U0157

Code

HYUNDAI U — Network/User

Lost Communication With Information Center “B”

Brand: HYUNDAI

Type: U — Network/User

Views: UK: 15 EN: 20 RU: 14

AI status

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Page language: EN

Causes

Open or short in CAN bus wiring (CAN High or CAN Low)
Loose, corroded or damaged connector at the information center or gateway/BCM
Faulty Information Center "B" module (internal failure)
Blown fuse or loss of module power/ground
Bus termination resistor missing or damaged (incorrect bus impedance)
Aftermarket electronic device interfering with CAN traffic

Symptoms

Information center display blank, frozen, or unresponsive
Missing or incorrect instrument/driver information (trip, fuel, messages)
Multiple modules report U-codes or loss of communication messages
Illumination of warning lamps (possible MIL or cluster warnings)
Intermittent loss of related functions (e.g., settings, trip recorder)
No communication with information center when using a scan tool

What to check

Use a scan tool to confirm U0157 is current and note any associated freeze frame or time stamps
Scan other modules for additional U-codes to identify affected network segments
Verify battery voltage is within specification (engine off and engine running)
Inspect fuses and relays related to the information center and gateway/BCM
Visually inspect connectors and wiring at the information center, BCM/gateway, and junction points for damage/corrosion
Measure CAN bus voltages (CAN High and CAN Low) at the information center connector with key ON, engine OFF

Signal parameters

CAN High (recessive): approximately 2.5 V (typical range ~2.3–2.7 V)
CAN Low (recessive): approximately 2.5 V (typical range ~2.3–2.7 V)
Dominant state: CAN High rises toward ~3.5 V and CAN Low falls toward ~1.5 V (differential ≈ 1.5–2.5 V)
Differential voltage during dominant bit: typically ≥ 1.0–1.5 V
Bus termination: total between CAN H and CAN L ≈ 60 Ω (two 120 Ω terminators in parallel)
Typical CAN baud rate for vehicle networks: often 500 kbps for high-speed CAN (verify model-specific speed)

Diagnostic algorithm

Confirm DTC: Connect a capable scan tool, verify U0157 is present, record freeze-frame data and check for other U-codes.
Check vehicle power: Verify battery voltage and inspect fuses/relays for the information center and gateway/BCM circuits.
Visual inspection: Inspect harnesses, connectors and pins at the information center, BCM/gateway, junction blocks and any recent repair/aftermarket connection points.
Check CAN voltages: With ignition ON (engine OFF), measure CAN H and CAN L at the information center connector. Compare to expected ranges listed above.
Check bus continuity/termination: With ignition OFF, measure resistance between CAN H and CAN L at multiple points. Expect ≈60 Ω. If open or drastically different, trace wiring for open/short.
Isolate segment: If possible, disconnect the information center module and verify whether the rest of the network regains normal communication. If removing the module clears network faults, suspect the module or its connectors.
Inspect for shorts: Check for CAN lines shorted to battery or ground where voltages deviate from expected values.
Wiggle test: With scan tool monitoring live CAN traffic, wiggle harnesses and connectors to reproduce intermittent communication loss.
Check for aftermarket devices: Temporarily remove/tap-off any non-factory modules connected to CAN and retest.
Software/service actions: If wiring and voltages are good, check for required reprogramming or configuration updates for the information center after replacement. Replace the module only after confirming wiring and power GOOD.
Clear codes and verify: After repair or replacement, clear DTCs, re-check network communication and perform road/static test to confirm the issue is resolved and code does not return.

Likely causes

Damaged connector or pin corrosion at information center or BCM
Short to battery or ground on CAN High or CAN Low at/near the information center
Failed information center module
Faulty or missing termination resistor (open/incorrect resistance)
Low supply voltage to the module (fuse, relay, harness damage)
Recent aftermarket installation tapping the CAN bus

Fault status

⚠️ Status

Lost communication with Information Center "B" — the module is not sending or receiving expected CAN messages on the vehicle network.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours

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U0157 — Lost Communication With Information Center “B”