U017487 - U017487 Lost Communication With Auxiliary Radar
Fault Severity Definition
DTC U017487 indicates a critical link failure within the vehicle's network communication architecture, specifically manifested as an inability of the central control unit or gateway module to receive valid data frames from the auxiliary radar sensor. In automotive electronic architectures, auxiliary radars typically serve as key perception components of Advanced Driver Assistance Systems (ADAS), responsible for monitoring obstacle distances and relative velocities on the sides or rear of the vehicle. This DTC belongs to the U class (Network Communication Class), meaning the issue does not stem from functional logic errors within the radar itself but rather a rupture in the information exchange link between control units. The system continuously monitors heartbeat signals and data frame integrity on the CAN bus; once message loss from a specific node exceeds the preset threshold, this fault state is triggered, causing relevant safety functions to enter fail-safe mode.
Common Fault Symptoms
When the vehicle stores DTC U017487, drivers may perceive the following system behavior abnormalities or instrument feedback during driving:
- Dashboard Warning Lights Illuminated: The combination instrument cluster may display yellow or red warning icons indicating that the ADAS system is restricted, a radar sensor fault exists, or the driver assistance system is unavailable.
- Loss of Advanced Driver Assistance Functions: Functions relying on the radar signal (such as blind spot monitoring, lane change assist, rear traffic alert, or automated parking assist) will become temporarily unavailable or automatically turn off.
- System Information Prompts: The center display or multi-function information screen may pop up text messages such as "Radar Sensor Blocked", "Assistance System Fault", or "Please Inspect Driver Assistance System".
- Intermittent Function Interruption: Under specific conditions (such as high vibration or humid environments), related assistance functions may exhibit intermittent enabling and disabling phenomena.
Core Fault Cause Analysis
Based on the physical characteristics of network communication failures, the root causes leading to DTC U017487 can be summarized into the following three technical dimensions:
- Hardware Component Dimension: The auxiliary radar sensor itself may suffer from internal electronic component damage, processor faults, or power management module failure, preventing it from generating or sending valid communication signals. Additionally, physical damage to the radar housing or internal moisture ingress could lead to a complete hardware shutdown.
- Wiring and Connector Dimension: The communication harness connecting the radar to the control unit (CAN High/CAN Low) may experience open circuits, short circuits, or shorts-to-ground/power phenomena. Connector terminal corrosion, looseness, pin backout, or excessive contact resistance can lead to signal attenuation or interruption, thereby causing communication loss.
- Controller Dimension: The gateway module or primary control unit receiving the signals may possess software logic errors or hardware interface faults, preventing it from correctly parsing messages from the radar. Furthermore, interference from other nodes in the network topology or excessive bus load could lead to arbitration failure, indirectly triggering this fault.
Technical Monitoring and Trigger Logic
The control unit determines this fault through coordinated monitoring of the Physical Layer and Data Link Layer, with specific technical logic as follows:
- Monitoring Target: The system real-time monitors the arrival status of specific Message IDs on the CAN bus and physical level signals. The control unit expects to receive state frames and data frames from the auxiliary radar within fixed time periods.
- Signal Integrity Determination: The physical layer voltage of the communication link must be maintained within standard differential signal ranges; typical CAN bus recessive and dominant levels must comply with ISO 11898 standards, ensuring signals fluctuate normally around the $2.5V$ baseline. If physical link voltage is abnormal, the underlying driver will directly report a bus error.
- Trigger Conditions and Logic: Fault determination is typically based on a "Timeout Counting" mechanism. When the control unit fails to receive valid signals from the auxiliary radar within continuous multiple communication cycles (e.g., consecutive loss of several data frames), and the ignition switch is on with vehicle power voltage within the normal operating range (such as $9V$~$16V$), the fault counter accumulates to the threshold, the system immediately locks DTC U017487 and illuminates the warning lamp. This monitoring remains active during both vehicle driving and parked states with power on.
meaning the issue does not stem from functional logic errors within the radar itself but rather a rupture in the information exchange link between control units. The system continuously monitors heartbeat signals and data frame integrity on the CAN bus; once message loss from a specific node exceeds the preset threshold, this fault state is triggered, causing relevant safety functions to enter fail-safe mode.
Common Fault Symptoms
When the vehicle stores DTC U017487, drivers may perceive the following system behavior abnormalities or instrument feedback during driving:
- Dashboard Warning Lights Illuminated: The combination instrument cluster may display yellow or red warning icons indicating that the ADAS system is restricted, a radar sensor fault exists, or the driver assistance system is unavailable.
- Loss of Advanced Driver Assistance Functions: Functions relying on the radar signal (such as blind spot monitoring, lane change assist, rear traffic alert, or automated parking assist) will become temporarily unavailable or automatically turn off.
