Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / U0055 — Vehicle Communication Bus D

U0055 — Vehicle Communication Bus D

Detailed page for trouble code U0055.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

U0055

Generic U — Network/User

Vehicle Communication Bus D

Brand: Generic
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in Bus D wiring (CAN/lin/other physical layer)
  • Failed node/module (bad transceiver or controller)
  • Poor or corroded ground or power supply to one or more modules on Bus D
  • Blown fuse or defective power supply feeding Bus D modules
  • Incorrect or missing termination resistor(s) on the bus
  • Intermittent connector or pin corrosion at module harnesses

Symptoms

  • Malfunction Indicator Lamp (MIL) or dash warning(s)
  • One or more modules listed as 'not communicating' or missing in a scan tool
  • Loss of specific functions controlled by modules on Bus D (e.g., telematics, body control, infotainment depending on vehicle)
  • Intermittent operation of affected systems
  • Possible no-crank/no-start or limp-home conditions if critical modules are on Bus D

What to check

  • Use OEM scan tool to read all U-codes and identify which modules on Bus D are not responding
  • Visually inspect wiring, connectors, and harnesses for damage/corrosion around modules and along the bus route
  • Check fuses and power/ground at each module on Bus D
  • Measure CAN/communication line voltages with vehicle key in required position (see signal parameters) using a digital multimeter
  • Check continuity and short-to-ground/short-to-B+ on bus wires with power removed or using a current-limited method
  • Inspect and measure termination resistors across the bus (should be about 60 ohms for CAN with two 120 ohm terminators)

Signal parameters

  • CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
  • Typical CAN termination: two 120 ohm resistors in parallel = ~60 ohms measured end-to-end
  • Common CAN bus speeds: 500 kb/s, 250 kb/s, 125 kb/s (verify vehicle-specific speed)
  • Faulty bus may show stuck-high, stuck-low, excessive noise, or missing dominant/recessive transitions on scope

Diagnostic algorithm

  1. Retrieve all stored and pending DTCs from all modules and note freeze-frame data and which modules are non-communicating.
  2. Clear codes, then attempt to re-run network scan to see which DTCs return and whether the fault is current or intermittent.
  3. Identify all modules and wiring that share Bus D from the wiring diagram or vehicle network documentation.
  4. Visually inspect connectors, pins and harnesses at each module and along the bus path for damage, corrosion, or loose pins.
  5. Verify power and ground for each module on Bus D (check fuse(s), battery feed, and module grounds) per manufacturer precautions.
  6. With key in required position, measure idle voltages on the communication lines at a known-good connector. Compare to expected signal parameters.
  7. Measure end-to-end resistance across the bus to verify termination (about 60 ohms for a properly terminated CAN bus).
  8. Use an oscilloscope or CAN analyzer to observe bus traffic and waveform quality; look for missing frames, dominant states held, or noise.
  9. Isolate the fault by disconnecting modules or segments one at a time while monitoring the bus to find the point where communication returns.
  10. Repair any damaged wiring, replace faulty connectors or modules, and replace/fit proper termination resistors as required.
  11. Reprogram or update module software/firmware if a known update addresses communication issues, then clear codes and retest.
  12. After repair, perform full system scan and a functional test of affected systems to confirm restoration of communication.

Likely causes

  • Open or shorted wiring on Bus D (most common)
  • Failed module transceiver or internal module fault
  • Missing/failed termination resistor(s)
  • Poor ground or power feed to a module on Bus D

Fault status

⚠️ Status
Lost or invalid communication on Vehicle Communication Bus D — one or more modules on this network segment are not responding or data is unavailable.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 to 3.0 hours

Similar codes

U0100 U0073 U0105 U0121 U0140
9,546

The library contains 9,546 repair and diagnostic manuals. Choose a brand to open the full manual tree by year, model and trim.

ALFA ROMEO
89
AUDI
1,243
BMW
479
CADILLAC
206
CHEVROLET
456
CHRYSLER
193
DAEWOO
75
FIAT
26
GENESIS
207
HUMMER
138
HYUNDAI
371
ISUZU
229
KIA
155
LAND ROVER
294
LEXUS
280
LINCOLN
166
MERCEDES-BENZ
856
MERCURY
296
MITSUBISHI
406
PORSCHE
136
TESLA
58
TOYOTA
2,209
TRIUMPH
131
VOLKSWAGEN
626
VOLVO
221
Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U0055

HYUNDAI U — Network/User

Vehicle Communication Bus D

Brand: HYUNDAI
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in Bus D wiring (CAN/lin/other physical layer)
  • Failed node/module (bad transceiver or controller)
  • Poor or corroded ground or power supply to one or more modules on Bus D
  • Blown fuse or defective power supply feeding Bus D modules
  • Incorrect or missing termination resistor(s) on the bus
  • Intermittent connector or pin corrosion at module harnesses

Symptoms

  • Malfunction Indicator Lamp (MIL) or dash warning(s)
  • One or more modules listed as 'not communicating' or missing in a scan tool
  • Loss of specific functions controlled by modules on Bus D (e.g., telematics, body control, infotainment depending on vehicle)
  • Intermittent operation of affected systems
  • Possible no-crank/no-start or limp-home conditions if critical modules are on Bus D

