C161100

Code

HYUNDAI C — Chassis

CAN Time-out EMS

Brand: HYUNDAI

Type: C — Chassis

Views: UK: 17 EN: 23 RU: 18

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Page language: EN

Malfunction indicator lamp (MIL) or warning lights illuminated
Reduced engine performance or limp-home mode if EMS loses communication with other modules
No live EMS data available on scan tool or intermittent data
Other modules may show related communication fault codes
Vehicle may fail to start if critical messages are missing

Connect a manufacturer-level scan tool and read all stored and pending DTCs; record freeze frame and live data
Check battery voltage (should be within normal range, 12.4–12.9 V engine off; 13.5–14.8 V charging) and ground connections
Visually inspect CAN connectors at EMS and gateway modules for corrosion, bent pins, or water intrusion
Inspect CAN_H and CAN_L wiring along their full route for damage, chafing or recent repairs
Check for other communication codes (U-codes) to identify which modules are not communicating
Measure termination resistance across CAN_H and CAN_L with ignition off; expected ≈60 ohms (two 120 Ω resistors in parallel)

Idle (recessive) voltage: CAN_H ≈2.5 V, CAN_L ≈2.5 V (measured to chassis ground)
Dominant message state: CAN_H ≈3.5 V, CAN_L ≈1.5 V (differential ≈2.0 V) when active
Bus differential idle ≈0 V; active differential pulses when messages present
Termination resistance: ≈60 Ω measured between CAN_H and CAN_L (ignition off)
Typical high-speed CAN baud rate for powertrain networks: commonly 500 kbps (verify factory specification)
EMS message period: periodic messages expected at defined intervals — absence beyond the module timeout threshold triggers the code

Record all DTCs and clear codes. Re-scan to see which codes return and whether C161100 reappears immediately or after driving.
Verify battery voltage and ground; poor supply can cause communication drops. Repair any battery/ground issues before continuing.
With a scan tool, check if EMS appears on the network and whether other modules report loss of communication (U-codes). Note which modules are silent.
Visually inspect CAN connectors and harness for damage at EMS, gateway, fuse/relay boxes and any splices. Repair any damaged wiring or connectors.
Measure CAN bus termination resistance across CAN_H and CAN_L (ignition off). Replace or restore missing/incorrect termination resistors if value far from ~60 Ω.
Use an oscilloscope to observe CAN_H and CAN_L for correct idle voltages and message waveform integrity with ignition on. Look for missing messages, excessive noise, stuck dominant states or voltage offsets.
If waveform shows no activity from the EMS but other modules are active, test power and ground to the EMS and confirm supply fuses and relays. Repair power/ground faults.
If a specific module is silent or injecting noise, disconnect the module (if safe) and re-check bus activity to isolate the faulty unit.
If wiring and other modules test good, consult technical service bulletins and consider reflashing or replacing the EMS per manufacturer procedures.
After repairs, clear codes and perform road test to confirm the CAN timeout does not return.

⚠️ Status

CAN bus timeout: EMS communication lost or intermittent — check CAN wiring, termination, and module connectivity.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

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