USM_a102 — PTC MIA
Full alert identifier: USM_a102_PTC_MIA
Alert description
One or more of the messages the vehicle controller receives periodically from the Positive Temperature Coefficient (PTC) heater electronic control unit (ECU) is not received, indicating the PTC heater ECU may be unavailable (MIA).
Potential impact
Thermal management system features depending on PTC heater functionality may be limited or unavailable.
Set condition
One or more of the expected messages from the PTC heater ECU is not received.
Clear condition
The vehicle controller starts receiving the expected messages from the PTC heater ECU.
Signals to check
These diagnostic fields are associated with USM_a102. Check the alert's Payload in Service Mode Plus for available values.
| Signal | Unit |
|---|---|
VEH Faults And Extras
USM_
|
— |
VEH Feedback Status
USM_
|
— |
VEH Rods
USM_
|
— |
VEH Sensor Status
USM_
|
— |
Check other alerts
With Service Mode Plus enabled, open Service Alerts → All. Review the other alerts for clues to the cause of USM_a102.