What to check

  • Use OEM scan tool to read all U-codes and identify which modules on Bus D are not responding
  • Visually inspect wiring, connectors, and harnesses for damage/corrosion around modules and along the bus route
  • Check fuses and power/ground at each module on Bus D
  • Measure CAN/communication line voltages with vehicle key in required position (see signal parameters) using a digital multimeter
  • Check continuity and short-to-ground/short-to-B+ on bus wires with power removed or using a current-limited method
  • Inspect and measure termination resistors across the bus (should be about 60 ohms for CAN with two 120 ohm terminators)

Signal parameters

  • CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
  • Typical CAN termination: two 120 ohm resistors in parallel = ~60 ohms measured end-to-end
  • Common CAN bus speeds: 500 kb/s, 250 kb/s, 125 kb/s (verify vehicle-specific speed)
  • Faulty bus may show stuck-high, stuck-low, excessive noise, or missing dominant/recessive transitions on scope

Diagnostic algorithm

  1. Retrieve all stored and pending DTCs from all modules and note freeze-frame data and which modules are non-communicating.
  2. Clear codes, then attempt to re-run network scan to see which DTCs return and whether the fault is current or intermittent.
  3. Identify all modules and wiring that share Bus D from the wiring diagram or vehicle network documentation.
  4. Visually inspect connectors, pins and harnesses at each module and along the bus path for damage, corrosion, or loose pins.
  5. Verify power and ground for each module on Bus D (check fuse(s), battery feed, and module grounds) per manufacturer precautions.
  6. With key in required position, measure idle voltages on the communication lines at a known-good connector. Compare to expected signal parameters.
  7. Measure end-to-end resistance across the bus to verify termination (about 60 ohms for a properly terminated CAN bus).
  8. Use an oscilloscope or CAN analyzer to observe bus traffic and waveform quality; look for missing frames, dominant states held, or noise.
  9. Isolate the fault by disconnecting modules or segments one at a time while monitoring the bus to find the point where communication returns.
  10. Repair any damaged wiring, replace faulty connectors or modules, and replace/fit proper termination resistors as required.
  11. Reprogram or update module software/firmware if a known update addresses communication issues, then clear codes and retest.
  12. After repair, perform full system scan and a functional test of affected systems to confirm restoration of communication.

Likely causes

  • Open or shorted wiring on Bus D (most common)
  • Failed module transceiver or internal module fault
  • Missing/failed termination resistor(s)
  • Poor ground or power feed to a module on Bus D

Fault status

⚠️ Status
Lost or invalid communication on Vehicle Communication Bus D — one or more modules on this network segment are not responding or data is unavailable.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 to 3.0 hours

Similar codes

U0100 U0073 U0105 U0121 U0140
371

Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U0055

LAND ROVER U — Network/User

Vehicle Communication Bus D

Brand: LAND ROVER
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in Bus D wiring (CAN/lin/other physical layer)
  • Failed node/module (bad transceiver or controller)
  • Poor or corroded ground or power supply to one or more modules on Bus D
  • Blown fuse or defective power supply feeding Bus D modules
  • Incorrect or missing termination resistor(s) on the bus
  • Intermittent connector or pin corrosion at module harnesses

Symptoms

  • Malfunction Indicator Lamp (MIL) or dash warning(s)
  • One or more modules listed as 'not communicating' or missing in a scan tool
  • Loss of specific functions controlled by modules on Bus D (e.g., telematics, body control, infotainment depending on vehicle)
  • Intermittent operation of affected systems
  • Possible no-crank/no-start or limp-home conditions if critical modules are on Bus D

What to check

  • Use OEM scan tool to read all U-codes and identify which modules on Bus D are not responding
  • Visually inspect wiring, connectors, and harnesses for damage/corrosion around modules and along the bus route
  • Check fuses and power/ground at each module on Bus D
  • Measure CAN/communication line voltages with vehicle key in required position (see signal parameters) using a digital multimeter
  • Check continuity and short-to-ground/short-to-B+ on bus wires with power removed or using a current-limited method
  • Inspect and measure termination resistors across the bus (should be about 60 ohms for CAN with two 120 ohm terminators)

Signal parameters

  • CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
  • Typical CAN termination: two 120 ohm resistors in parallel = ~60 ohms measured end-to-end
  • Common CAN bus speeds: 500 kb/s, 250 kb/s, 125 kb/s (verify vehicle-specific speed)
  • Faulty bus may show stuck-high, stuck-low, excessive noise, or missing dominant/recessive transitions on scope

