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Service bulletins for the 2015 Dodge Challenger

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.

350 on file from NHTSA, as of 2026-10-19.

About P0734 on the 2015 Dodge Challenger: what the code means, and the bulletins and recalls about the same components.

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Only bulletins with trouble code: P0734 are shown. Show all

Bulletins, newest first
21-019-162022-08-08. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Transmission Shift And Drivability Enhancements This bulletin involves reprogramming of the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience an erroneous Malfunction Indicator Lamp (MIL) Illumination. Upon further investigation, the technician may find a Diagnostic Trouble Code (DTC) stored in the TCM memory. 3.6L Engine (Sales Code ERB) with 845RE Transmission (Sales Code DFL): · **Improved shift quality.** · P1DCD - TCM monitoring processor performance multiple clutches locked up. · P1B13 - Park-By-Wire unintended out of park position. · P0734 - Gear 4 Shift Incorrect Ratio. 3.6L Engine (Sales Code ERB) with 8HP45 Transmission (Sales Code DFG): · **Improved shift quality.** · Harsh 2-1 downshift or bump at low speeds. · P0734 - Gear 4 Shift Incorrect Ratio. 3.0L Engine (Sales Code EHD) with 845RE Transmission (Sales Code DFL): · **Improved shift quality.** · P1DCD - TCM monitoring processor performance multiple clutches locked up. · P1B13 - Park-By-Wire unintended out of park position.
21-006-15 REVA2018-12-10. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: 845RE Transmission Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience one or more of the following concerns. ? Malfunction Indicator Lamp (MIL) illumination with Diagnostic Trouble Code (DTC) P0734 - Gear 4 Shift Incorrect Ratio set in the TCM memory. ? Harsh or erratic 8-6 downshift during freeway driving. ? Harsh or erratic 6-4 and/or 6-3 downshift during city driving. ? Harsh or erratic upshifts while in Sport Mode. ? Less than desired downshift timing (longer time to downshift than expected). ? Less than desired downshift feel during coasting decelerations and while passing. ? Less than desired shift feel when shifting from reverse to drive or drive to reverse while the vehicle is stationary (i.e. garage shift). ? Less than desired upshift feel during normal non-aggressive driving. ? Less than desired powertrain performance at higher altitudes. ? Less than desired paddle shifter operation.
21-006-15 REV-B2018-11-26. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; POWER TRAIN. Flash: 845RE Transmission Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience one or more of the following Symptom/Condition(s) and/or a Malfunction Indicator Lamp (MIL) due to an erroneous Diagnostic Trouble Code (DTC): ? P1DCD - TCM monitoring processor performance multiple clutches locked up. ? P1B13 - Park-By-Wire unintended out of park position. ? P0734 - Gear 4 Shift Incorrect Ratio set in the TCM memory. ? Harsh or erratic 8-6 downshift during freeway driving. ? Harsh or erratic 6-4 and/or 6-3 downshift during city driving. ? Harsh or erratic upshifts while in Sport Mode. ? Less than desired downshift timing (longer time to downshift than expected). ? Less than desired downshift feel during coasting decelerations and while passing. ? Less than desired shift feel when shifting from reverse to drive or drive to reverse while the vehicle is stationary (i.e. garage shift). ? Less than desired upshift feel during normal non-aggressive driving. ? Less than desired powertrain performance at higher altitudes. ? Less than desired paddle shifter operation.
