Or Intermittently Will Not Open Or Close.
- [S2608000015](/bulletins/11030266.md), 2026-03-25, Service bulletin: ELECTRICAL SYSTEM; SEATS. Memory Seat Does Not Work There Is No Response from The Seat While Pressing the Memory Seat Profiles from the Switch Diagnostic Trouble Code \(DTC\) B1D9B\-54\- Seat Horizontal Front Stop Not Learned\-Missing Calibration
- [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.
- [S2608000010](/bulletins/11030042.md), 2026-03-13, Service bulletin: ELECTRICAL SYSTEM. Active Diagnostic Trouble Code \(DTC\) B1A10\-00, B1A11\-00, B1A12\- 00, B1A13\-00\-, B1A14\-00, B1A15\-00, B1A16\-00, and B1A17\-00 in The Radio Frequency Hub \(RFH\)
- [110603](/bulletins/11030026.md), 2026-03-13, Service bulletin: ELECTRICAL SYSTEM. SPEAKER \- NONE
- [110604](/bulletins/11030025.md), 2026-03-13, Service bulletin: ELECTRICAL SYSTEM. SPEAKER \- NONE
- [9100671](/bulletins/11023329.md), 2025-09-24, Service bulletin: ELECTRICAL SYSTEM. Verify "Z" part number availability. Order a "Z" part number for all Exchange Orders: Warranty, Mopar, Customer pay and Service contract. Order "68" part number for New unsold units only.

JSON: [/v1/bulletins/10150548](/v1/bulletins/10150548)

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