U0127

Code

HYUNDAI U — Network/User

Lost Communication With Tire Pressure Monitor Module

Brand: HYUNDAI

Type: U — Network/User

Views: UK: 12 EN: 35 RU: 12

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Page language: EN

TPMS module (receiver/control unit) failure
Loss of power or ground to the TPMS module (fuse, wiring, ignition circuit)
Open, short, or high resistance in CAN bus wiring between TPMS module and BCM/cluster
CAN bus termination fault (missing or incorrect 120 Ω termination)
Corroded/loose connectors at TPMS module or main junctions
Body Control Module (BCM) or instrument cluster fault preventing routing of TPMS messages

TPMS warning light illuminated on instrument cluster
No tire pressure values displayed or ‘—’ / error for one or all sensors
Unable to perform TPMS sensor relearn or registration
Possible MIL or other network-related warnings
Loss of TPMS-related features (e.g., TPMS-driven alerts or some stability features depending on vehicle)

Connect a capable scan tool and verify U0127 is present in current or history; attempt to poll TPMS module if tool supports it
Check battery voltage and condition; low battery can cause network issues
Inspect TPMS module connector for corrosion, water, or bent pins; secure connector
Verify fuses and relays related to TPMS and body electronics are intact and have proper power
Use a DVOM or scope to check for CAN High/Low signals at the TPMS module connector with ignition ON
Check CAN bus continuity between TPMS module and BCM/cluster; look for opens, shorts to battery or ground

CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V
CAN bus dominant: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential signalling)
Expected bus termination: ~60 Ω across CAN_H to CAN_L (two 120 Ω terminators in parallel)
Typical TPMS message frequency: periodic broadcast from TPMS module and on request by cluster/BCM (vehicle-specific IDs and intervals)
TPMS module supply: battery voltage (approx. 12 V with engine off/ON) and module ground continuity
TPMS message identifiers and payload: vehicle/OEM-specific — consult Hyundai service data for exact CAN IDs and message format

Verify the complaint and scan for U0127. Note whether code is Current or History and any related U-codes.
Attempt to communicate directly with the TPMS module using an OEM-level scan tool. If tool cannot reach module, proceed with network/wiring checks.
Check battery voltage and main fuses/relays for TPMS power circuits; restore power/ground if missing and re-test communication.
Visually inspect connectors and wiring at the TPMS module and at intermediate harness junctions for damage, corrosion, or pin push-out.
With ignition ON, measure CAN_H and CAN_L at the TPMS module connector with an oscilloscope or multimeter; confirm idle voltages and that bus activity is present (scope preferred).
Check resistance across CAN_H and CAN_L (ignition OFF) — expected ~60 Ω. If open or very high, isolate section wiring to find open/short.
If CAN voltages are abnormal, trace and repair wiring shorts/opens or replace corroded connectors. Re-check communication after repair.
If wiring and power/ground are good but TPMS still does not respond, attempt module reset via scan tool or remove/reconnect module connector to clear corrosion; re-test.
If module remains non-communicative, substitute a known-good TPMS module if available or follow OEM bench test/reprogram procedure before replacement.
After repair or module replacement, clear codes, cycle ignition, and perform a drive or relearn procedure per Hyundai specification. Confirm code does not return.

⚠️ Status

Lost Communication With Tire Pressure Monitor (TPM) Module — CAN bus messages from the TPMS module are missing or not readable by the cluster/BCM.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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