21-019-162018-06-11. Service bulletin. ELECTRICAL SYSTEM; POWER TRAIN. Flash: Transmission Shift And Drivability Enhancements This bulletin involves reprogramming of the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience an erroneous Malfunction Indicator Lamp (MIL) Illumination. Upon further investigation, the technician may find a Diagnostic Trouble Code (DTC) stored in the TCM memory. 3.6L Engine (Sales Code ERB) with 845RE Transmission (Sales Code DFL): · **Improved shift quality.** · P1DCD - TCM monitoring processor performance multiple clutches locked up. · P1B13 - Park-By-Wire unintended out of park position. · P0734 - Gear 4 Shift Incorrect Ratio. 3.6L Engine (Sales Code ERB) with 8HP45 Transmission (Sales Code DFG): · **Improved shift quality.** · Harsh 2-1 downshift or bump at low speeds. · P0734 - Gear 4 Shift Incorrect Ratio. 3.0L Engine (Sales Code EHD) with 845RE Transmission (Sales Code DFL): · **Improved shift quality.** · P1DCD - TCM monitoring processor performance multiple clutches locked up. · P1B13 - Park-By-Wire unintended out of park position.
21-041-172017-11-03. Service bulletin. POWER TRAIN; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); ELECTRICAL SYSTEM. Flash: Transmission Diagnostic and Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, a technician may find the following Diagnostic Trouble Codes (DTCs) have been set. This software update will also address some symptom/conditions listed below:3.6L Engine (Sales Code ERB) with 845RE Transmission (Sales Code DFL):During a Flash Over The Air (FOTA) radio update, the transmission shift points will default to higher shift points. The transmission will shift at high engine Revolutions Per Minute (RPM) and 7th and 8th gears may be blocked (LA and LD). Improved shift quality. P1DCD - TCM Monitoring Processor Performance Multiple Clutches Locked Up. P1B13 - Park-By-Wire Unintended Out Of Park Position. P0734 - Gear 4 Shift Incorrect Ratio. 3.6L Engine (Sales Code ERB) with 8HP45 Transmission (Sales Code DFG):During a FOTA radio update, the transmission shift points will default to higher shift points. The transmission will shift at high engine RPM and 7th and 8th gears may be blocked (LA and LD). Improved shift quality. Harsh 2-1 Downshift Or Bump At Low Speeds. P0734 - Gear 4 Shift Incorrect Ratio. 3.0L Engine (Sales Code EHD) with 845RE Transmission (Sales Code DFL):Improved shift quality. P1DCD - TCM Monitoring Processor Performance Multiple Clutches Locked Up. P1B13 - Park-By-Wire Unintended Out Of Park Position.
21-019-162016-09-14. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; ELECTRICAL SYSTEM:SOFTWARE. "FLASH: TRANSMISSION SHIFT AND DRIVABILITY ENHANCEMENTS THIS BULLETIN INVOLVES REPROGRAMMING OF THE TRANSMISSION CONTROL MODULE (TCM) WITH THE LATEST AVAILABLE SOFTWARE. A SMALL NUMBER OF CUSTOMERS MAY EXPERIENCE AN ERRONEOUS MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATION. UPON FURTHER INVESTIGATION, THE TECHNICIAN MAY FIND A DIAGNOSTIC TROUBLE CODE (DTC) STORED IN THE TCM MEMORY. 3.6L ENGINE (SALES CODE ERB) WITH 845RE TRANSMISSION (SALES CODE DFL): · **IMPROVED SHIFT QUALITY.** · P1DCD - TCM MONITORING PROCESSOR PERFORMANCE MULTIPLE CLUTCHES LOCKED UP. · P1B13 - PARK-BY-WIRE UNINTENDED OUT OF PARK POSITION. · P0734 - GEAR 4 SHIFT INCORRECT RATIO. 3.6L ENGINE (SALES CODE ERB) WITH 8HP45 TRANSMISSION (SALES CODE DFG): · **IMPROVED SHIFT QUALITY.** · HARSH 2-1 DOWNSHIFT OR BUMP AT LOW SPEEDS. · P0734 - GEAR 4 SHIFT INCORRECT RATIO. 3.0L ENGINE (SALES CODE EHD) WITH 845RE TRANSMISSION (SALES CODE DFL): · **IMPROVED SHIFT QUALITY.** · P1DCD - TCM MONITORING PROCESSOR PERFORMANCE MULTIPLE CLUTCHES LOCKED UP. · P1B13 - PARK-BY-WIRE UNINTENDED OUT OF PARK POSITION."

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.