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ISA Speed Chime Suppression

Suppresses the ISA (Intelligent Speed Assistance) speed warning chime on HW4 vehicles.

How It Works​

The ISA system monitors speed limits and alerts the driver when exceeding them. The firmware can suppress the audible chime while still showing the visual indicator on the dashboard.

The suppression is controlled via CAN message 921 (DAS_status), which contains the DAS_suppressSpeedWarning signal.

CAN Message Details​

CAN IDBitValueSignalDescription
921131DAS_suppressSpeedWarningSuppress speed warning chime
92156-63(checksum)DAS_statusChecksumUpdate checksum
important

CAN message 921 includes a checksum in bits 56-63. When modifying this message, the checksum must be recalculated — otherwise the receiving ECU will discard the frame.

Configuration​

This feature is optional and must be explicitly enabled at compile time:

#define ISA_SPEED_CHIME_SUPPRESS

Arduino IDE​

In sketch_config.h:

// #define ISA_SPEED_CHIME_SUPPRESS

Uncomment this line and upload.

PlatformIO​

Use the command-line configuration tool:

python3 scripts/platformio_set_ino_profile.py \
  --driver DRIVER_TWAI \
  --vehicle HW4 \
  --enable ISA_SPEED_CHIME_SUPPRESS

Then build and flash:

pio run -e esp32_twai --target upload

Runtime Control (Web Interface)​

On ESP32 boards with the web interface enabled, you can toggle ISA chime suppression at runtime:

  1. Open the web interface: http://192.168.4.1 (WiFi: TeslaCAN / canmod12)
  2. Navigate to Controls section
  3. Toggle ISA Speed Chime Suppress on/off

The setting is persistent and will be restored after reboot.

Requirements​

  • HW4 vehicle only — this feature is not available on HW3 or Legacy
  • ESP32 board — OTA control via web interface requires ESP32 (RP2040/M4 can only enable at compile time)
  • Vehicle firmware that supports ISA feature

Behavior​

When enabled:

  • The audible chime is suppressed when exceeding speed limits
  • The visual indicator (speed limit sign on dashboard) remains active
  • The driver is still visually informed of speed limit violations
caution

Always stay attentive to speed limits. This feature suppresses sound only — the visual indicator is still present. Do not rely solely on the chime for speed awareness while driving.