Code
U017C
Generic
U — Network/User
Lost Communication With Restraints System Sensor M
Views:
UK: 20
EN: 24
RU: 11
AI status
Completed
Completed
100%
Causes
- Faulty restraints system sensor (Sensor M) or internal failure
- Open, shorted, or corroded wiring or connector between sensor and network
- Loss of sensor power or ground
- Broken or improperly terminated data bus (CAN/LIN) or failed transceiver
- Module configuration or software mismatch
- Intermittent connection (water ingress, damaged harness, poor repair)
Symptoms
- Restraints warning light (airbag/SRS) illuminated
- Possible disabled airbag/passenger detection features
- Related modules showing additional U0xxx codes
- No response from Sensor M when queried with a scan tool
- Intermittent or permanent loss of sensor data (seat occupancy, buckle status)
What to check
- Read and record all U0xxx and related codes from all modules
- Visually inspect the sensor connector, wiring harness, and nearby components for damage or corrosion
- Check that sensor has proper battery/ignition power and a reliable ground
- Use a scan tool to attempt to communicate with Sensor M and observe message presence on the bus
- Check for other modules that report network faults or that act as gateways
- Inspect and test CAN/LIN termination resistors and total bus resistance
Signal parameters
- CAN bus: differential signaling between CAN H and CAN L; normal idle ≈ mid-rail, dominant ≈ ~2V differential (values vary by vehicle)
- Expected periodic 'alive' or status message from Sensor M (frequency varies by system; often multiple messages per second)
- Message ID(s) for Sensor M (refer to vehicle-specific wiring/service manual)
- Bus voltage: battery voltage present at sensor power pin when key on
- Ground continuity: low ohm connection to chassis ground
- Termination: approx. 60 ohms total across CANH–CANL (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Confirm freeze frame and related codes. Note whether fault is permanent or intermittent and whether it appears on key-on or while driving.
- Use a scan tool to request data from the restraints system and attempt to query Sensor M. Record no-response behavior and check for other U-coded communications errors.
- Visually inspect Sensor M connector and wiring for damage, corrosion, pin push-out, or water intrusion. Repair as needed.
- With connector disconnected, verify sensor power (battery or switched 12V) and ground with a DVOM. Repair open circuits or poor grounds.
- Check network continuity: measure resistance between CANH and CANL at multiple points and verify correct termination (~60 Ω). Look for shorts to battery or ground.
- Monitor CAN/LIN signals with a capable scan tool or oscilloscope while cycling connectors/wiggling harness to reproduce the fault and identify intermittent opens/shorts.
- If power/ground and bus wiring are OK but no messages are present, attempt to communicate with the sensor using a factory/advanced scan tool; if still unresponsive, replace Sensor M (or known-good module) and retest.
- If replacing the sensor, clear codes and perform full system verification; if codes return, inspect upstream modules/gateway and consider reprogramming or module replacement per manufacturer procedures.
- For intermittent issues, trace and repair any harness chafing, apply dielectric grease, secure connectors, and recheck under conditions that previously triggered the fault.
- Document repairs and confirm that restraints system warnings and communications are restored on all modules.
Likely causes
- Connector corrosion or damaged pins at sensor
- Sensor power or ground circuit fault
- CAN/LIN communication line short to battery or ground
- Missing termination or high bus resistance (open/short on CANH or CANL)
- Sensor hardware fault
Fault status
Status
Lost Communication With Restraints System Sensor M — Sensor M not responding on vehicle network (no valid messages received).
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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Code
U017C
HYUNDAI
U — Network/User
Lost Communication With “Restraints System Sensor M”
Views:
UK: 11
EN: 17
RU: 11
AI status
Completed
Completed
100%
Causes
- Faulty restraints system sensor (Sensor M) or internal failure
- Open, shorted, or corroded wiring or connector between sensor and network
- Loss of sensor power or ground
- Broken or improperly terminated data bus (CAN/LIN) or failed transceiver
- Module configuration or software mismatch
- Intermittent connection (water ingress, damaged harness, poor repair)
Symptoms
- Restraints warning light (airbag/SRS) illuminated
- Possible disabled airbag/passenger detection features
- Related modules showing additional U0xxx codes
- No response from Sensor M when queried with a scan tool
- Intermittent or permanent loss of sensor data (seat occupancy, buckle status)
What to check
- Read and record all U0xxx and related codes from all modules
- Visually inspect the sensor connector, wiring harness, and nearby components for damage or corrosion
- Check that sensor has proper battery/ignition power and a reliable ground
- Use a scan tool to attempt to communicate with Sensor M and observe message presence on the bus
- Check for other modules that report network faults or that act as gateways
- Inspect and test CAN/LIN termination resistors and total bus resistance
Signal parameters
- CAN bus: differential signaling between CAN H and CAN L; normal idle ≈ mid-rail, dominant ≈ ~2V differential (values vary by vehicle)
- Expected periodic 'alive' or status message from Sensor M (frequency varies by system; often multiple messages per second)
- Message ID(s) for Sensor M (refer to vehicle-specific wiring/service manual)
- Bus voltage: battery voltage present at sensor power pin when key on
- Ground continuity: low ohm connection to chassis ground
- Termination: approx. 60 ohms total across CANH–CANL (two 120 Ω terminators in parallel)
Diagnostic algorithm
- Confirm freeze frame and related codes. Note whether fault is permanent or intermittent and whether it appears on key-on or while driving.
- Use a scan tool to request data from the restraints system and attempt to query Sensor M. Record no-response behavior and check for other U-coded communications errors.
- Visually inspect Sensor M connector and wiring for damage, corrosion, pin push-out, or water intrusion. Repair as needed.
- With connector disconnected, verify sensor power (battery or switched 12V) and ground with a DVOM. Repair open circuits or poor grounds.
- Check network continuity: measure resistance between CANH and CANL at multiple points and verify correct termination (~60 Ω). Look for shorts to battery or ground.
- Monitor CAN/LIN signals with a capable scan tool or oscilloscope while cycling connectors/wiggling harness to reproduce the fault and identify intermittent opens/shorts.
- If power/ground and bus wiring are OK but no messages are present, attempt to communicate with the sensor using a factory/advanced scan tool; if still unresponsive, replace Sensor M (or known-good module) and retest.
- If replacing the sensor, clear codes and perform full system verification; if codes return, inspect upstream modules/gateway and consider reprogramming or module replacement per manufacturer procedures.
- For intermittent issues, trace and repair any harness chafing, apply dielectric grease, secure connectors, and recheck under conditions that previously triggered the fault.
- Document repairs and confirm that restraints system warnings and communications are restored on all modules.
Likely causes
- Connector corrosion or damaged pins at sensor
- Sensor power or ground circuit fault
- CAN/LIN communication line short to battery or ground
- Missing termination or high bus resistance (open/short on CANH or CANL)
- Sensor hardware fault
Fault status
Status
Lost Communication With Restraints System Sensor M — Sensor M not responding on vehicle network (no valid messages received).
Repair difficulty: Medium
Diagnostic time: 1-3 hours
Similar codes
Your experience will help others
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