# Service bulletin S2121000011

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: 10223274
- Published by NHTSA: 2022\-10\-17
- Manufacturer's number: S2121000011
- Manufacturer's date: 2021\-05\-17
- NHTSA component: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL:SOFTWARE

## NHTSA's summary

Long Crank With Diagnostic Trouble Code \(DTC\) U0104 ? Lost Communication With Cruise Control Module, Set.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10223274-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10223274-9999.pdf)

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

## Components

Driver assistance, Adaptive cruise control

## Trouble codes named

U0104

## Vehicles listed

- 2021 JEEP GRAND CHEROKEE

## Other bulletins for the same vehicles and component

- [S2108000236 REV.B](/bulletins/11021846.md), 2025-08-13, Service bulletin: ELECTRICAL SYSTEM; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL. Windshield HUD \(Head Up Display\) Display Features
- [08\-146\-24](/bulletins/11002755.md), 2024-07-02, Service bulletin: FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; ELECTRICAL SYSTEM; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; UNKNOWN OR OTHER; FORWARD COLLISION AVOIDANCE: WARNINGS. "Mid \- Range Radar Replacement Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● C00C4\-49 Rear Radar Module 'A' \- Internal Electronic Failure. Customers may also experience the following: ● Blind Spot Warning Mid Range Radar warning light on in instrument cluster. This bulletin involves replacing the rear Mid \- Range Radar Module."

JSON: [/v1/bulletins/10223274](/v1/bulletins/10223274)

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