Service bulletin 18-057-16

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
Type	Service bulletin
NHTSA id	10141280
Published by NHTSA	2018-06-18
Manufacturer's number	18-057-16
Manufacturer's date	2016-05-11
NHTSA component	POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE (TCM/PCM/TECM); SERVICE BRAKES, HYDRAULIC:ANTILOCK/TRACTION CONTROL/ELECTRONIC LIMITED SLIP:ABS WARNING LIGHT; POWER TRAIN:AUTOMATIC TRANSMISSION:TORQUE CONVERTER

NHTSA's summary

Flash: 3.6L Powertrain Diagnostic And System Enhancements This bulletin involves reprogramming the Powertrain Control Module (PCM) with the latest available software. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination and/or one of the following conditions. Upon further investigation, a technician may find the following Diagnostic Trouble Code (DTC) stored in the Anti-lock Brake System (ABS) Module memory: NOTE: The Diagnostic Trouble Code (DTC) is caused by a calibration in the PCM that is in conflict with the ABS Module programming. The new software flash will correct this issue. · C121C-00 - Torque Request Signal Denied.

The document

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

Brakes, Transmission and driveline, Anti-lock brakes, Automatic transmission, Torque converter, Transmission control module

Trouble codes named

C121C

Vehicles listed
CHRYSLER PACIFICA	2017

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

Other bulletins for the same vehicles and component
1802023	2024-01-02. Service bulletin. Flash: Powertrain Control Module (PCM) Updates Customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation the technician may find that one or more of the following Diagnostic Trouble Codes (DTCs) have been set: ? P0335 - Crankshaft Position Sensor Circuit (NA Only). ? P0339 - Crankshaft Position Sensor Intermittent (NA Only). Major monitor (misfire) and other diagnostics are disabled on a pending DTCs P0335 and P0339.** Software enhancement: Technicians and/or customers may report the vehicle will not pass a state smog check due to permanent fault codes which will not clear. As a result, the vehicles are not eligible to be registered in certain states. ? Corrections to allow the vehicle to clear the permanent fault codes. This bulletin involves reprogramming the PCM with the latest available software. NOTE: Four modules are required to be flashed for this update to be effective, the following modules are all to be updated along with this PCM update: ? Electronic Brake Booster Module (EBBM). ? AntiLock Brake System Module (ABS). ? Hybrid Control Processor (HCP) and Auxiliary Hybrid Control Processor (AHCP) or also known as a Power Inverter Module (PIM).
9003698	2022-10-17. Service bulletin. Sensor, Brake Pedal Please call Bing Guo on cell (248) 500-7355 or Breanne Scherbaty on cell (586) 604-4852 before replacing brake pedal sensor. Diagnostic codes and vehicle scan reports are requested for root cause analysis of the customer issue. If no response in 15 minutes, proceed with the repair.
2102717	2022-10-17. Service bulletin. This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. Some customers may experience a Malfunction Indicator Lamp (MIL) illumination.
18-057-16	2020-10-26. Service bulletin. Flash: 3.6L Powertrain Diagnostic And System Enhancements This bulletin involves reprogramming the Powertrain Control Module (PCM) with the latest available software. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination and/or one of the following conditions. Upon further investigation, a technician may find the following Diagnostic Trouble Code (DTC) stored in the Anti-lock Brake System (ABS) Module memory: NOTE: The Diagnostic Trouble Code (DTC) is caused by a calibration in the PCM that is in conflict with the ABS Module programming. The new software flash will correct this issue. · C121C-00 - Torque Request Signal Denied.
21-018-16	2018-06-18. Service bulletin. Flash: Transmission Diagnostic And Shift Enhancements This bulletin involves reprogramming the Transmission Control Module (TCM) with the latest available software. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination and/or one of the following conditions. Upon further investigation, a technician may find the following Diagnostic Trouble Code (DTC) stored in the TCM memory: · P1DDE-00 - Ignition Run/Start Input 1-2 Correlation.
9003730	2018-06-04. Service bulletin. SI-eVT Transmission - China Variant The service SI-eVT is shipped with a non-China wiring harness (68241331AC). China market replacement must replace wiring harness with 68368596AA. The China variant 68368596AA wiring harness has an interlock to the electrical charge door.
21-022-16	2016-09-14. Service bulletin. "FLASH: TRANSMISSION SHIFT AND DRIVABILITY ENHANCEMENTS THIS BULLETIN INVOLVES REPROGRAMMING THE TRANSMISSION CONTROL MODULE (TCM) WITH THE LATEST AVAILABLE SOFTWARE. SOME CUSTOMERS MAY EXPERIENCE A MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATION. UPON FURTHER INVESTIGATION, A TECHNICIAN MAY FIND THE FOLLOWING DIAGNOSTIC TROUBLE CODE (DTC) STORED IN THE TCM MEMORY: · P1CC9 - UNABLE TO ENGAGE GEAR."