Code
C181400
HYUNDAI
C — Chassis
CAN Message Failure - SAS
Views:
UK: 13
EN: 17
RU: 15
AI status
Completed
Completed
100%
Causes
- Open/short or intermittent wiring between SAS and CAN bus
- Poor connector contact or corroded terminals at SAS or gateway module
- Power or ground fault to the SAS or its control module
- Defective SAS (sensor/module) or other CAN node
- CAN bus wiring fault (short to battery/ground, shielding damage)
- Missing/incorrect CAN termination resistor(s)
Symptoms
- ABS/ESC or traction control warning lamp illuminated
- Steering angle data missing or incorrect in scan tool
- Stability control functions reduced or disabled
- Possible steering assist irregularities (depending on system)
- Related communication/fault codes present for other modules
What to check
- Scan all modules; record freeze frame and related DTCs
- Verify vehicle battery voltage and main grounds
- Inspect SAS connector and wiring for damage, corrosion, or loose pins
- Check CAN bus wiring for continuity, shorts to power/ground and proper routing
- Measure termination resistance across CAN_H and CAN_L with ignition OFF (approx. 60 ohms total)
- Use a scan tool to view live SAS data and message presence
Signal parameters
- CAN idle (recessive) voltages: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
- Dominant state: CAN_H rises (~3.5 V) and CAN_L falls (~1.5 V) when active
- Total bus termination ≈ 60 ohms (two 120 Ω resistors in parallel)
- Expected SAS message: periodic steering angle message (ID and period manufacturer-specific)
- Message frequency: typically tens of Hz (check OEM spec for exact period)
Diagnostic algorithm
- Read and document all stored codes and freeze frame data from all control modules.
- Confirm battery good state-of-charge and inspect main ground points; repair any poor grounds.
- Visually inspect steering column/SAS connectors and wiring for damage, corrosion, or pin push-out; repair as needed.
- With ignition OFF, measure resistance between CAN_H and CAN_L at a convenient diagnostic connector — expect ~60 Ω. If far off, trace for missing termination or opens/shorts.
- With key ON, measure CAN_H and CAN_L voltages at the SAS connector; compare to nominal values (≈2.5 V idle).
- Use a scan tool/oscilloscope to confirm SAS CAN messages are present and stable on the bus; check message ID and timing against OEM data if available.
- If messages are intermittent, perform wiggle tests at connectors and along harness while monitoring bus traffic and DTCs.
- Isolate by disconnecting other nearby modules (gateway/ABS) one at a time if safe to do, to identify a node causing bus contention.
- If wiring and bus health are good but messages still absent, consider replacing or reprogramming the SAS/module per OEM procedure.
- After repairs, clear codes and perform a road test to confirm no recurrence and correct SAS data flow.
Likely causes
- Loose/damaged connector at the SAS or steering column
- SAS module failure
- CAN_H/CAN_L short or high resistance in harness
- Fault in ABS/ESC/gateway module that forwards SAS messages
- Vehicle battery/ground issue affecting module operation
Fault status
Status
CAN Message Failure - SAS: The steering angle sensor CAN message is missing, invalid, or not received by the control network.
Repair difficulty: Medium
Diagnostic time: 1.5 - 3 hours
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