U0198

Code

HYUNDAI U — Network/User

Lost Communication With Telematic Control Module

Brand: HYUNDAI

Type: U — Network/User

Views: UK: 16 EN: 29 RU: 36

AI status

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Page language: EN

Causes

Blown fuse or disabled power supply to telematics module
Poor or corroded ground at telematics module or related harness
Disconnected, corroded or bent connector pins at telematics module
Damaged wiring (open/short) in CAN or wake-up circuits
CAN bus is shorted to battery or ground or has open/low resistance problems
Telematic control module is powered off, asleep, or in failed state

Symptoms

Telematic features not working (SOS, remote services, vehicle tracking)
“Telematics” or network communication warning message in instrument cluster or infotainment
Unable to communicate with telematic module via OBD-II scan tool
Other modules report related U01xx/U02xx communication DTCs
Intermittent loss of telematics services, may be ignition/wake-up dependent

What to check

Read and record freeze frame and all stored network/communication U-codes and B/C/P codes
Check battery voltage (key on and off) — verify within specification
Visually inspect telematic module connector(s), fuses, and grounds for corrosion or damage
Check for other U0xx/U1xx codes indicating gateway or bus problems
Verify fuses and relays feeding the telematic module and replace if faulty
Use scan tool to poll the telematic module; note ‘no response’ or timeout behavior

Signal parameters

Battery voltage to module: ~12V (varies with key and sleep state)
CAN bus idle voltages: CAN_H ≈ 2.5V, CAN_L ≈ 2.5V
CAN dominant states: CAN_H ≈ 3.5V, CAN_L ≈ 1.5V (approx.)
Bus termination resistance: ≈ 60 ohms measured between CAN_H and CAN_L (two 120Ω terminators in parallel)
Wake-up or ignition signal voltage per wiring diagram (often ignition-switched 12V or dedicated wake line)

Diagnostic algorithm

Verify the condition: confirm U0198 is current or history and note any related codes (record freeze frame).
Check battery voltage and recharge/replace if low; clear codes and attempt to reproduce. Low battery may prevent module wake-up.
Inspect fuses/relays and verify power to the telematic module at the fuse and at the module connector.
Inspect and secure ground connections for the module and adjacent control modules.
Using a scan tool, attempt to communicate with the telematic module. If no response, try to communicate with gateway/other modules on same CAN network to determine scope of bus failure.
Measure CAN_H and CAN_L voltages at the module connector with ignition in accessory/key-on. Compare to expected idle voltages and check for short to battery/ground.
Measure termination resistance across CAN_H and CAN_L (approx. 60 ohms). If open or abnormal, trace wiring for breaks or missing terminator.
If bus voltages are abnormal, isolate wiring segments: disconnect module and check bus state at harness side and at gateway to find segment where fault appears.
Repair wiring/connectors/fuses/grounds as found. If an offending module on the bus is identified (causing shorts or noise), disconnect it and verify bus returns to normal.
If wiring and bus are good and power/ground are correct but module won’t respond, attempt module reprogramming/reflash per manufacturer procedure. If reflash fails or module remains unresponsive, replace telematic control module.
After repairs, clear DTCs, perform full system scan, and verify telematic functions and network communication are restored. Retest after vehicle sleep/wake cycles if intermittent issue.

Likely causes

Faulty telematic control module or internal failure
Open/short in CAN High or CAN Low between module and gateway
Blown fuse or removed power/ground at module
Corroded connector at module or at an intermediate splice or gateway

Fault status

⚠️ Status

Lost Communication With Telematic Control Module — telementric module not responding on vehicle network (CAN/LIN).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours

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