- System Information Prompts: The center display or multi-function information screen may pop up text messages such as "Radar Sensor Blocked", "Assistance System Fault", or "Please Inspect Driver Assistance System".
- Intermittent Function Interruption: Under specific conditions (such as high vibration or humid environments), related assistance functions may exhibit intermittent enabling and disabling phenomena.
Core Fault Cause Analysis
Based on the physical characteristics of network communication failures, the root causes leading to DTC U017487 can be summarized into the following three technical dimensions:
- Hardware Component Dimension: The auxiliary radar sensor itself may suffer from internal electronic component damage, processor faults, or power management module failure, preventing it from generating or sending valid communication signals. Additionally, physical damage to the radar housing or internal moisture ingress could lead to a complete hardware shutdown.
- Wiring and Connector Dimension: The communication harness connecting the radar to the control unit (CAN High/CAN Low) may experience open circuits, short circuits, or shorts-to-ground/power phenomena. Connector terminal corrosion, looseness, pin backout, or excessive contact resistance can lead to signal attenuation or interruption, thereby causing communication loss.
- Controller Dimension: The gateway module or primary control unit receiving the signals may possess software logic errors or hardware interface faults, preventing it from correctly parsing messages from the radar. Furthermore, interference from other nodes in the network topology or excessive bus load could lead to arbitration failure, indirectly triggering this fault.
Technical Monitoring and Trigger Logic
The control unit determines this fault through coordinated monitoring of the Physical Layer and Data Link Layer, with specific technical logic as follows:
- Monitoring Target: The system real-time monitors the arrival status of specific Message IDs on the CAN bus and physical level signals. The control unit expects to receive state frames and data frames from the auxiliary radar within fixed time periods.
- Signal Integrity Determination: The physical layer voltage of the communication link must be maintained within standard differential signal ranges; typical CAN bus recessive and dominant levels must comply with ISO 11898 standards, ensuring signals fluctuate normally around the $2.5V$ baseline. If physical link voltage is abnormal, the underlying driver will directly report a bus error.
- Trigger Conditions and Logic: Fault determination is typically based on a "Timeout Counting" mechanism. When the control unit fails to receive valid signals from the auxiliary radar within continuous multiple communication cycles (e.g., consecutive loss of several data frames), and the ignition switch is on with vehicle power voltage within the normal operating range (such as $9V$~$16V$), the fault counter accumulates to the threshold, the system immediately locks DTC U017487 and illuminates the warning lamp. This monitoring remains active during both vehicle driving and parked states with power on.
Cause Analysis Based on the physical characteristics of network communication failures, the root causes leading to DTC U017487 can be summarized into the following three technical dimensions:
- Hardware Component Dimension: The auxiliary radar sensor itself may suffer from internal electronic component damage, processor faults, or power management module failure, preventing it from generating or sending valid communication signals. Additionally, physical damage to the radar housing or internal moisture ingress could lead to a complete hardware shutdown.
- Wiring and Connector Dimension: The communication harness connecting the radar to the control unit (CAN High/CAN Low) may experience open circuits, short circuits, or shorts-to-ground/power phenomena. Connector terminal corrosion, looseness, pin backout, or excessive contact resistance can lead to signal attenuation or interruption, thereby causing communication loss.
- Controller Dimension: The gateway module or primary control unit receiving the signals may possess software logic errors or hardware interface faults, preventing it from correctly parsing messages from the radar. Furthermore, interference from other nodes in the network topology or excessive bus load could lead to arbitration failure, indirectly triggering this fault.
Technical Monitoring and Trigger Logic
The control unit determines this fault through coordinated monitoring of the Physical Layer and Data Link Layer, with specific technical logic as follows:
- Monitoring Target: The system real-time monitors the arrival status of specific Message IDs on the CAN bus and physical level signals. The control unit expects to receive state frames and data frames from the auxiliary radar within fixed time periods.
- Signal Integrity Determination: The physical layer voltage of the communication link must be maintained within standard differential signal ranges; typical CAN bus recessive and dominant levels must comply with ISO 11898 standards, ensuring signals fluctuate normally around the $2.5V$ baseline. If physical link voltage is abnormal, the underlying driver will directly report a bus error.
- Trigger Conditions and Logic: Fault determination is typically based on a "Timeout Counting" mechanism. When the control unit fails to receive valid signals from the auxiliary radar within continuous multiple communication cycles (e.g., consecutive loss of several data frames), and the ignition switch is on with vehicle power voltage within the normal operating range (such as $9V$~$16V$), the fault counter accumulates to the threshold, the system immediately locks DTC U017487 and illuminates the warning lamp. This monitoring remains active during both vehicle driving and parked states with power on.