Diagnostic algorithm

  1. Retrieve all stored and pending DTCs from all modules and note freeze-frame data and which modules are non-communicating.
  2. Clear codes, then attempt to re-run network scan to see which DTCs return and whether the fault is current or intermittent.
  3. Identify all modules and wiring that share Bus D from the wiring diagram or vehicle network documentation.
  4. Visually inspect connectors, pins and harnesses at each module and along the bus path for damage, corrosion, or loose pins.
  5. Verify power and ground for each module on Bus D (check fuse(s), battery feed, and module grounds) per manufacturer precautions.
  6. With key in required position, measure idle voltages on the communication lines at a known-good connector. Compare to expected signal parameters.
  7. Measure end-to-end resistance across the bus to verify termination (about 60 ohms for a properly terminated CAN bus).
  8. Use an oscilloscope or CAN analyzer to observe bus traffic and waveform quality; look for missing frames, dominant states held, or noise.
  9. Isolate the fault by disconnecting modules or segments one at a time while monitoring the bus to find the point where communication returns.
  10. Repair any damaged wiring, replace faulty connectors or modules, and replace/fit proper termination resistors as required.
  11. Reprogram or update module software/firmware if a known update addresses communication issues, then clear codes and retest.
  12. After repair, perform full system scan and a functional test of affected systems to confirm restoration of communication.

Likely causes

  • Open or shorted wiring on Bus D (most common)
  • Failed module transceiver or internal module fault
  • Missing/failed termination resistor(s)
  • Poor ground or power feed to a module on Bus D

Fault status

⚠️ Status
Lost or invalid communication on Vehicle Communication Bus D — one or more modules on this network segment are not responding or data is unavailable.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 to 3.0 hours

Similar codes

U0100 U0073 U0105 U0121 U0140
294

Browse 294 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U0055

MERCEDES-BENZ U — Network/User

Vehicle Communication Bus D

Brand: MERCEDES-BENZ
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in Bus D wiring (CAN/lin/other physical layer)
  • Failed node/module (bad transceiver or controller)
  • Poor or corroded ground or power supply to one or more modules on Bus D
  • Blown fuse or defective power supply feeding Bus D modules
  • Incorrect or missing termination resistor(s) on the bus
  • Intermittent connector or pin corrosion at module harnesses

Symptoms

  • Malfunction Indicator Lamp (MIL) or dash warning(s)
  • One or more modules listed as 'not communicating' or missing in a scan tool
  • Loss of specific functions controlled by modules on Bus D (e.g., telematics, body control, infotainment depending on vehicle)
  • Intermittent operation of affected systems
  • Possible no-crank/no-start or limp-home conditions if critical modules are on Bus D

What to check

  • Use OEM scan tool to read all U-codes and identify which modules on Bus D are not responding
  • Visually inspect wiring, connectors, and harnesses for damage/corrosion around modules and along the bus route
  • Check fuses and power/ground at each module on Bus D
  • Measure CAN/communication line voltages with vehicle key in required position (see signal parameters) using a digital multimeter
  • Check continuity and short-to-ground/short-to-B+ on bus wires with power removed or using a current-limited method
  • Inspect and measure termination resistors across the bus (should be about 60 ohms for CAN with two 120 ohm terminators)

Signal parameters

  • CAN bus idle (recessive): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (differential ≈ 0 V)
  • CAN bus dominant state: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
  • Typical CAN termination: two 120 ohm resistors in parallel = ~60 ohms measured end-to-end
  • Common CAN bus speeds: 500 kb/s, 250 kb/s, 125 kb/s (verify vehicle-specific speed)
  • Faulty bus may show stuck-high, stuck-low, excessive noise, or missing dominant/recessive transitions on scope

Diagnostic algorithm

  1. Retrieve all stored and pending DTCs from all modules and note freeze-frame data and which modules are non-communicating.
  2. Clear codes, then attempt to re-run network scan to see which DTCs return and whether the fault is current or intermittent.
  3. Identify all modules and wiring that share Bus D from the wiring diagram or vehicle network documentation.
  4. Visually inspect connectors, pins and harnesses at each module and along the bus path for damage, corrosion, or loose pins.
  5. Verify power and ground for each module on Bus D (check fuse(s), battery feed, and module grounds) per manufacturer precautions.
  6. With key in required position, measure idle voltages on the communication lines at a known-good connector. Compare to expected signal parameters.
  7. Measure end-to-end resistance across the bus to verify termination (about 60 ohms for a properly terminated CAN bus).
  8. Use an oscilloscope or CAN analyzer to observe bus traffic and waveform quality; look for missing frames, dominant states held, or noise.
  9. Isolate the fault by disconnecting modules or segments one at a time while monitoring the bus to find the point where communication returns.
  10. Repair any damaged wiring, replace faulty connectors or modules, and replace/fit proper termination resistors as required.
  11. Reprogram or update module software/firmware if a known update addresses communication issues, then clear codes and retest.
  12. After repair, perform full system scan and a functional test of affected systems to confirm restoration of communication.

Likely causes

  • Open or shorted wiring on Bus D (most common)
  • Failed module transceiver or internal module fault
  • Missing/failed termination resistor(s)
  • Poor ground or power feed to a module on Bus D

Fault status

⚠️ Status
Lost or invalid communication on Vehicle Communication Bus D — one or more modules on this network segment are not responding or data is unavailable.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 to 3.0 hours

Similar codes

U0100 U0073 U0105 U0121 U0140
856

Browse 856 MERCEDES-BENZ manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MERCEDES-BENZ

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .