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Home / DTC / C161386 — CAN Signal Error EMS

C161386 — CAN Signal Error EMS

Detailed page for trouble code C161386.

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C161386

HYUNDAI C — Chassis

CAN Signal Error EMS

Brand: HYUNDAI
Type: C — Chassis
Views: UK: 23 EN: 44 RU: 19
AI status
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Page language: EN

Causes

  • Open/short or high resistance in CAN-High/CAN-Low wiring or connectors
  • Faulty EMS (engine control) module or other network module
  • Failed/incorrect termination resistor or missing bus termination
  • Intermittent connector contamination, corrosion, or bent pins
  • Low battery voltage or poor ground/power supply to modules
  • Gateway/module software or configuration error

Symptoms

  • Malfunction indicator lamp (MIL) or warning lights illuminated
  • Loss of engine-related data on scan tool (RPM, throttle, etc.)
  • Reduced functionality of features that require EMS data
  • Intermittent drivability issues or limp-home mode
  • Other modules reporting U‑codes or communication-related faults

What to check

  • Read and record all stored/active DTCs and freeze frame data with a full-feature scan tool
  • Check battery voltage (key on, engine off and while cranking) and main power/ground connections
  • Inspect fuses and power circuits supplying the EMS and gateway modules
  • Visually inspect CAN wiring, junctions, and connectors for damage, corrosion, or water ingress
  • Check for additional U-series or manufacturer communication DTCs
  • Backprobe EMS CAN pins to confirm presence of bus signals with a scope or multimeter

Signal parameters

  • CAN bus recessive level: CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (both) — verify on vehicle
  • CAN bus dominant level: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (typical differential ≈ 2 V)
  • Typical differential idle ≈ 0 V (recessive), dominant differential ≈ 1–2 V depending on transceiver
  • Common bus bit rates: 500 kb/s or 250 kb/s on Hyundai networks — confirm vehicle-specific rate
  • Relevant message types to check: engine RPM, throttle position, vehicle speed, diagnostic requests/responses

Diagnostic algorithm

  1. Connect a full-function OBD scan tool. Read and save all DTCs from all modules. Note timestamps and freeze frame.
  2. Attempt a communication re-test and see if DTC is active, pending, or history. Look for other U‑codes indicating network issues.
  3. Verify vehicle battery condition and main power/ground to EMS and gateway. Repair/replace as necessary.
  4. Visually inspect EMS connectors and CAN harness for damage, corrosion, moisture, or loose pins. Repair as needed.
  5. With ignition ON, backprobe CAN_H and CAN_L at EMS connector. Confirm idle voltages and that signals change while cranking or communicating.
  6. Measure termination resistance between CAN_H and CAN_L with ignition OFF (expected ~60 ohms). If out of range, trace/remove modules to locate missing/failed termination.
  7. Use a scope to view waveform quality at multiple points on the bus (near EMS, gateway, and other nodes). Look for reflections, missing frames, or bus-off conditions.
  8. If short/opens are found, isolate by disconnecting modules/junctions and rechecking bus parameters to find faulty section.
  9. If wiring and termination check good and only EMS fails to communicate, swap or bench-test EMS per manufacturer procedures or consult dealership for module reprogramming/replace.
  10. After repairs, clear codes, perform relearns if required, and road test to confirm fault does not return.

Likely causes

  • Damaged or corroded connector at EMS or nearby junction
  • Broken or chafed CAN bus wiring causing intermittent loss
  • Faulty EMS module not transmitting or receiving CAN frames
  • Missing or open termination resistor causing reflections/errors
  • Low system voltage or poor ground affecting CAN transceiver

Fault status

⚠️ Status
CAN communication fault: EMS messages invalid/missing on vehicle CAN bus; communication error recorded.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.5 - 4.0 hours

Similar codes

U0100 U0073 U0121 U0101 C1601
371

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