# Service bulletin 2121.4

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: 11035741
- Published by NHTSA: 2026\-08\-05
- Manufacturer's number: 2121.4
- Manufacturer's date: 2026\-07\-29
- NHTSA component: VEHICLE SPEED CONTROL; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL
- Manufacturer's system: Electrical

## NHTSA's summary

ACC Dynamic Calibration Fault C110300

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11035741-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11035741-9999.pdf)

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

## Components

Driver assistance, Throttle and cruise control, Adaptive cruise control

## Trouble codes named

C1103

## Vehicles listed

- 2019 to 2025 PORSCHE CAYENNE

## Other bulletins for the same vehicles and component

- [No. 2606\-1](/bulletins/11037063.md), 2026-09-04, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; FORWARD COLLISION AVOIDANCE: WARNINGS; ENGINE; VEHICLE SPEED CONTROL. Information on Advanced Technical Information for E3II V8 Cayenne – Various Assistance System Warning Messages in the Instrument Cluster due to Implausible Drivetrain Coordinator Status
- [No. 2606](/bulletins/11037062.md), 2026-09-04, Service bulletin: FORWARD COLLISION AVOIDANCE: WARNINGS; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; ENGINE; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; VEHICLE SPEED CONTROL. Information on Advanced Technical Information for E3II V8 Cayenne – Various Assistance System Warning Messages in the Instrument Cluster due to Implausible Drivetrain Coordinator Status
- [No. 11\-25\-4](/bulletins/11037046.md), 2026-09-04, Service bulletin: FORWARD COLLISION AVOIDANCE: WARNINGS; LANE DEPARTURE: ASSIST; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; BACK OVER PREVENTION: REARVIEW SYSTEM BRAKING; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING. Technical Information for White Messages Regarding Driver Assistance Systems in Conjunction with Passive Fault Memory Entries in the ZFAS Control Unit
- [No. 11\-25](/bulletins/11027134.md), 2026-01-06, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; LANE DEPARTURE: ASSIST; LANE DEPARTURE: WARNING; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; FORWARD COLLISION AVOIDANCE: WARNINGS. Technical information for Various Error Messages Regarding Driver Assistance Systems in the Instrument Cluster in Conjunction With Passive Fault Memory Entries in the Driver Assistance Systems Control Unit \- ZFAS
- [No. 75\-25\-1](/bulletins/11026410.md), 2025-12-05, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; FORWARD COLLISION AVOIDANCE: WARNINGS; LANE DEPARTURE: ASSIST; LANE DEPARTURE: WARNING. Technical information for Various White Messages Regarding Driver Assistance Systems In the Instrument Cluster/Fault Memory Entry "C12D5FA" In the Control Unit for Driver Assistance Systems
- [No. 2503.3](/bulletins/11026391.md), 2025-12-05, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; LANE DEPARTURE: ASSIST. Instructions on advanced technical information for Troubleshooting Advanced Driver Assistance Systems \(ADAS\)
- [No. 2503.2](/bulletins/11021643.md), 2025-08-06, Service bulletin: LANE DEPARTURE: WARNING; LANE DEPARTURE: ASSIST; FORWARD COLLISION AVOIDANCE: WARNINGS; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING; FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL. Instructions on advanced technical information for troubleshooting ADAs systems
- [No. 2121.3](/bulletins/11021356.md), 2025-08-04, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL. Instructions on advanced technical information for the Cayenne \- ACC Dynamic Calibration Fault C110300
- [No. 2503.1](/bulletins/11020513.md), 2025-07-09, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; LANE DEPARTURE: WARNING; LANE DEPARTURE: ASSIST; FORWARD COLLISION AVOIDANCE: AUTOMATIC EMERGENCY BRAKING. Instructions on advanced technical information for the advanced driver assistance systems. Please refer to PDF attached for more information regarding this.
- [No. 2121.2](/bulletins/11005768.md), 2024-08-06, Service bulletin: FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL; ELECTRICAL SYSTEM. Instructions on advanced technical information for the Cayenne \- dynamic calibration fault C110300

JSON: [/v1/bulletins/11035741](/v1/bulletins/11035741)

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