APP-W021
APP_w021_ECU_Temperature_Issue
Also written as APP_W021 / APP W021 / APP_w021_ECU_Temperature_Issue / app_w021_ecu_temperature_issue
Why does the exact Tesla alert ID matter?
Record the exact alert ID, including underscores, suffixes, and companion alerts. Tesla alerts that look similar can point to different modules, timestamps, and service procedures.
What does APP-W021 mean?
Tesla warning code in the Application Layer (APP) module. Heater is in a faulted state (e.g. when an open circuit is detected) Autosteer not enabled through UI Enable Autosteer signal on can Driver seat belt Unbuckled in ACC Autopilot will slowdown vehicle Messages from Electronic Stability Program (ESP) ecu are missing on party bus One or more ESP messages on party bus are missing AP starts receiving ESP messages again Autopark is degraded or unavailable Any monitored sensor or ECU reports an error Clears after reboot or when sensors errors are cleared. Parking spots may not be presented to driver. Indicates Restraint control module (RCM) ECU is MIA RCM Status and/or SDM1 messages are missing Forward collision warning issued to alert driver of drivable space violation Current vehicle trajectory may intersect with critical drivable space violation Autopilot ecu is marked as benchtop ecu. It is not supposed to be in car. Narrow camera initialization failed Warns if APP fails to receive one or more CAN msgs from ADSP APP fails to receive one or more CAN msgs from ADSP APP starts receiving all CAN msgs from ADSP AP will use emergency speaker to play chimes like AP deactivation, TOI etc
Original Description
Heater is in a faulted state (e.g. when an open circuit is detected) Autosteer not enabled through UI Enable Autosteer signal on can Driver seat belt Unbuckled in ACC Autopilot will slowdown vehicle Messages from Electronic Stability Program (ESP) ecu are missing on party bus One or more ESP messages on party bus are missing AP starts receiving ESP messages again Autopark is degraded or unavailable Any monitored sensor or ECU reports an error Clears after reboot or when sensors errors are cleared. Parking spots may not be presented to driver. Indicates Restraint control module (RCM) ECU is MIA RCM Status and/or SDM1 messages are missing Forward collision warning issued to alert driver of drivable space violation Current vehicle trajectory may intersect with critical drivable space violation Autopilot ecu is marked as benchtop ecu. It is not supposed to be in car. Narrow camera initialization failed Warns if APP fails to receive one or more CAN msgs from ADSP APP fails to receive one or more CAN msgs from ADSP APP starts receiving all CAN msgs from ADSP AP will use emergency speaker to play chimes like AP deactivation, TOI etc
Affected Tesla Models
What You May Notice
- Application Layer alert: Heater is in a faulted state (e.g. when an open circuit is detected) Autosteer not enabled through UI Enable Autosteer s
- Touchscreen may show an error for one or more apps or settings
- Feature may restore itself after a reboot
How to Diagnose and Resolve
- 1 Perform a soft reboot (hold both scroll wheels for ~10 seconds)
- 2 Check for pending OTA software updates
- 3 If the issue persists, schedule a service appointment
Severity Notes
APP-W021 is a Warning in the Application Layer system. Schedule service soon. Monitor your vehicle for additional warnings.